kernel/bpf/syscall.c | 29 +++++++++++++------ .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++-- 2 files changed, 23 insertions(+), 12 deletions(-)
Previously when retrieving `bpf_link_info.perf_event` for
kprobe/uprobe/tracepoint, the `name_len` field was not populated by the
kernel, leaving it to reflect the value initially set by the user. This
behavior was inconsistent with how other input/output string buffer
fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name. The
relevant selftests have also been updated to assert that `name_len`
contains the correct size rather than 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event")
Signed-off-by: tyrone-wu <wudevelops@gmail.com>
---
V1 -> V2:
Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
- Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 29 +++++++++++++------
.../selftests/bpf/prog_tests/fill_link_info.c | 6 ++--
2 files changed, 23 insertions(+), 12 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a8f1808a1ca5..26cc18693924 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
}
static int bpf_perf_link_fill_common(const struct perf_event *event,
- char __user *uname, u32 ulen,
+ char __user *uname, u32 *ulen,
u64 *probe_offset, u64 *probe_addr,
u32 *fd_type, unsigned long *missed)
{
const char *buf;
u32 prog_id;
- size_t len;
+ size_t len, name_len;
int err;
- if (!ulen ^ !uname)
+ if (!(*ulen) ^ !uname)
return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
probe_offset, probe_addr, missed);
if (err)
return err;
+
+ name_len = *ulen;
+ len = strlen(buf);
+ *ulen = len + 1;
if (!uname)
return 0;
+
if (buf) {
- len = strlen(buf);
- err = bpf_copy_to_user(uname, buf, ulen, len);
+ err = bpf_copy_to_user(uname, buf, name_len, len);
if (err)
return err;
} else {
@@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name);
ulen = info->perf_event.kprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
+ err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
&type, &missed);
if (err)
return err;
@@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
info->perf_event.type = BPF_PERF_EVENT_KRETPROBE;
else
info->perf_event.type = BPF_PERF_EVENT_KPROBE;
-
+ info->perf_event.kprobe.name_len = ulen;
info->perf_event.kprobe.offset = offset;
info->perf_event.kprobe.missed = missed;
if (!kallsyms_show_value(current_cred()))
@@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name);
ulen = info->perf_event.uprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
+ err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
&type, NULL);
if (err)
return err;
@@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
info->perf_event.type = BPF_PERF_EVENT_URETPROBE;
else
info->perf_event.type = BPF_PERF_EVENT_UPROBE;
+ info->perf_event.uprobe.name_len = ulen;
info->perf_event.uprobe.offset = offset;
info->perf_event.uprobe.cookie = event->bpf_cookie;
return 0;
@@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event,
{
char __user *uname;
u32 ulen;
+ int err;
uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name);
ulen = info->perf_event.tracepoint.name_len;
+ err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL);
+ if (err)
+ return err;
+
info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT;
+ info->perf_event.tracepoint.name_len = ulen;
info->perf_event.tracepoint.cookie = event->bpf_cookie;
- return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL);
+ return 0;
}
static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
index f3932941bbaa..59077f260404 100644
--- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
+++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
@@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
+ ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len");
if (!info.perf_event.kprobe.func_name) {
- ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len");
info.perf_event.kprobe.func_name = ptr_to_u64(&buf);
info.perf_event.kprobe.name_len = sizeof(buf);
goto again;
@@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(err, 0, "cmp_kprobe_func_name");
break;
case BPF_PERF_EVENT_TRACEPOINT:
+ ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len");
if (!info.perf_event.tracepoint.tp_name) {
- ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len");
info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf);
info.perf_event.tracepoint.name_len = sizeof(buf);
goto again;
@@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
case BPF_PERF_EVENT_URETPROBE:
ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+ ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len");
if (!info.perf_event.uprobe.file_name) {
- ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len");
info.perf_event.uprobe.file_name = ptr_to_u64(&buf);
info.perf_event.uprobe.name_len = sizeof(buf);
goto again;
--
2.43.0On Wed, Oct 02, 2024 at 09:38:39PM +0000, tyrone-wu wrote:
> Previously when retrieving `bpf_link_info.perf_event` for
> kprobe/uprobe/tracepoint, the `name_len` field was not populated by the
> kernel, leaving it to reflect the value initially set by the user. This
> behavior was inconsistent with how other input/output string buffer
> fields function (e.g. `raw_tracepoint.tp_name_len`).
>
> This patch fills `name_len` with the actual size of the string name. The
> relevant selftests have also been updated to assert that `name_len`
> contains the correct size rather than 0.
>
> Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
> Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event")
> Signed-off-by: tyrone-wu <wudevelops@gmail.com>
> ---
> V1 -> V2:
> Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
> - Use user set *ulen in bpf_copy_to_user before overwriting *ulen
>
> kernel/bpf/syscall.c | 29 +++++++++++++------
> .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++--
> 2 files changed, 23 insertions(+), 12 deletions(-)
>
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index a8f1808a1ca5..26cc18693924 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
> }
>
> static int bpf_perf_link_fill_common(const struct perf_event *event,
> - char __user *uname, u32 ulen,
> + char __user *uname, u32 *ulen,
> u64 *probe_offset, u64 *probe_addr,
> u32 *fd_type, unsigned long *missed)
> {
> const char *buf;
> u32 prog_id;
> - size_t len;
> + size_t len, name_len;
> int err;
>
> - if (!ulen ^ !uname)
> + if (!(*ulen) ^ !uname)
> return -EINVAL;
>
> err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
> probe_offset, probe_addr, missed);
> if (err)
> return err;
> +
> + name_len = *ulen;
> + len = strlen(buf);
> + *ulen = len + 1;
> if (!uname)
> return 0;
> +
> if (buf) {
> - len = strlen(buf);
> - err = bpf_copy_to_user(uname, buf, ulen, len);
> + err = bpf_copy_to_user(uname, buf, name_len, len);
> if (err)
> return err;
> } else {
small nit.. up to you but I'd suggest bit different naming like below,
otherwise looks good
Acked-by: Jiri Olsa <jolsa@kernel.org>
thanks,
jirka
---
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a8f1808a1ca5..b637e9dced5a 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3565,26 +3565,28 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
}
static int bpf_perf_link_fill_common(const struct perf_event *event,
- char __user *uname, u32 ulen,
+ char __user *uname, u32 *ulenp,
u64 *probe_offset, u64 *probe_addr,
u32 *fd_type, unsigned long *missed)
{
const char *buf;
- u32 prog_id;
+ u32 prog_id, ulen;
size_t len;
int err;
- if (!ulen ^ !uname)
+ if (!(*ulenp) ^ !uname)
return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
probe_offset, probe_addr, missed);
if (err)
return err;
+ ulen = *ulenp;
+ len = strlen(buf);
+ *ulenp = len + 1;
if (!uname)
return 0;
if (buf) {
- len = strlen(buf);
err = bpf_copy_to_user(uname, buf, ulen, len);
if (err)
return err;
Previously when retrieving `bpf_link_info.perf_event` for
kprobe/uprobe/tracepoint, the `name_len` field was not populated by the
kernel, leaving it to reflect the value initially set by the user. This
behavior was inconsistent with how other input/output string buffer
fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name. The
relevant selftests have also been updated to assert that `name_len`
contains the correct size rather than 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event")
Signed-off-by: tyrone-wu <wudevelops@gmail.com>
---
V2 -> V3:
Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/
- Use clearer variable name for user set/inputted name len (name_len -> input_len)
- Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
V1 -> V2:
Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
- Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 29 +++++++++++++------
.../selftests/bpf/prog_tests/fill_link_info.c | 6 ++--
2 files changed, 23 insertions(+), 12 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a8f1808a1ca5..56c556fcf325 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
}
static int bpf_perf_link_fill_common(const struct perf_event *event,
- char __user *uname, u32 ulen,
+ char __user *uname, u32 *ulen,
u64 *probe_offset, u64 *probe_addr,
u32 *fd_type, unsigned long *missed)
{
const char *buf;
- u32 prog_id;
+ u32 prog_id, input_len;
size_t len;
int err;
- if (!ulen ^ !uname)
+ if (!(*ulen) ^ !uname)
return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
probe_offset, probe_addr, missed);
if (err)
return err;
+
+ input_len = *ulen;
+ len = strlen(buf);
+ *ulen = len + 1;
if (!uname)
return 0;
+
if (buf) {
- len = strlen(buf);
- err = bpf_copy_to_user(uname, buf, ulen, len);
+ err = bpf_copy_to_user(uname, buf, input_len, len);
if (err)
return err;
} else {
@@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name);
ulen = info->perf_event.kprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
+ err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
&type, &missed);
if (err)
return err;
@@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
info->perf_event.type = BPF_PERF_EVENT_KRETPROBE;
else
info->perf_event.type = BPF_PERF_EVENT_KPROBE;
-
+ info->perf_event.kprobe.name_len = ulen;
info->perf_event.kprobe.offset = offset;
info->perf_event.kprobe.missed = missed;
if (!kallsyms_show_value(current_cred()))
@@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name);
ulen = info->perf_event.uprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
+ err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
&type, NULL);
if (err)
return err;
@@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
info->perf_event.type = BPF_PERF_EVENT_URETPROBE;
else
info->perf_event.type = BPF_PERF_EVENT_UPROBE;
+ info->perf_event.uprobe.name_len = ulen;
info->perf_event.uprobe.offset = offset;
info->perf_event.uprobe.cookie = event->bpf_cookie;
return 0;
@@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event,
{
char __user *uname;
u32 ulen;
+ int err;
uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name);
ulen = info->perf_event.tracepoint.name_len;
+ err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL);
+ if (err)
+ return err;
+
info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT;
+ info->perf_event.tracepoint.name_len = ulen;
info->perf_event.tracepoint.cookie = event->bpf_cookie;
- return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL);
+ return 0;
}
static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
index f3932941bbaa..59077f260404 100644
--- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
+++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
@@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
+ ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len");
if (!info.perf_event.kprobe.func_name) {
- ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len");
info.perf_event.kprobe.func_name = ptr_to_u64(&buf);
info.perf_event.kprobe.name_len = sizeof(buf);
goto again;
@@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(err, 0, "cmp_kprobe_func_name");
break;
case BPF_PERF_EVENT_TRACEPOINT:
+ ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len");
if (!info.perf_event.tracepoint.tp_name) {
- ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len");
info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf);
info.perf_event.tracepoint.name_len = sizeof(buf);
goto again;
@@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
case BPF_PERF_EVENT_URETPROBE:
ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+ ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len");
if (!info.perf_event.uprobe.file_name) {
- ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len");
info.perf_event.uprobe.file_name = ptr_to_u64(&buf);
info.perf_event.uprobe.name_len = sizeof(buf);
goto again;
--
2.43.0On Thu, Oct 03, 2024 at 08:23:00PM +0000, tyrone-wu wrote:
> Previously when retrieving `bpf_link_info.perf_event` for
> kprobe/uprobe/tracepoint, the `name_len` field was not populated by the
> kernel, leaving it to reflect the value initially set by the user. This
> behavior was inconsistent with how other input/output string buffer
> fields function (e.g. `raw_tracepoint.tp_name_len`).
>
> This patch fills `name_len` with the actual size of the string name. The
> relevant selftests have also been updated to assert that `name_len`
> contains the correct size rather than 0.
>
> Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
> Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event")
> Signed-off-by: tyrone-wu <wudevelops@gmail.com>
> ---
> V2 -> V3:
> Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/
> - Use clearer variable name for user set/inputted name len (name_len -> input_len)
> - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
looks good, I checked with Daniel and it's better to separate
kernel and selftest changes, so it's easier to get this applied
in stable branches
could you split the change in 2 changes and repost? please keep my ack
thanks,
jirka
>
> V1 -> V2:
> Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
> - Use user set *ulen in bpf_copy_to_user before overwriting *ulen
>
> kernel/bpf/syscall.c | 29 +++++++++++++------
> .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++--
> 2 files changed, 23 insertions(+), 12 deletions(-)
>
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index a8f1808a1ca5..56c556fcf325 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
> }
>
> static int bpf_perf_link_fill_common(const struct perf_event *event,
> - char __user *uname, u32 ulen,
> + char __user *uname, u32 *ulen,
> u64 *probe_offset, u64 *probe_addr,
> u32 *fd_type, unsigned long *missed)
> {
> const char *buf;
> - u32 prog_id;
> + u32 prog_id, input_len;
> size_t len;
> int err;
>
> - if (!ulen ^ !uname)
> + if (!(*ulen) ^ !uname)
> return -EINVAL;
>
> err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
> probe_offset, probe_addr, missed);
> if (err)
> return err;
> +
> + input_len = *ulen;
> + len = strlen(buf);
> + *ulen = len + 1;
> if (!uname)
> return 0;
> +
> if (buf) {
> - len = strlen(buf);
> - err = bpf_copy_to_user(uname, buf, ulen, len);
> + err = bpf_copy_to_user(uname, buf, input_len, len);
> if (err)
> return err;
> } else {
> @@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
>
> uname = u64_to_user_ptr(info->perf_event.kprobe.func_name);
> ulen = info->perf_event.kprobe.name_len;
> - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
> + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
> &type, &missed);
> if (err)
> return err;
> @@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
> info->perf_event.type = BPF_PERF_EVENT_KRETPROBE;
> else
> info->perf_event.type = BPF_PERF_EVENT_KPROBE;
> -
> + info->perf_event.kprobe.name_len = ulen;
> info->perf_event.kprobe.offset = offset;
> info->perf_event.kprobe.missed = missed;
> if (!kallsyms_show_value(current_cred()))
> @@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
>
> uname = u64_to_user_ptr(info->perf_event.uprobe.file_name);
> ulen = info->perf_event.uprobe.name_len;
> - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
> + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
> &type, NULL);
> if (err)
> return err;
> @@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
> info->perf_event.type = BPF_PERF_EVENT_URETPROBE;
> else
> info->perf_event.type = BPF_PERF_EVENT_UPROBE;
> + info->perf_event.uprobe.name_len = ulen;
> info->perf_event.uprobe.offset = offset;
> info->perf_event.uprobe.cookie = event->bpf_cookie;
> return 0;
> @@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event,
> {
> char __user *uname;
> u32 ulen;
> + int err;
>
> uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name);
> ulen = info->perf_event.tracepoint.name_len;
> + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL);
> + if (err)
> + return err;
> +
> info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT;
> + info->perf_event.tracepoint.name_len = ulen;
> info->perf_event.tracepoint.cookie = event->bpf_cookie;
> - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL);
> + return 0;
> }
>
> static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
> diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
> index f3932941bbaa..59077f260404 100644
> --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
> +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
> @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
>
> ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
>
> + ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len");
> if (!info.perf_event.kprobe.func_name) {
> - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len");
> info.perf_event.kprobe.func_name = ptr_to_u64(&buf);
> info.perf_event.kprobe.name_len = sizeof(buf);
> goto again;
> @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
> ASSERT_EQ(err, 0, "cmp_kprobe_func_name");
> break;
> case BPF_PERF_EVENT_TRACEPOINT:
> + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len");
> if (!info.perf_event.tracepoint.tp_name) {
> - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len");
> info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf);
> info.perf_event.tracepoint.name_len = sizeof(buf);
> goto again;
> @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
> case BPF_PERF_EVENT_URETPROBE:
> ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
>
> + ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len");
> if (!info.perf_event.uprobe.file_name) {
> - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len");
> info.perf_event.uprobe.file_name = ptr_to_u64(&buf);
> info.perf_event.uprobe.name_len = sizeof(buf);
> goto again;
> --
> 2.43.0
>
Previously when retrieving `bpf_link_info.perf_event` for
kprobe/uprobe/tracepoint, the `name_len` field was not populated by the
kernel, leaving it to reflect the value initially set by the user. This
behavior was inconsistent with how other input/output string buffer
fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event")
Signed-off-by: tyrone-wu <wudevelops@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
---
V3 -> V4:
Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
- Split patch into separate kernel and selftest change
V2 -> V3:
Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/
- Use clearer variable name for user set/inputted name len (name_len -> input_len)
- Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
V1 -> V2:
Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
- Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 29 ++++++++++++++++++++---------
1 file changed, 20 insertions(+), 9 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a8f1808a1ca5..56c556fcf325 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
}
static int bpf_perf_link_fill_common(const struct perf_event *event,
- char __user *uname, u32 ulen,
+ char __user *uname, u32 *ulen,
u64 *probe_offset, u64 *probe_addr,
u32 *fd_type, unsigned long *missed)
{
const char *buf;
- u32 prog_id;
+ u32 prog_id, input_len;
size_t len;
int err;
- if (!ulen ^ !uname)
+ if (!(*ulen) ^ !uname)
return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
probe_offset, probe_addr, missed);
if (err)
return err;
+
+ input_len = *ulen;
+ len = strlen(buf);
+ *ulen = len + 1;
if (!uname)
return 0;
+
if (buf) {
- len = strlen(buf);
- err = bpf_copy_to_user(uname, buf, ulen, len);
+ err = bpf_copy_to_user(uname, buf, input_len, len);
if (err)
return err;
} else {
@@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name);
ulen = info->perf_event.kprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
+ err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
&type, &missed);
if (err)
return err;
@@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
info->perf_event.type = BPF_PERF_EVENT_KRETPROBE;
else
info->perf_event.type = BPF_PERF_EVENT_KPROBE;
-
+ info->perf_event.kprobe.name_len = ulen;
info->perf_event.kprobe.offset = offset;
info->perf_event.kprobe.missed = missed;
if (!kallsyms_show_value(current_cred()))
@@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name);
ulen = info->perf_event.uprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
+ err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
&type, NULL);
if (err)
return err;
@@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
info->perf_event.type = BPF_PERF_EVENT_URETPROBE;
else
info->perf_event.type = BPF_PERF_EVENT_UPROBE;
+ info->perf_event.uprobe.name_len = ulen;
info->perf_event.uprobe.offset = offset;
info->perf_event.uprobe.cookie = event->bpf_cookie;
return 0;
@@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event,
{
char __user *uname;
u32 ulen;
+ int err;
uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name);
ulen = info->perf_event.tracepoint.name_len;
+ err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL);
+ if (err)
+ return err;
+
info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT;
+ info->perf_event.tracepoint.name_len = ulen;
info->perf_event.tracepoint.cookie = event->bpf_cookie;
- return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL);
+ return 0;
}
static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
--
2.43.0On Fri, Oct 4, 2024 at 11:40 PM tyrone-wu <wudevelops@gmail.com> wrote:
>
> Previously when retrieving `bpf_link_info.perf_event` for
> kprobe/uprobe/tracepoint, the `name_len` field was not populated by the
> kernel, leaving it to reflect the value initially set by the user. This
> behavior was inconsistent with how other input/output string buffer
> fields function (e.g. `raw_tracepoint.tp_name_len`).
>
> This patch fills `name_len` with the actual size of the string name.
>
> Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
> Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event")
> Signed-off-by: tyrone-wu <wudevelops@gmail.com>
> Acked-by: Jiri Olsa <jolsa@kernel.org>
> ---
> V3 -> V4:
> Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
> - Split patch into separate kernel and selftest change
>
> V2 -> V3:
> Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/
> - Use clearer variable name for user set/inputted name len (name_len -> input_len)
> - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
>
> V1 -> V2:
> Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
> - Use user set *ulen in bpf_copy_to_user before overwriting *ulen
>
> kernel/bpf/syscall.c | 29 ++++++++++++++++++++---------
> 1 file changed, 20 insertions(+), 9 deletions(-)
>
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index a8f1808a1ca5..56c556fcf325 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
> }
>
> static int bpf_perf_link_fill_common(const struct perf_event *event,
> - char __user *uname, u32 ulen,
> + char __user *uname, u32 *ulen,
> u64 *probe_offset, u64 *probe_addr,
> u32 *fd_type, unsigned long *missed)
> {
> const char *buf;
> - u32 prog_id;
> + u32 prog_id, input_len;
> size_t len;
> int err;
>
> - if (!ulen ^ !uname)
> + if (!(*ulen) ^ !uname)
> return -EINVAL;
>
> err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
> probe_offset, probe_addr, missed);
> if (err)
> return err;
> +
> + input_len = *ulen;
> + len = strlen(buf);
The buf might be NULL, so we should check it.
> + *ulen = len + 1;
> if (!uname)
> return 0;
> +
> if (buf) {
> - len = strlen(buf);
> - err = bpf_copy_to_user(uname, buf, ulen, len);
> + err = bpf_copy_to_user(uname, buf, input_len, len);
> if (err)
> return err;
> } else {
> @@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
>
> uname = u64_to_user_ptr(info->perf_event.kprobe.func_name);
> ulen = info->perf_event.kprobe.name_len;
> - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
> + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
> &type, &missed);
> if (err)
> return err;
> @@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
> info->perf_event.type = BPF_PERF_EVENT_KRETPROBE;
> else
> info->perf_event.type = BPF_PERF_EVENT_KPROBE;
> -
> + info->perf_event.kprobe.name_len = ulen;
> info->perf_event.kprobe.offset = offset;
> info->perf_event.kprobe.missed = missed;
> if (!kallsyms_show_value(current_cred()))
> @@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
>
> uname = u64_to_user_ptr(info->perf_event.uprobe.file_name);
> ulen = info->perf_event.uprobe.name_len;
> - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
> + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
> &type, NULL);
> if (err)
> return err;
> @@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
> info->perf_event.type = BPF_PERF_EVENT_URETPROBE;
> else
> info->perf_event.type = BPF_PERF_EVENT_UPROBE;
> + info->perf_event.uprobe.name_len = ulen;
> info->perf_event.uprobe.offset = offset;
> info->perf_event.uprobe.cookie = event->bpf_cookie;
> return 0;
> @@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event,
> {
> char __user *uname;
> u32 ulen;
> + int err;
>
> uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name);
> ulen = info->perf_event.tracepoint.name_len;
> + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL);
> + if (err)
> + return err;
> +
> info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT;
> + info->perf_event.tracepoint.name_len = ulen;
> info->perf_event.tracepoint.cookie = event->bpf_cookie;
> - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL);
> + return 0;
> }
>
> static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
> --
> 2.43.0
>
--
Regards
Yafang
Previously when retrieving `bpf_link_info.perf_event` for
kprobe/uprobe/tracepoint, the `name_len` field was not populated by the
kernel, leaving it to reflect the value initially set by the user. This
behavior was inconsistent with how other input/output string buffer
fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event")
Signed-off-by: tyrone-wu <wudevelops@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
---
V4 -> V5:
Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZp-Q@mail.gmail.com/
- Check that buf is not NULL before retrieving/using its length
V3 -> V4:
Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
- Split patch into separate kernel and selftest change
V2 -> V3:
Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/
- Use clearer variable name for user set/inputted name len (name_len -> input_len)
- Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
V1 -> V2:
Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
- Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 38 ++++++++++++++++++++++++--------------
1 file changed, 24 insertions(+), 14 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a8f1808a1ca5..3df192a6bdcc 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3565,32 +3565,35 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
}
static int bpf_perf_link_fill_common(const struct perf_event *event,
- char __user *uname, u32 ulen,
+ char __user *uname, u32 *ulen,
u64 *probe_offset, u64 *probe_addr,
u32 *fd_type, unsigned long *missed)
{
const char *buf;
- u32 prog_id;
+ u32 prog_id, input_len;
size_t len;
int err;
- if (!ulen ^ !uname)
+ if (!(*ulen) ^ !uname)
return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
probe_offset, probe_addr, missed);
if (err)
return err;
- if (!uname)
- return 0;
+
if (buf) {
+ input_len = *ulen;
len = strlen(buf);
- err = bpf_copy_to_user(uname, buf, ulen, len);
- if (err)
- return err;
- } else {
- char zero = '\0';
+ *ulen = len + 1;
+ if (uname) {
+ err = bpf_copy_to_user(uname, buf, input_len, len);
+ if (err)
+ return err;
+ }
+ } else if (uname) {
+ char zero = '\0';
if (put_user(zero, uname))
return -EFAULT;
}
@@ -3609,7 +3612,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name);
ulen = info->perf_event.kprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
+ err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
&type, &missed);
if (err)
return err;
@@ -3617,7 +3620,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
info->perf_event.type = BPF_PERF_EVENT_KRETPROBE;
else
info->perf_event.type = BPF_PERF_EVENT_KPROBE;
-
+ info->perf_event.kprobe.name_len = ulen;
info->perf_event.kprobe.offset = offset;
info->perf_event.kprobe.missed = missed;
if (!kallsyms_show_value(current_cred()))
@@ -3639,7 +3642,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name);
ulen = info->perf_event.uprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
+ err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
&type, NULL);
if (err)
return err;
@@ -3648,6 +3651,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
info->perf_event.type = BPF_PERF_EVENT_URETPROBE;
else
info->perf_event.type = BPF_PERF_EVENT_UPROBE;
+ info->perf_event.uprobe.name_len = ulen;
info->perf_event.uprobe.offset = offset;
info->perf_event.uprobe.cookie = event->bpf_cookie;
return 0;
@@ -3673,12 +3677,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event,
{
char __user *uname;
u32 ulen;
+ int err;
uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name);
ulen = info->perf_event.tracepoint.name_len;
+ err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL);
+ if (err)
+ return err;
+
info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT;
+ info->perf_event.tracepoint.name_len = ulen;
info->perf_event.tracepoint.cookie = event->bpf_cookie;
- return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL);
+ return 0;
}
static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
--
2.43.0On Sun, Oct 06, 2024 at 07:51:30PM +0000, tyrone-wu wrote:
> Previously when retrieving `bpf_link_info.perf_event` for
> kprobe/uprobe/tracepoint, the `name_len` field was not populated by the
> kernel, leaving it to reflect the value initially set by the user. This
> behavior was inconsistent with how other input/output string buffer
> fields function (e.g. `raw_tracepoint.tp_name_len`).
>
> This patch fills `name_len` with the actual size of the string name.
>
> Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
> Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event")
> Signed-off-by: tyrone-wu <wudevelops@gmail.com>
> Acked-by: Jiri Olsa <jolsa@kernel.org>
> ---
> V4 -> V5:
> Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZp-Q@mail.gmail.com/
> - Check that buf is not NULL before retrieving/using its length
>
> V3 -> V4:
> Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
> - Split patch into separate kernel and selftest change
>
> V2 -> V3:
> Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/
> - Use clearer variable name for user set/inputted name len (name_len -> input_len)
> - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
>
> V1 -> V2:
> Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
> - Use user set *ulen in bpf_copy_to_user before overwriting *ulen
>
> kernel/bpf/syscall.c | 38 ++++++++++++++++++++++++--------------
> 1 file changed, 24 insertions(+), 14 deletions(-)
>
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index a8f1808a1ca5..3df192a6bdcc 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -3565,32 +3565,35 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
> }
>
> static int bpf_perf_link_fill_common(const struct perf_event *event,
> - char __user *uname, u32 ulen,
> + char __user *uname, u32 *ulen,
> u64 *probe_offset, u64 *probe_addr,
> u32 *fd_type, unsigned long *missed)
> {
> const char *buf;
> - u32 prog_id;
> + u32 prog_id, input_len;
> size_t len;
> int err;
>
> - if (!ulen ^ !uname)
> + if (!(*ulen) ^ !uname)
> return -EINVAL;
>
> err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
> probe_offset, probe_addr, missed);
> if (err)
> return err;
> - if (!uname)
> - return 0;
> +
> if (buf) {
> + input_len = *ulen;
> len = strlen(buf);
> - err = bpf_copy_to_user(uname, buf, ulen, len);
> - if (err)
> - return err;
> - } else {
> - char zero = '\0';
> + *ulen = len + 1;
>
> + if (uname) {
> + err = bpf_copy_to_user(uname, buf, input_len, len);
> + if (err)
> + return err;
> + }
> + } else if (uname) {
> + char zero = '\0';
> if (put_user(zero, uname))
> return -EFAULT;
> }
hm, why not just simple check buf for and keep the rest? seems less complicated..
jirka
---
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a8f1808a1ca5..e393b94b90ec 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
}
static int bpf_perf_link_fill_common(const struct perf_event *event,
- char __user *uname, u32 ulen,
+ char __user *uname, u32 *ulen,
u64 *probe_offset, u64 *probe_addr,
u32 *fd_type, unsigned long *missed)
{
const char *buf;
- u32 prog_id;
+ u32 prog_id, input_len;
size_t len;
int err;
- if (!ulen ^ !uname)
+ if (!(*ulen) ^ !uname)
return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
probe_offset, probe_addr, missed);
if (err)
return err;
+ if (buf) {
+ input_len = *ulen;
+ len = strlen(buf);
+ *ulen = len + 1;
+ }
if (!uname)
return 0;
if (buf) {
- len = strlen(buf);
- err = bpf_copy_to_user(uname, buf, ulen, len);
+ err = bpf_copy_to_user(uname, buf, input_len, len);
if (err)
return err;
} else {
From: tyrone-wu <wudevelops@gmail.com>
Previously when retrieving `bpf_link_info.perf_event` for
kprobe/uprobe/tracepoint, the `name_len` field was not populated by the
kernel, leaving it to reflect the value initially set by the user. This
behavior was inconsistent with how other input/output string buffer
fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event")
Signed-off-by: Tyrone Wu <wudevelops@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
---
V5 -> V6:
Link: https://lore.kernel.org/bpf/ZwOWs_XrBtlTGE24@krava/
- Use simpler buf check while keeping V4
- Fix netdev/checkpatch warning for 80 cols exceeded
- Fix Signed-off-by to use real name instead of git username
V4 -> V5:
Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZp-Q@mail.gmail.com/
- Check that buf is not NULL before retrieving/using its length
V3 -> V4:
Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
- Split patch into separate kernel and selftest change
V2 -> V3:
Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/
- Use clearer variable name for user set/inputted name len (name_len -> input_len)
- Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
V1 -> V2:
Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
- Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 32 +++++++++++++++++++++++---------
1 file changed, 23 insertions(+), 9 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a8f1808a1ca5..b5a7e428ac16 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3565,27 +3565,33 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
}
static int bpf_perf_link_fill_common(const struct perf_event *event,
- char __user *uname, u32 ulen,
+ char __user *uname, u32 *ulen,
u64 *probe_offset, u64 *probe_addr,
u32 *fd_type, unsigned long *missed)
{
const char *buf;
- u32 prog_id;
+ u32 prog_id, input_len;
size_t len;
int err;
- if (!ulen ^ !uname)
+ if (!(*ulen) ^ !uname)
return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
probe_offset, probe_addr, missed);
if (err)
return err;
+
+ if (buf) {
+ input_len = *ulen;
+ len = strlen(buf);
+ *ulen = len + 1;
+ }
if (!uname)
return 0;
+
if (buf) {
- len = strlen(buf);
- err = bpf_copy_to_user(uname, buf, ulen, len);
+ err = bpf_copy_to_user(uname, buf, input_len, len);
if (err)
return err;
} else {
@@ -3609,7 +3615,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name);
ulen = info->perf_event.kprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
+ err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
&type, &missed);
if (err)
return err;
@@ -3617,7 +3623,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
info->perf_event.type = BPF_PERF_EVENT_KRETPROBE;
else
info->perf_event.type = BPF_PERF_EVENT_KPROBE;
-
+ info->perf_event.kprobe.name_len = ulen;
info->perf_event.kprobe.offset = offset;
info->perf_event.kprobe.missed = missed;
if (!kallsyms_show_value(current_cred()))
@@ -3639,7 +3645,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name);
ulen = info->perf_event.uprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
+ err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
&type, NULL);
if (err)
return err;
@@ -3648,6 +3654,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
info->perf_event.type = BPF_PERF_EVENT_URETPROBE;
else
info->perf_event.type = BPF_PERF_EVENT_UPROBE;
+ info->perf_event.uprobe.name_len = ulen;
info->perf_event.uprobe.offset = offset;
info->perf_event.uprobe.cookie = event->bpf_cookie;
return 0;
@@ -3673,12 +3680,19 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event,
{
char __user *uname;
u32 ulen;
+ int err;
uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name);
ulen = info->perf_event.tracepoint.name_len;
+ err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL,
+ NULL);
+ if (err)
+ return err;
+
info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT;
+ info->perf_event.tracepoint.name_len = ulen;
info->perf_event.tracepoint.cookie = event->bpf_cookie;
- return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL);
+ return 0;
}
static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
--
2.43.0On Mon, Oct 7, 2024 at 11:29 AM Tyrone Wu <wudevelops@gmail.com> wrote:
>
> From: tyrone-wu <wudevelops@gmail.com>
>
> Previously when retrieving `bpf_link_info.perf_event` for
> kprobe/uprobe/tracepoint, the `name_len` field was not populated by the
> kernel, leaving it to reflect the value initially set by the user. This
> behavior was inconsistent with how other input/output string buffer
> fields function (e.g. `raw_tracepoint.tp_name_len`).
>
> This patch fills `name_len` with the actual size of the string name.
>
> Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
> Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event")
> Signed-off-by: Tyrone Wu <wudevelops@gmail.com>
> Acked-by: Jiri Olsa <jolsa@kernel.org>
> Acked-by: Yafang Shao <laoar.shao@gmail.com>
> ---
> V5 -> V6:
> Link: https://lore.kernel.org/bpf/ZwOWs_XrBtlTGE24@krava/
> - Use simpler buf check while keeping V4
> - Fix netdev/checkpatch warning for 80 cols exceeded
> - Fix Signed-off-by to use real name instead of git username
>
> V4 -> V5:
> Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZp-Q@mail.gmail.com/
> - Check that buf is not NULL before retrieving/using its length
>
> V3 -> V4:
> Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
> - Split patch into separate kernel and selftest change
>
> V2 -> V3:
> Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/
> - Use clearer variable name for user set/inputted name len (name_len -> input_len)
> - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
>
> V1 -> V2:
> Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
Please drop all the Link: tags, our scripts will accumulate all of
them in the final commit and it becomes very confusing. Our script
will add the final Link: for your latest applied version anyways.
Also, git still shows:
Author: tyrone-wu <wudevelops@gmail.com>
So please try to fix that.
But generally, looks good and I almost applied, but see one small
issue below, which I think needs fixing.
pw-bot: cr
> - Use user set *ulen in bpf_copy_to_user before overwriting *ulen
>
> kernel/bpf/syscall.c | 32 +++++++++++++++++++++++---------
> 1 file changed, 23 insertions(+), 9 deletions(-)
>
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index a8f1808a1ca5..b5a7e428ac16 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -3565,27 +3565,33 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
> }
>
> static int bpf_perf_link_fill_common(const struct perf_event *event,
> - char __user *uname, u32 ulen,
> + char __user *uname, u32 *ulen,
nit: I'd do what Jiri suggested, use `u32 *ulenp` here
> u64 *probe_offset, u64 *probe_addr,
> u32 *fd_type, unsigned long *missed)
> {
> const char *buf;
> - u32 prog_id;
> + u32 prog_id, input_len;
and then just `u32 ulen;` here.
> size_t len;
> int err;
>
start with just
ulen = *ulenp;
> - if (!ulen ^ !uname)
> + if (!(*ulen) ^ !uname)
and remove all the `*ulen` uses except the final assignment
> return -EINVAL;
>
> err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
> probe_offset, probe_addr, missed);
> if (err)
> return err;
> +
> + if (buf) {
> + input_len = *ulen;
> + len = strlen(buf);
> + *ulen = len + 1;
> + }
don't we need
} else {
*ulen = 1;
}
for cases when we don't have buf returned from
bpf_get_perf_event_info()? Though I don't think it can happen
currently, existing code is clearly ready to handle that case, so
let's keep it consistent.
> if (!uname)
> return 0;
> +
> if (buf) {
> - len = strlen(buf);
> - err = bpf_copy_to_user(uname, buf, ulen, len);
> + err = bpf_copy_to_user(uname, buf, input_len, len);
> if (err)
> return err;
> } else {
> @@ -3609,7 +3615,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
>
> uname = u64_to_user_ptr(info->perf_event.kprobe.func_name);
> ulen = info->perf_event.kprobe.name_len;
> - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
> + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
> &type, &missed);
> if (err)
> return err;
> @@ -3617,7 +3623,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
> info->perf_event.type = BPF_PERF_EVENT_KRETPROBE;
> else
> info->perf_event.type = BPF_PERF_EVENT_KPROBE;
> -
> + info->perf_event.kprobe.name_len = ulen;
> info->perf_event.kprobe.offset = offset;
> info->perf_event.kprobe.missed = missed;
> if (!kallsyms_show_value(current_cred()))
> @@ -3639,7 +3645,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
>
> uname = u64_to_user_ptr(info->perf_event.uprobe.file_name);
> ulen = info->perf_event.uprobe.name_len;
> - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
> + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
> &type, NULL);
> if (err)
> return err;
> @@ -3648,6 +3654,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
> info->perf_event.type = BPF_PERF_EVENT_URETPROBE;
> else
> info->perf_event.type = BPF_PERF_EVENT_UPROBE;
> + info->perf_event.uprobe.name_len = ulen;
> info->perf_event.uprobe.offset = offset;
> info->perf_event.uprobe.cookie = event->bpf_cookie;
> return 0;
> @@ -3673,12 +3680,19 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event,
> {
> char __user *uname;
> u32 ulen;
> + int err;
>
> uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name);
> ulen = info->perf_event.tracepoint.name_len;
> + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL,
> + NULL);
nit: keep it on a single line
> + if (err)
> + return err;
> +
> info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT;
> + info->perf_event.tracepoint.name_len = ulen;
> info->perf_event.tracepoint.cookie = event->bpf_cookie;
> - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL);
> + return 0;
> }
>
> static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
> --
> 2.43.0
>
Previously when retrieving `bpf_link_info.perf_event` for
kprobe/uprobe/tracepoint, the `name_len` field was not populated by the
kernel, leaving it to reflect the value initially set by the user. This
behavior was inconsistent with how other input/output string buffer
fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name.
Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event")
Signed-off-by: Tyrone Wu <wudevelops@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
---
V6 -> V7:
- Use *ulenp suggestion from Jiri for user name_len
- Set user name_len to 1 when buf returned from bpf_get_perf_event_info() is NULL
V5 -> V6:
- Use simpler buf check while keeping V4
- Fix netdev/checkpatch warning for 80 cols exceeded
- Fix Signed-off-by to use real name instead of git username
V4 -> V5:
- Check that buf is not NULL before retrieving/using its length
V3 -> V4:
- Split patch into separate kernel and selftest change
V2 -> V3:
- Use clearer variable name for user set/inputted name len (name_len -> input_len)
- Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
V1 -> V2:
- Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 29 ++++++++++++++++++++++-------
1 file changed, 22 insertions(+), 7 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a8f1808a1ca5..8cfa7183d2ef 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3565,15 +3565,16 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
}
static int bpf_perf_link_fill_common(const struct perf_event *event,
- char __user *uname, u32 ulen,
+ char __user *uname, u32 *ulenp,
u64 *probe_offset, u64 *probe_addr,
u32 *fd_type, unsigned long *missed)
{
const char *buf;
- u32 prog_id;
+ u32 prog_id, ulen;
size_t len;
int err;
+ ulen = *ulenp;
if (!ulen ^ !uname)
return -EINVAL;
@@ -3581,10 +3582,17 @@ static int bpf_perf_link_fill_common(const struct perf_event *event,
probe_offset, probe_addr, missed);
if (err)
return err;
+
+ if (buf) {
+ len = strlen(buf);
+ *ulenp = len + 1;
+ } else {
+ *ulenp = 1;
+ }
if (!uname)
return 0;
+
if (buf) {
- len = strlen(buf);
err = bpf_copy_to_user(uname, buf, ulen, len);
if (err)
return err;
@@ -3609,7 +3617,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name);
ulen = info->perf_event.kprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
+ err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
&type, &missed);
if (err)
return err;
@@ -3617,7 +3625,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
info->perf_event.type = BPF_PERF_EVENT_KRETPROBE;
else
info->perf_event.type = BPF_PERF_EVENT_KPROBE;
-
+ info->perf_event.kprobe.name_len = ulen;
info->perf_event.kprobe.offset = offset;
info->perf_event.kprobe.missed = missed;
if (!kallsyms_show_value(current_cred()))
@@ -3639,7 +3647,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name);
ulen = info->perf_event.uprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
+ err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
&type, NULL);
if (err)
return err;
@@ -3648,6 +3656,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
info->perf_event.type = BPF_PERF_EVENT_URETPROBE;
else
info->perf_event.type = BPF_PERF_EVENT_UPROBE;
+ info->perf_event.uprobe.name_len = ulen;
info->perf_event.uprobe.offset = offset;
info->perf_event.uprobe.cookie = event->bpf_cookie;
return 0;
@@ -3673,12 +3682,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event,
{
char __user *uname;
u32 ulen;
+ int err;
uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name);
ulen = info->perf_event.tracepoint.name_len;
+ err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL);
+ if (err)
+ return err;
+
info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT;
+ info->perf_event.tracepoint.name_len = ulen;
info->perf_event.tracepoint.cookie = event->bpf_cookie;
- return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL);
+ return 0;
}
static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
--
2.43.0Fix `name_len` field assertions in `bpf_link_info.perf_event` for
kprobe/uprobe/tracepoint to validate correct name size instead of 0.
Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info")
Signed-off-by: Tyrone Wu <wudevelops@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
---
V6 -> V7: no change
V5 -> V6:
- Fix netdev/checkpatch warning for 80 cols exceeded
- Fix Signed-off-by to use real name instead of git username
V4 -> V5: no change
V3 -> V4:
- Split patch into separate kernel and selftest change
tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
index f3932941bbaa..745c5ada4c4b 100644
--- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
+++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
@@ -67,8 +67,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
+ ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1,
+ "name_len");
if (!info.perf_event.kprobe.func_name) {
- ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len");
info.perf_event.kprobe.func_name = ptr_to_u64(&buf);
info.perf_event.kprobe.name_len = sizeof(buf);
goto again;
@@ -79,8 +80,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(err, 0, "cmp_kprobe_func_name");
break;
case BPF_PERF_EVENT_TRACEPOINT:
+ ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1,
+ "name_len");
if (!info.perf_event.tracepoint.tp_name) {
- ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len");
info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf);
info.perf_event.tracepoint.name_len = sizeof(buf);
goto again;
@@ -96,8 +98,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
case BPF_PERF_EVENT_URETPROBE:
ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+ ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1,
+ "name_len");
if (!info.perf_event.uprobe.file_name) {
- ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len");
info.perf_event.uprobe.file_name = ptr_to_u64(&buf);
info.perf_event.uprobe.name_len = sizeof(buf);
goto again;
--
2.43.0From: tyrone-wu <wudevelops@gmail.com>
Fix `name_len` field assertions in `bpf_link_info.perf_event` for
kprobe/uprobe/tracepoint to validate correct name size instead of 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info")
Signed-off-by: Tyrone Wu <wudevelops@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
---
V5 -> V6:
- Fix netdev/checkpatch warning for 80 cols exceeded
- Fix Signed-off-by to use real name instead of git username
V4 -> V5: no change
V3 -> V4:
Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
- Split patch into separate kernel and selftest change
tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
index f3932941bbaa..745c5ada4c4b 100644
--- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
+++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
@@ -67,8 +67,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
+ ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1,
+ "name_len");
if (!info.perf_event.kprobe.func_name) {
- ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len");
info.perf_event.kprobe.func_name = ptr_to_u64(&buf);
info.perf_event.kprobe.name_len = sizeof(buf);
goto again;
@@ -79,8 +80,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(err, 0, "cmp_kprobe_func_name");
break;
case BPF_PERF_EVENT_TRACEPOINT:
+ ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1,
+ "name_len");
if (!info.perf_event.tracepoint.tp_name) {
- ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len");
info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf);
info.perf_event.tracepoint.name_len = sizeof(buf);
goto again;
@@ -96,8 +98,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
case BPF_PERF_EVENT_URETPROBE:
ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+ ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1,
+ "name_len");
if (!info.perf_event.uprobe.file_name) {
- ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len");
info.perf_event.uprobe.file_name = ptr_to_u64(&buf);
info.perf_event.uprobe.name_len = sizeof(buf);
goto again;
--
2.43.0On Mon, Oct 7, 2024 at 3:51 AM tyrone-wu <wudevelops@gmail.com> wrote:
>
> Previously when retrieving `bpf_link_info.perf_event` for
> kprobe/uprobe/tracepoint, the `name_len` field was not populated by the
> kernel, leaving it to reflect the value initially set by the user. This
> behavior was inconsistent with how other input/output string buffer
> fields function (e.g. `raw_tracepoint.tp_name_len`).
>
> This patch fills `name_len` with the actual size of the string name.
>
> Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
> Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event")
> Signed-off-by: tyrone-wu <wudevelops@gmail.com>
> Acked-by: Jiri Olsa <jolsa@kernel.org>
LGTM
Acked-by: Yafang Shao <laoar.shao@gmail.com>
> ---
> V4 -> V5:
> Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZp-Q@mail.gmail.com/
> - Check that buf is not NULL before retrieving/using its length
>
> V3 -> V4:
> Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
> - Split patch into separate kernel and selftest change
>
> V2 -> V3:
> Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/
> - Use clearer variable name for user set/inputted name len (name_len -> input_len)
> - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
>
> V1 -> V2:
> Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
> - Use user set *ulen in bpf_copy_to_user before overwriting *ulen
>
> kernel/bpf/syscall.c | 38 ++++++++++++++++++++++++--------------
> 1 file changed, 24 insertions(+), 14 deletions(-)
>
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index a8f1808a1ca5..3df192a6bdcc 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -3565,32 +3565,35 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
> }
>
> static int bpf_perf_link_fill_common(const struct perf_event *event,
> - char __user *uname, u32 ulen,
> + char __user *uname, u32 *ulen,
> u64 *probe_offset, u64 *probe_addr,
> u32 *fd_type, unsigned long *missed)
> {
> const char *buf;
> - u32 prog_id;
> + u32 prog_id, input_len;
> size_t len;
> int err;
>
> - if (!ulen ^ !uname)
> + if (!(*ulen) ^ !uname)
> return -EINVAL;
>
> err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
> probe_offset, probe_addr, missed);
> if (err)
> return err;
> - if (!uname)
> - return 0;
> +
> if (buf) {
> + input_len = *ulen;
> len = strlen(buf);
> - err = bpf_copy_to_user(uname, buf, ulen, len);
> - if (err)
> - return err;
> - } else {
> - char zero = '\0';
> + *ulen = len + 1;
>
> + if (uname) {
> + err = bpf_copy_to_user(uname, buf, input_len, len);
> + if (err)
> + return err;
> + }
> + } else if (uname) {
> + char zero = '\0';
> if (put_user(zero, uname))
> return -EFAULT;
> }
> @@ -3609,7 +3612,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
>
> uname = u64_to_user_ptr(info->perf_event.kprobe.func_name);
> ulen = info->perf_event.kprobe.name_len;
> - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
> + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
> &type, &missed);
> if (err)
> return err;
> @@ -3617,7 +3620,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
> info->perf_event.type = BPF_PERF_EVENT_KRETPROBE;
> else
> info->perf_event.type = BPF_PERF_EVENT_KPROBE;
> -
> + info->perf_event.kprobe.name_len = ulen;
> info->perf_event.kprobe.offset = offset;
> info->perf_event.kprobe.missed = missed;
> if (!kallsyms_show_value(current_cred()))
> @@ -3639,7 +3642,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
>
> uname = u64_to_user_ptr(info->perf_event.uprobe.file_name);
> ulen = info->perf_event.uprobe.name_len;
> - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
> + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
> &type, NULL);
> if (err)
> return err;
> @@ -3648,6 +3651,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
> info->perf_event.type = BPF_PERF_EVENT_URETPROBE;
> else
> info->perf_event.type = BPF_PERF_EVENT_UPROBE;
> + info->perf_event.uprobe.name_len = ulen;
> info->perf_event.uprobe.offset = offset;
> info->perf_event.uprobe.cookie = event->bpf_cookie;
> return 0;
> @@ -3673,12 +3677,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event,
> {
> char __user *uname;
> u32 ulen;
> + int err;
>
> uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name);
> ulen = info->perf_event.tracepoint.name_len;
> + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL);
> + if (err)
> + return err;
> +
> info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT;
> + info->perf_event.tracepoint.name_len = ulen;
> info->perf_event.tracepoint.cookie = event->bpf_cookie;
> - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL);
> + return 0;
> }
>
> static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
> --
> 2.43.0
>
--
Regards
Yafang
Fix `name_len` field assertions in `bpf_link_info.perf_event` for
kprobe/uprobe/tracepoint to validate correct name size instead of 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info")
Signed-off-by: tyrone-wu <wudevelops@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
---
V4 -> V5: no change
V3 -> V4:
Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
- Split patch into separate kernel and selftest change
tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
index f3932941bbaa..59077f260404 100644
--- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
+++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
@@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
+ ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len");
if (!info.perf_event.kprobe.func_name) {
- ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len");
info.perf_event.kprobe.func_name = ptr_to_u64(&buf);
info.perf_event.kprobe.name_len = sizeof(buf);
goto again;
@@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(err, 0, "cmp_kprobe_func_name");
break;
case BPF_PERF_EVENT_TRACEPOINT:
+ ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len");
if (!info.perf_event.tracepoint.tp_name) {
- ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len");
info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf);
info.perf_event.tracepoint.name_len = sizeof(buf);
goto again;
@@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
case BPF_PERF_EVENT_URETPROBE:
ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+ ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len");
if (!info.perf_event.uprobe.file_name) {
- ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len");
info.perf_event.uprobe.file_name = ptr_to_u64(&buf);
info.perf_event.uprobe.name_len = sizeof(buf);
goto again;
--
2.43.0On Mon, Oct 7, 2024 at 3:51 AM tyrone-wu <wudevelops@gmail.com> wrote:
>
> Fix `name_len` field assertions in `bpf_link_info.perf_event` for
> kprobe/uprobe/tracepoint to validate correct name size instead of 0.
>
> Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
> Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info")
> Signed-off-by: tyrone-wu <wudevelops@gmail.com>
> Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
> ---
> V4 -> V5: no change
>
> V3 -> V4:
> Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
> - Split patch into separate kernel and selftest change
>
> tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
> index f3932941bbaa..59077f260404 100644
> --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
> +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
> @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
>
> ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
>
> + ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len");
> if (!info.perf_event.kprobe.func_name) {
> - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len");
> info.perf_event.kprobe.func_name = ptr_to_u64(&buf);
> info.perf_event.kprobe.name_len = sizeof(buf);
> goto again;
> @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
> ASSERT_EQ(err, 0, "cmp_kprobe_func_name");
> break;
> case BPF_PERF_EVENT_TRACEPOINT:
> + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len");
> if (!info.perf_event.tracepoint.tp_name) {
> - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len");
> info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf);
> info.perf_event.tracepoint.name_len = sizeof(buf);
> goto again;
> @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
> case BPF_PERF_EVENT_URETPROBE:
> ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
>
> + ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len");
> if (!info.perf_event.uprobe.file_name) {
> - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len");
> info.perf_event.uprobe.file_name = ptr_to_u64(&buf);
> info.perf_event.uprobe.name_len = sizeof(buf);
> goto again;
> --
> 2.43.0
>
--
Regards
Yafang
Fix `name_len` field assertions in `bpf_link_info.perf_event` for
kprobe/uprobe/tracepoint to validate correct name size instead of 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/
Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info")
Signed-off-by: tyrone-wu <wudevelops@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
---
V3 -> V4:
Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
- Split patch into separate kernel and selftest change
tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
index f3932941bbaa..59077f260404 100644
--- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
+++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
@@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
+ ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len");
if (!info.perf_event.kprobe.func_name) {
- ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len");
info.perf_event.kprobe.func_name = ptr_to_u64(&buf);
info.perf_event.kprobe.name_len = sizeof(buf);
goto again;
@@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(err, 0, "cmp_kprobe_func_name");
break;
case BPF_PERF_EVENT_TRACEPOINT:
+ ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len");
if (!info.perf_event.tracepoint.tp_name) {
- ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len");
info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf);
info.perf_event.tracepoint.name_len = sizeof(buf);
goto again;
@@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
case BPF_PERF_EVENT_URETPROBE:
ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+ ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len");
if (!info.perf_event.uprobe.file_name) {
- ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len");
info.perf_event.uprobe.file_name = ptr_to_u64(&buf);
info.perf_event.uprobe.name_len = sizeof(buf);
goto again;
--
2.43.0© 2016 - 2024 Red Hat, Inc.