Besides /proc/self|<pid>, files under /proc/thread-self and
/proc/self|<pid>/task/<tid> also expose host information to the guest
program. This patch adds them to the hijack infrastracture. Note that
is_proc_myself() does not check if the <tid> matches the current thread
and is thus only suitable for procfs files that are identical for all
threads in the same process.
Behavior verified with guest program:
long main_thread_tid;
long gettid() {
return syscall(SYS_gettid);
}
void print_info(const char* cxt, const char* dir) {
char buf[1024];
FILE* fp;
snprintf(buf, sizeof(buf), "%s/cmdline", dir);
fp = fopen(buf, "r");
if (fp == NULL) {
printf("%s: can't open %s\n", cxt, buf);
} else {
fgets(buf, sizeof(buf), fp);
printf("%s %s cmd: %s\n", cxt, dir, buf);
fclose(fp);
}
snprintf(buf, sizeof(buf), "%s/maps", dir);
fp = fopen(buf, "r");
if (fp == NULL) {
printf("%s: can't open %s\n", cxt, buf);
} else {
char seen[128][128];
int n = 0, is_new = 0;
while(fgets(buf, sizeof(buf), fp) != NULL) {
const char* p = strrchr(buf, ' ');
if (p == NULL || *(p + 1) == '\n') {
continue;
}
++p;
is_new = 1;
for (int i = 0; i < n; ++i) {
if (strncmp(p, seen[i], sizeof(seen[i])) == 0) {
is_new = 0;
break;
}
}
if (is_new) {
printf("%s %s map: %s", cxt, dir, p);
if (n < 128) {
strncpy(seen[n], p, sizeof(seen[n]));
seen[n][sizeof(seen[n]) - 1] = '\0';
++n;
}
}
}
fclose(fp);
}
}
void* thread_main(void* _) {
char buf[1024];
print_info("Child", "/proc/thread-self");
snprintf(buf, sizeof(buf), "/proc/%ld/task/%ld", (long) getpid(), main_thread_tid);
print_info("Child", buf);
snprintf(buf, sizeof(buf), "/proc/%ld/task/%ld", (long) getpid(), (long) gettid());
print_info("Child", buf);
return NULL;
}
int main() {
char buf[1024];
pthread_t thread;
int ret;
print_info("Main", "/proc/thread-self");
print_info("Main", "/proc/self");
snprintf(buf, sizeof(buf), "/proc/%ld", (long) getpid());
print_info("Main", buf);
main_thread_tid = gettid();
snprintf(buf, sizeof(buf), "/proc/self/task/%ld", main_thread_tid);
print_info("Main", buf);
snprintf(buf, sizeof(buf), "/proc/%ld/task/%ld", (long) getpid(), main_thread_tid);
print_info("Main", buf);
if ((ret = pthread_create(&thread, NULL, &thread_main, NULL)) < 0) {
printf("ptherad_create failed: %s (%d)\n", strerror(ret), ret);
}
pthread_join(thread, NULL);
return 0;
}
Signed-off-by: Shu-Chun Weng <scw@google.com>
---
linux-user/syscall.c | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 8367cb138d..73fe82bcc7 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -6968,17 +6968,57 @@ static int open_self_auxv(void *cpu_env, int fd)
return 0;
}
+static int consume_task_directories(const char **filename)
+{
+ if (!strncmp(*filename, "task/", strlen("task/"))) {
+ *filename += strlen("task/");
+ if (**filename < '1' || **filename > '9') {
+ return 0;
+ }
+ /*
+ * Don't care about the exact tid.
+ * XXX: this allows opening files under /proc/self|<pid>/task/<n> where
+ * <n> is not a valid thread id. Consider checking if the file
+ * actually exists.
+ */
+ const char *p = *filename + 1;
+ while (*p >= '0' && *p <= '9') {
+ ++p;
+ }
+ if (*p == '/') {
+ *filename = p + 1;
+ return 1;
+ } else {
+ return 0;
+ }
+ }
+ return 1;
+}
+
+/*
+ * Determines if filename refer to a procfs file for the current process or any
+ * thread within the current process. This function should only be used to check
+ * for files that have identical contents in all threads, e.g. exec, maps, etc.
+ */
static int is_proc_myself(const char *filename, const char *entry)
{
if (!strncmp(filename, "/proc/", strlen("/proc/"))) {
filename += strlen("/proc/");
if (!strncmp(filename, "self/", strlen("self/"))) {
filename += strlen("self/");
+ if (!consume_task_directories(&filename)) {
+ return 0;
+ }
+ } else if (!strncmp(filename, "thread-self/", strlen("thread-self/"))) {
+ filename += strlen("thread-self/");
} else if (*filename >= '1' && *filename <= '9') {
char myself[80];
snprintf(myself, sizeof(myself), "%d/", getpid());
if (!strncmp(filename, myself, strlen(myself))) {
filename += strlen(myself);
+ if (!consume_task_directories(&filename)) {
+ return 0;
+ }
} else {
return 0;
}
--
2.23.0.rc1.153.gdeed80330f-goog
Patchew URL: https://patchew.org/QEMU/20190821201921.106902-1-scw@google.com/ Hi, This series seems to have some coding style problems. See output below for more information: Type: series Subject: [Qemu-devel] [PATCH] linux-user: hijack open() for thread directories Message-id: 20190821201921.106902-1-scw@google.com === TEST SCRIPT BEGIN === #!/bin/bash git rev-parse base > /dev/null || exit 0 git config --local diff.renamelimit 0 git config --local diff.renames True git config --local diff.algorithm histogram ./scripts/checkpatch.pl --mailback base.. === TEST SCRIPT END === Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384 From https://github.com/patchew-project/qemu * [new tag] patchew/20190821201921.106902-1-scw@google.com -> patchew/20190821201921.106902-1-scw@google.com Submodule 'capstone' (https://git.qemu.org/git/capstone.git) registered for path 'capstone' Submodule 'dtc' (https://git.qemu.org/git/dtc.git) registered for path 'dtc' Submodule 'roms/QemuMacDrivers' (https://git.qemu.org/git/QemuMacDrivers.git) registered for path 'roms/QemuMacDrivers' Submodule 'roms/SLOF' (https://git.qemu.org/git/SLOF.git) registered for path 'roms/SLOF' Submodule 'roms/edk2' (https://git.qemu.org/git/edk2.git) registered for path 'roms/edk2' Submodule 'roms/ipxe' (https://git.qemu.org/git/ipxe.git) registered for path 'roms/ipxe' Submodule 'roms/openbios' (https://git.qemu.org/git/openbios.git) registered for path 'roms/openbios' Submodule 'roms/openhackware' (https://git.qemu.org/git/openhackware.git) registered for path 'roms/openhackware' Submodule 'roms/opensbi' (https://git.qemu.org/git/opensbi.git) registered for path 'roms/opensbi' Submodule 'roms/qemu-palcode' (https://git.qemu.org/git/qemu-palcode.git) registered for path 'roms/qemu-palcode' Submodule 'roms/seabios' (https://git.qemu.org/git/seabios.git/) registered for path 'roms/seabios' Submodule 'roms/seabios-hppa' (https://git.qemu.org/git/seabios-hppa.git) registered for path 'roms/seabios-hppa' Submodule 'roms/sgabios' (https://git.qemu.org/git/sgabios.git) registered for path 'roms/sgabios' Submodule 'roms/skiboot' (https://git.qemu.org/git/skiboot.git) registered for path 'roms/skiboot' Submodule 'roms/u-boot' (https://git.qemu.org/git/u-boot.git) registered for path 'roms/u-boot' Submodule 'roms/u-boot-sam460ex' (https://git.qemu.org/git/u-boot-sam460ex.git) registered for path 'roms/u-boot-sam460ex' Submodule 'slirp' (https://git.qemu.org/git/libslirp.git) registered for path 'slirp' Submodule 'tests/fp/berkeley-softfloat-3' (https://git.qemu.org/git/berkeley-softfloat-3.git) registered for path 'tests/fp/berkeley-softfloat-3' Submodule 'tests/fp/berkeley-testfloat-3' (https://git.qemu.org/git/berkeley-testfloat-3.git) registered for path 'tests/fp/berkeley-testfloat-3' Submodule 'ui/keycodemapdb' (https://git.qemu.org/git/keycodemapdb.git) registered for path 'ui/keycodemapdb' Cloning into 'capstone'... Submodule path 'capstone': checked out '22ead3e0bfdb87516656453336160e0a37b066bf' Cloning into 'dtc'... Submodule path 'dtc': checked out '88f18909db731a627456f26d779445f84e449536' Cloning into 'roms/QemuMacDrivers'... Submodule path 'roms/QemuMacDrivers': checked out '90c488d5f4a407342247b9ea869df1c2d9c8e266' Cloning into 'roms/SLOF'... Submodule path 'roms/SLOF': checked out '7bfe584e321946771692711ff83ad2b5850daca7' Cloning into 'roms/edk2'... Submodule path 'roms/edk2': checked out '20d2e5a125e34fc8501026613a71549b2a1a3e54' Submodule 'SoftFloat' (https://github.com/ucb-bar/berkeley-softfloat-3.git) registered for path 'ArmPkg/Library/ArmSoftFloatLib/berkeley-softfloat-3' Submodule 'CryptoPkg/Library/OpensslLib/openssl' (https://github.com/openssl/openssl) registered for path 'CryptoPkg/Library/OpensslLib/openssl' Cloning into 'ArmPkg/Library/ArmSoftFloatLib/berkeley-softfloat-3'... Submodule path 'roms/edk2/ArmPkg/Library/ArmSoftFloatLib/berkeley-softfloat-3': checked out 'b64af41c3276f97f0e181920400ee056b9c88037' Cloning into 'CryptoPkg/Library/OpensslLib/openssl'... Submodule path 'roms/edk2/CryptoPkg/Library/OpensslLib/openssl': checked out '50eaac9f3337667259de725451f201e784599687' Submodule 'boringssl' (https://boringssl.googlesource.com/boringssl) registered for path 'boringssl' Submodule 'krb5' (https://github.com/krb5/krb5) registered for path 'krb5' Submodule 'pyca.cryptography' (https://github.com/pyca/cryptography.git) registered for path 'pyca-cryptography' Cloning into 'boringssl'... Submodule path 'roms/edk2/CryptoPkg/Library/OpensslLib/openssl/boringssl': checked out '2070f8ad9151dc8f3a73bffaa146b5e6937a583f' Cloning into 'krb5'... Submodule path 'roms/edk2/CryptoPkg/Library/OpensslLib/openssl/krb5': checked out 'b9ad6c49505c96a088326b62a52568e3484f2168' Cloning into 'pyca-cryptography'... Submodule path 'roms/edk2/CryptoPkg/Library/OpensslLib/openssl/pyca-cryptography': checked out '09403100de2f6f1cdd0d484dcb8e620f1c335c8f' Cloning into 'roms/ipxe'... Submodule path 'roms/ipxe': checked out 'de4565cbe76ea9f7913a01f331be3ee901bb6e17' Cloning into 'roms/openbios'... Submodule path 'roms/openbios': checked out 'c79e0ecb84f4f1ee3f73f521622e264edd1bf174' Cloning into 'roms/openhackware'... Submodule path 'roms/openhackware': checked out 'c559da7c8eec5e45ef1f67978827af6f0b9546f5' Cloning into 'roms/opensbi'... Submodule path 'roms/opensbi': checked out 'ce228ee0919deb9957192d723eecc8aaae2697c6' Cloning into 'roms/qemu-palcode'... Submodule path 'roms/qemu-palcode': checked out 'bf0e13698872450164fa7040da36a95d2d4b326f' Cloning into 'roms/seabios'... Submodule path 'roms/seabios': checked out 'a5cab58e9a3fb6e168aba919c5669bea406573b4' Cloning into 'roms/seabios-hppa'... Submodule path 'roms/seabios-hppa': checked out '0f4fe84658165e96ce35870fd19fc634e182e77b' Cloning into 'roms/sgabios'... Submodule path 'roms/sgabios': checked out 'cbaee52287e5f32373181cff50a00b6c4ac9015a' Cloning into 'roms/skiboot'... Submodule path 'roms/skiboot': checked out '261ca8e779e5138869a45f174caa49be6a274501' Cloning into 'roms/u-boot'... Submodule path 'roms/u-boot': checked out 'd3689267f92c5956e09cc7d1baa4700141662bff' Cloning into 'roms/u-boot-sam460ex'... Submodule path 'roms/u-boot-sam460ex': checked out '60b3916f33e617a815973c5a6df77055b2e3a588' Cloning into 'slirp'... Submodule path 'slirp': checked out '126c04acbabd7ad32c2b018fe10dfac2a3bc1210' Cloning into 'tests/fp/berkeley-softfloat-3'... Submodule path 'tests/fp/berkeley-softfloat-3': checked out 'b64af41c3276f97f0e181920400ee056b9c88037' Cloning into 'tests/fp/berkeley-testfloat-3'... Submodule path 'tests/fp/berkeley-testfloat-3': checked out '5a59dcec19327396a011a17fd924aed4fec416b3' Cloning into 'ui/keycodemapdb'... Submodule path 'ui/keycodemapdb': checked out '6b3d716e2b6472eb7189d3220552280ef3d832ce' Switched to a new branch 'test' 4870b5a linux-user: hijack open() for thread directories === OUTPUT BEGIN === ERROR: Author email address is mangled by the mailing list #2: Author: Shu-Chun Weng via Qemu-devel <qemu-devel@nongnu.org> total: 1 errors, 0 warnings, 57 lines checked Commit 4870b5a2c06d (linux-user: hijack open() for thread directories) has style problems, please review. If any of these errors are false positives report them to the maintainer, see CHECKPATCH in MAINTAINERS. === OUTPUT END === Test command exited with code: 1 The full log is available at http://patchew.org/logs/20190821201921.106902-1-scw@google.com/testing.checkpatch/?type=message. --- Email generated automatically by Patchew [https://patchew.org/]. Please send your feedback to patchew-devel@redhat.com
Ping. Any comments on this? Patchwork:
http://patchwork.ozlabs.org/patch/1151167/
On Wed, Aug 21, 2019 at 1:19 PM Shu-Chun Weng <scw@google.com> wrote:
> Besides /proc/self|<pid>, files under /proc/thread-self and
> /proc/self|<pid>/task/<tid> also expose host information to the guest
> program. This patch adds them to the hijack infrastracture. Note that
> is_proc_myself() does not check if the <tid> matches the current thread
> and is thus only suitable for procfs files that are identical for all
> threads in the same process.
>
> Behavior verified with guest program:
>
> long main_thread_tid;
>
> long gettid() {
> return syscall(SYS_gettid);
> }
>
> void print_info(const char* cxt, const char* dir) {
> char buf[1024];
> FILE* fp;
>
> snprintf(buf, sizeof(buf), "%s/cmdline", dir);
> fp = fopen(buf, "r");
>
> if (fp == NULL) {
> printf("%s: can't open %s\n", cxt, buf);
> } else {
> fgets(buf, sizeof(buf), fp);
> printf("%s %s cmd: %s\n", cxt, dir, buf);
> fclose(fp);
> }
>
> snprintf(buf, sizeof(buf), "%s/maps", dir);
> fp = fopen(buf, "r");
>
> if (fp == NULL) {
> printf("%s: can't open %s\n", cxt, buf);
> } else {
> char seen[128][128];
> int n = 0, is_new = 0;
> while(fgets(buf, sizeof(buf), fp) != NULL) {
> const char* p = strrchr(buf, ' ');
> if (p == NULL || *(p + 1) == '\n') {
> continue;
> }
> ++p;
> is_new = 1;
> for (int i = 0; i < n; ++i) {
> if (strncmp(p, seen[i], sizeof(seen[i])) == 0) {
> is_new = 0;
> break;
> }
> }
> if (is_new) {
> printf("%s %s map: %s", cxt, dir, p);
> if (n < 128) {
> strncpy(seen[n], p, sizeof(seen[n]));
> seen[n][sizeof(seen[n]) - 1] = '\0';
> ++n;
> }
> }
> }
> fclose(fp);
> }
> }
>
> void* thread_main(void* _) {
> char buf[1024];
>
> print_info("Child", "/proc/thread-self");
>
> snprintf(buf, sizeof(buf), "/proc/%ld/task/%ld", (long) getpid(),
> main_thread_tid);
> print_info("Child", buf);
>
> snprintf(buf, sizeof(buf), "/proc/%ld/task/%ld", (long) getpid(), (long)
> gettid());
> print_info("Child", buf);
>
> return NULL;
> }
>
> int main() {
> char buf[1024];
> pthread_t thread;
> int ret;
>
> print_info("Main", "/proc/thread-self");
> print_info("Main", "/proc/self");
>
> snprintf(buf, sizeof(buf), "/proc/%ld", (long) getpid());
> print_info("Main", buf);
>
> main_thread_tid = gettid();
> snprintf(buf, sizeof(buf), "/proc/self/task/%ld", main_thread_tid);
> print_info("Main", buf);
>
> snprintf(buf, sizeof(buf), "/proc/%ld/task/%ld", (long) getpid(),
> main_thread_tid);
> print_info("Main", buf);
>
> if ((ret = pthread_create(&thread, NULL, &thread_main, NULL)) < 0) {
> printf("ptherad_create failed: %s (%d)\n", strerror(ret), ret);
> }
>
> pthread_join(thread, NULL);
> return 0;
> }
>
> Signed-off-by: Shu-Chun Weng <scw@google.com>
> ---
> linux-user/syscall.c | 40 ++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 40 insertions(+)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 8367cb138d..73fe82bcc7 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -6968,17 +6968,57 @@ static int open_self_auxv(void *cpu_env, int fd)
> return 0;
> }
>
> +static int consume_task_directories(const char **filename)
> +{
> + if (!strncmp(*filename, "task/", strlen("task/"))) {
> + *filename += strlen("task/");
> + if (**filename < '1' || **filename > '9') {
> + return 0;
> + }
> + /*
> + * Don't care about the exact tid.
> + * XXX: this allows opening files under /proc/self|<pid>/task/<n>
> where
> + * <n> is not a valid thread id. Consider checking if the
> file
> + * actually exists.
> + */
> + const char *p = *filename + 1;
> + while (*p >= '0' && *p <= '9') {
> + ++p;
> + }
> + if (*p == '/') {
> + *filename = p + 1;
> + return 1;
> + } else {
> + return 0;
> + }
> + }
> + return 1;
> +}
> +
> +/*
> + * Determines if filename refer to a procfs file for the current process
> or any
> + * thread within the current process. This function should only be used
> to check
> + * for files that have identical contents in all threads, e.g. exec,
> maps, etc.
> + */
> static int is_proc_myself(const char *filename, const char *entry)
> {
> if (!strncmp(filename, "/proc/", strlen("/proc/"))) {
> filename += strlen("/proc/");
> if (!strncmp(filename, "self/", strlen("self/"))) {
> filename += strlen("self/");
> + if (!consume_task_directories(&filename)) {
> + return 0;
> + }
> + } else if (!strncmp(filename, "thread-self/",
> strlen("thread-self/"))) {
> + filename += strlen("thread-self/");
> } else if (*filename >= '1' && *filename <= '9') {
> char myself[80];
> snprintf(myself, sizeof(myself), "%d/", getpid());
> if (!strncmp(filename, myself, strlen(myself))) {
> filename += strlen(myself);
> + if (!consume_task_directories(&filename)) {
> + return 0;
> + }
> } else {
> return 0;
> }
> --
> 2.23.0.rc1.153.gdeed80330f-goog
>
>
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