include/uapi/linux/netfilter_bridge/ebtables.h | 14 ++++++++------ net/bridge/netfilter/ebtables.c | 3 +-- 2 files changed, 9 insertions(+), 8 deletions(-)
From: "GONG, Ruiqi" <gongruiqi1@huawei.com>
When compiling with gcc 13 and CONFIG_FORTIFY_SOURCE=y, the following
warning appears:
In function ‘fortify_memcpy_chk’,
inlined from ‘size_entry_mwt’ at net/bridge/netfilter/ebtables.c:2118:2:
./include/linux/fortify-string.h:592:25: error: call to ‘__read_overflow2_field’
declared with attribute warning: detected read beyond size of field (2nd parameter);
maybe use struct_group()? [-Werror=attribute-warning]
592 | __read_overflow2_field(q_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The compiler is complaining:
memcpy(&offsets[1], &entry->watchers_offset,
sizeof(offsets) - sizeof(offsets[0]));
where memcpy reads beyong &entry->watchers_offset to copy
{watchers,target,next}_offset altogether into offsets[]. Silence the
warning by wrapping these three up via struct_group().
Signed-off-by: GONG, Ruiqi <gongruiqi1@huawei.com>
---
v2: fix HDRTEST error by replacing struct_group() with __struct_group(),
since it's a uapi header.
include/uapi/linux/netfilter_bridge/ebtables.h | 14 ++++++++------
net/bridge/netfilter/ebtables.c | 3 +--
2 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/include/uapi/linux/netfilter_bridge/ebtables.h b/include/uapi/linux/netfilter_bridge/ebtables.h
index a494cf43a755..b0caad82b693 100644
--- a/include/uapi/linux/netfilter_bridge/ebtables.h
+++ b/include/uapi/linux/netfilter_bridge/ebtables.h
@@ -182,12 +182,14 @@ struct ebt_entry {
unsigned char sourcemsk[ETH_ALEN];
unsigned char destmac[ETH_ALEN];
unsigned char destmsk[ETH_ALEN];
- /* sizeof ebt_entry + matches */
- unsigned int watchers_offset;
- /* sizeof ebt_entry + matches + watchers */
- unsigned int target_offset;
- /* sizeof ebt_entry + matches + watchers + target */
- unsigned int next_offset;
+ __struct_group(/* no tag */, offsets, /* no attrs */,
+ /* sizeof ebt_entry + matches */
+ unsigned int watchers_offset;
+ /* sizeof ebt_entry + matches + watchers */
+ unsigned int target_offset;
+ /* sizeof ebt_entry + matches + watchers + target */
+ unsigned int next_offset;
+ );
unsigned char elems[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
};
diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 757ec46fc45a..5ec66b1ebb64 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -2115,8 +2115,7 @@ static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *ba
return ret;
offsets[0] = sizeof(struct ebt_entry); /* matches come first */
- memcpy(&offsets[1], &entry->watchers_offset,
- sizeof(offsets) - sizeof(offsets[0]));
+ memcpy(&offsets[1], &entry->offsets, sizeof(offsets) - sizeof(offsets[0]));
if (state->buf_kern_start) {
buf_start = state->buf_kern_start + state->buf_kern_offset;
--
2.41.0
On Tue, Aug 08, 2023 at 09:30:38PM +0800, GONG, Ruiqi wrote:
> From: "GONG, Ruiqi" <gongruiqi1@huawei.com>
>
> When compiling with gcc 13 and CONFIG_FORTIFY_SOURCE=y, the following
> warning appears:
>
> In function ‘fortify_memcpy_chk’,
> inlined from ‘size_entry_mwt’ at net/bridge/netfilter/ebtables.c:2118:2:
> ./include/linux/fortify-string.h:592:25: error: call to ‘__read_overflow2_field’
> declared with attribute warning: detected read beyond size of field (2nd parameter);
> maybe use struct_group()? [-Werror=attribute-warning]
> 592 | __read_overflow2_field(q_size_field, size);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> The compiler is complaining:
>
> memcpy(&offsets[1], &entry->watchers_offset,
> sizeof(offsets) - sizeof(offsets[0]));
>
> where memcpy reads beyong &entry->watchers_offset to copy
> {watchers,target,next}_offset altogether into offsets[]. Silence the
> warning by wrapping these three up via struct_group().
>
> Signed-off-by: GONG, Ruiqi <gongruiqi1@huawei.com>
> ---
>
> v2: fix HDRTEST error by replacing struct_group() with __struct_group(),
> since it's a uapi header.
>
> include/uapi/linux/netfilter_bridge/ebtables.h | 14 ++++++++------
> net/bridge/netfilter/ebtables.c | 3 +--
> 2 files changed, 9 insertions(+), 8 deletions(-)
>
> diff --git a/include/uapi/linux/netfilter_bridge/ebtables.h b/include/uapi/linux/netfilter_bridge/ebtables.h
> index a494cf43a755..b0caad82b693 100644
> --- a/include/uapi/linux/netfilter_bridge/ebtables.h
> +++ b/include/uapi/linux/netfilter_bridge/ebtables.h
> @@ -182,12 +182,14 @@ struct ebt_entry {
> unsigned char sourcemsk[ETH_ALEN];
> unsigned char destmac[ETH_ALEN];
> unsigned char destmsk[ETH_ALEN];
> - /* sizeof ebt_entry + matches */
> - unsigned int watchers_offset;
> - /* sizeof ebt_entry + matches + watchers */
> - unsigned int target_offset;
> - /* sizeof ebt_entry + matches + watchers + target */
> - unsigned int next_offset;
> + __struct_group(/* no tag */, offsets, /* no attrs */,
> + /* sizeof ebt_entry + matches */
> + unsigned int watchers_offset;
> + /* sizeof ebt_entry + matches + watchers */
> + unsigned int target_offset;
> + /* sizeof ebt_entry + matches + watchers + target */
> + unsigned int next_offset;
> + );
> unsigned char elems[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
> };
>
> diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
> index 757ec46fc45a..5ec66b1ebb64 100644
> --- a/net/bridge/netfilter/ebtables.c
> +++ b/net/bridge/netfilter/ebtables.c
> @@ -2115,8 +2115,7 @@ static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *ba
> return ret;
>
> offsets[0] = sizeof(struct ebt_entry); /* matches come first */
> - memcpy(&offsets[1], &entry->watchers_offset,
> - sizeof(offsets) - sizeof(offsets[0]));
> + memcpy(&offsets[1], &entry->offsets, sizeof(offsets) - sizeof(offsets[0]));
^^^^^^^^^^^^
You now can replace this ____________________________________|
with just `sizeof(entry->offsets)`
With that change you can add my
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Thank you
--
Gustavo
>
> if (state->buf_kern_start) {
> buf_start = state->buf_kern_start + state->buf_kern_offset;
> --
> 2.41.0
>
On 2023/08/09 0:32, Gustavo A. R. Silva wrote:
>
> [...]
>
>> diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
>> index 757ec46fc45a..5ec66b1ebb64 100644
>> --- a/net/bridge/netfilter/ebtables.c
>> +++ b/net/bridge/netfilter/ebtables.c
>> @@ -2115,8 +2115,7 @@ static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *ba
>> return ret;
>>
>> offsets[0] = sizeof(struct ebt_entry); /* matches come first */
>> - memcpy(&offsets[1], &entry->watchers_offset,
>> - sizeof(offsets) - sizeof(offsets[0]));
>> + memcpy(&offsets[1], &entry->offsets, sizeof(offsets) - sizeof(offsets[0]));
> ^^^^^^^^^^^^
> You now can replace this ____________________________________|
> with just `sizeof(entry->offsets)`
>
> With that change you can add my
> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>
> Thank you
> --
> Gustavo
>
Will do. Thanks for the suggestion & review!
>>
>> if (state->buf_kern_start) {
>> buf_start = state->buf_kern_start + state->buf_kern_offset;
>> --
>> 2.41.0
>>
On August 8, 2023 9:32:50 AM PDT, "Gustavo A. R. Silva" <gustavoars@kernel.org> wrote:
>On Tue, Aug 08, 2023 at 09:30:38PM +0800, GONG, Ruiqi wrote:
>> From: "GONG, Ruiqi" <gongruiqi1@huawei.com>
>>
>> When compiling with gcc 13 and CONFIG_FORTIFY_SOURCE=y, the following
>> warning appears:
>>
>> In function ‘fortify_memcpy_chk’,
>> inlined from ‘size_entry_mwt’ at net/bridge/netfilter/ebtables.c:2118:2:
>> ./include/linux/fortify-string.h:592:25: error: call to ‘__read_overflow2_field’
>> declared with attribute warning: detected read beyond size of field (2nd parameter);
>> maybe use struct_group()? [-Werror=attribute-warning]
>> 592 | __read_overflow2_field(q_size_field, size);
>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>> The compiler is complaining:
>>
>> memcpy(&offsets[1], &entry->watchers_offset,
>> sizeof(offsets) - sizeof(offsets[0]));
>>
>> where memcpy reads beyong &entry->watchers_offset to copy
>> {watchers,target,next}_offset altogether into offsets[]. Silence the
>> warning by wrapping these three up via struct_group().
>>
>> Signed-off-by: GONG, Ruiqi <gongruiqi1@huawei.com>
>> ---
>>
>> v2: fix HDRTEST error by replacing struct_group() with __struct_group(),
>> since it's a uapi header.
>>
>> include/uapi/linux/netfilter_bridge/ebtables.h | 14 ++++++++------
>> net/bridge/netfilter/ebtables.c | 3 +--
>> 2 files changed, 9 insertions(+), 8 deletions(-)
>>
>> diff --git a/include/uapi/linux/netfilter_bridge/ebtables.h b/include/uapi/linux/netfilter_bridge/ebtables.h
>> index a494cf43a755..b0caad82b693 100644
>> --- a/include/uapi/linux/netfilter_bridge/ebtables.h
>> +++ b/include/uapi/linux/netfilter_bridge/ebtables.h
>> @@ -182,12 +182,14 @@ struct ebt_entry {
>> unsigned char sourcemsk[ETH_ALEN];
>> unsigned char destmac[ETH_ALEN];
>> unsigned char destmsk[ETH_ALEN];
>> - /* sizeof ebt_entry + matches */
>> - unsigned int watchers_offset;
>> - /* sizeof ebt_entry + matches + watchers */
>> - unsigned int target_offset;
>> - /* sizeof ebt_entry + matches + watchers + target */
>> - unsigned int next_offset;
>> + __struct_group(/* no tag */, offsets, /* no attrs */,
>> + /* sizeof ebt_entry + matches */
>> + unsigned int watchers_offset;
>> + /* sizeof ebt_entry + matches + watchers */
>> + unsigned int target_offset;
>> + /* sizeof ebt_entry + matches + watchers + target */
>> + unsigned int next_offset;
>> + );
>> unsigned char elems[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
>> };
Actually, looking at what size_entry_mwt() is doing, I think you probably DO want a tag for this and to use a real structure for the manipulations instead of doing array indexing? I dunno. This is a weird function! :)
-Kees
>>
>> diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
>> index 757ec46fc45a..5ec66b1ebb64 100644
>> --- a/net/bridge/netfilter/ebtables.c
>> +++ b/net/bridge/netfilter/ebtables.c
>> @@ -2115,8 +2115,7 @@ static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *ba
>> return ret;
>>
>> offsets[0] = sizeof(struct ebt_entry); /* matches come first */
>> - memcpy(&offsets[1], &entry->watchers_offset,
>> - sizeof(offsets) - sizeof(offsets[0]));
>> + memcpy(&offsets[1], &entry->offsets, sizeof(offsets) - sizeof(offsets[0]));
> ^^^^^^^^^^^^
>You now can replace this ____________________________________|
>with just `sizeof(entry->offsets)`
>
>With that change you can add my
>Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>
>Thank you
>--
>Gustavo
>
>>
>> if (state->buf_kern_start) {
>> buf_start = state->buf_kern_start + state->buf_kern_offset;
>> --
>> 2.41.0
>>
--
Kees Cook
On August 8, 2023 9:32:50 AM PDT, "Gustavo A. R. Silva" <gustavoars@kernel.org> wrote:
>On Tue, Aug 08, 2023 at 09:30:38PM +0800, GONG, Ruiqi wrote:
>> From: "GONG, Ruiqi" <gongruiqi1@huawei.com>
>>
>> When compiling with gcc 13 and CONFIG_FORTIFY_SOURCE=y, the following
>> warning appears:
>>
>> In function ‘fortify_memcpy_chk’,
>> inlined from ‘size_entry_mwt’ at net/bridge/netfilter/ebtables.c:2118:2:
>> ./include/linux/fortify-string.h:592:25: error: call to ‘__read_overflow2_field’
>> declared with attribute warning: detected read beyond size of field (2nd parameter);
>> maybe use struct_group()? [-Werror=attribute-warning]
>> 592 | __read_overflow2_field(q_size_field, size);
>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>> The compiler is complaining:
>>
>> memcpy(&offsets[1], &entry->watchers_offset,
>> sizeof(offsets) - sizeof(offsets[0]));
>>
>> where memcpy reads beyong &entry->watchers_offset to copy
>> {watchers,target,next}_offset altogether into offsets[]. Silence the
>> warning by wrapping these three up via struct_group().
>>
>> Signed-off-by: GONG, Ruiqi <gongruiqi1@huawei.com>
>> ---
>>
>> v2: fix HDRTEST error by replacing struct_group() with __struct_group(),
>> since it's a uapi header.
>>
>> include/uapi/linux/netfilter_bridge/ebtables.h | 14 ++++++++------
>> net/bridge/netfilter/ebtables.c | 3 +--
>> 2 files changed, 9 insertions(+), 8 deletions(-)
>>
>> diff --git a/include/uapi/linux/netfilter_bridge/ebtables.h b/include/uapi/linux/netfilter_bridge/ebtables.h
>> index a494cf43a755..b0caad82b693 100644
>> --- a/include/uapi/linux/netfilter_bridge/ebtables.h
>> +++ b/include/uapi/linux/netfilter_bridge/ebtables.h
>> @@ -182,12 +182,14 @@ struct ebt_entry {
>> unsigned char sourcemsk[ETH_ALEN];
>> unsigned char destmac[ETH_ALEN];
>> unsigned char destmsk[ETH_ALEN];
>> - /* sizeof ebt_entry + matches */
>> - unsigned int watchers_offset;
>> - /* sizeof ebt_entry + matches + watchers */
>> - unsigned int target_offset;
>> - /* sizeof ebt_entry + matches + watchers + target */
>> - unsigned int next_offset;
>> + __struct_group(/* no tag */, offsets, /* no attrs */,
>> + /* sizeof ebt_entry + matches */
>> + unsigned int watchers_offset;
>> + /* sizeof ebt_entry + matches + watchers */
>> + unsigned int target_offset;
>> + /* sizeof ebt_entry + matches + watchers + target */
>> + unsigned int next_offset;
>> + );
>> unsigned char elems[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
While we're here, can we drop this [0] in favor of []?
-Kees
>> };
>>
>> diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
>> index 757ec46fc45a..5ec66b1ebb64 100644
>> --- a/net/bridge/netfilter/ebtables.c
>> +++ b/net/bridge/netfilter/ebtables.c
>> @@ -2115,8 +2115,7 @@ static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *ba
>> return ret;
>>
>> offsets[0] = sizeof(struct ebt_entry); /* matches come first */
>> - memcpy(&offsets[1], &entry->watchers_offset,
>> - sizeof(offsets) - sizeof(offsets[0]));
>> + memcpy(&offsets[1], &entry->offsets, sizeof(offsets) - sizeof(offsets[0]));
> ^^^^^^^^^^^^
>You now can replace this ____________________________________|
>with just `sizeof(entry->offsets)`
>
>With that change you can add my
>Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>
>Thank you
>--
>Gustavo
>
>>
>> if (state->buf_kern_start) {
>> buf_start = state->buf_kern_start + state->buf_kern_offset;
>> --
>> 2.41.0
>>
--
Kees Cook
On 2023/08/09 6:53, Kees Cook wrote:
>
> [...]
>>>
>>> diff --git a/include/uapi/linux/netfilter_bridge/ebtables.h b/include/uapi/linux/netfilter_bridge/ebtables.h
>>> index a494cf43a755..b0caad82b693 100644
>>> --- a/include/uapi/linux/netfilter_bridge/ebtables.h
>>> +++ b/include/uapi/linux/netfilter_bridge/ebtables.h
>>> @@ -182,12 +182,14 @@ struct ebt_entry {
>>> unsigned char sourcemsk[ETH_ALEN];
>>> unsigned char destmac[ETH_ALEN];
>>> unsigned char destmsk[ETH_ALEN];
>>> - /* sizeof ebt_entry + matches */
>>> - unsigned int watchers_offset;
>>> - /* sizeof ebt_entry + matches + watchers */
>>> - unsigned int target_offset;
>>> - /* sizeof ebt_entry + matches + watchers + target */
>>> - unsigned int next_offset;
>>> + __struct_group(/* no tag */, offsets, /* no attrs */,
>>> + /* sizeof ebt_entry + matches */
>>> + unsigned int watchers_offset;
>>> + /* sizeof ebt_entry + matches + watchers */
>>> + unsigned int target_offset;
>>> + /* sizeof ebt_entry + matches + watchers + target */
>>> + unsigned int next_offset;
>>> + );
>>> unsigned char elems[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
>
> While we're here, can we drop this [0] in favor of []?
>
> -Kees
>
There are still quite a lot of zero-element array in
include/uapi/linux/netfilter_bridge/ebtables.h. I will submit another
patch to change them altogether.
>>> };
>>>
>>> diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
>>> index 757ec46fc45a..5ec66b1ebb64 100644
>>> --- a/net/bridge/netfilter/ebtables.c
>>> +++ b/net/bridge/netfilter/ebtables.c
>>> @@ -2115,8 +2115,7 @@ static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *ba
>>> return ret;
>>>
>>> offsets[0] = sizeof(struct ebt_entry); /* matches come first */
>>> - memcpy(&offsets[1], &entry->watchers_offset,
>>> - sizeof(offsets) - sizeof(offsets[0]));
>>> + memcpy(&offsets[1], &entry->offsets, sizeof(offsets) - sizeof(offsets[0]));
>> ^^^^^^^^^^^^
>> You now can replace this ____________________________________|
>> with just `sizeof(entry->offsets)`
>>
>> With that change you can add my
>> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>>
>> Thank you
>> --
>> Gustavo
>>
>>>
>>> if (state->buf_kern_start) {
>>> buf_start = state->buf_kern_start + state->buf_kern_offset;
>>> --
>>> 2.41.0
>>>
>
>
On 2023/08/09 6:53, Kees Cook wrote:
>
> [...]
>>>
>>> diff --git a/include/uapi/linux/netfilter_bridge/ebtables.h b/include/uapi/linux/netfilter_bridge/ebtables.h
>>> index a494cf43a755..b0caad82b693 100644
>>> --- a/include/uapi/linux/netfilter_bridge/ebtables.h
>>> +++ b/include/uapi/linux/netfilter_bridge/ebtables.h
>>> @@ -182,12 +182,14 @@ struct ebt_entry {
>>> unsigned char sourcemsk[ETH_ALEN];
>>> unsigned char destmac[ETH_ALEN];
>>> unsigned char destmsk[ETH_ALEN];
>>> - /* sizeof ebt_entry + matches */
>>> - unsigned int watchers_offset;
>>> - /* sizeof ebt_entry + matches + watchers */
>>> - unsigned int target_offset;
>>> - /* sizeof ebt_entry + matches + watchers + target */
>>> - unsigned int next_offset;
>>> + __struct_group(/* no tag */, offsets, /* no attrs */,
>>> + /* sizeof ebt_entry + matches */
>>> + unsigned int watchers_offset;
>>> + /* sizeof ebt_entry + matches + watchers */
>>> + unsigned int target_offset;
>>> + /* sizeof ebt_entry + matches + watchers + target */
>>> + unsigned int next_offset;
>>> + );
>>> unsigned char elems[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
>
> While we're here, can we drop this [0] in favor of []?
>
> -Kees
>
Look like it could be done. Will do in v3. Thanks!
>>> };
>>>
>>> diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
>>> index 757ec46fc45a..5ec66b1ebb64 100644
>>> --- a/net/bridge/netfilter/ebtables.c
>>> +++ b/net/bridge/netfilter/ebtables.c
>>> @@ -2115,8 +2115,7 @@ static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *ba
>>> return ret;
>>>
>>> offsets[0] = sizeof(struct ebt_entry); /* matches come first */
>>> - memcpy(&offsets[1], &entry->watchers_offset,
>>> - sizeof(offsets) - sizeof(offsets[0]));
>>> + memcpy(&offsets[1], &entry->offsets, sizeof(offsets) - sizeof(offsets[0]));
>> ^^^^^^^^^^^^
>> You now can replace this ____________________________________|
>> with just `sizeof(entry->offsets)`
>>
>> With that change you can add my
>> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>>
>> Thank you
>> --
>> Gustavo
>>
>>>
>>> if (state->buf_kern_start) {
>>> buf_start = state->buf_kern_start + state->buf_kern_offset;
>>> --
>>> 2.41.0
>>>
>
>
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