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| author | GONG, Ruiqi <gongruiqi1@huawei.com> | 2023-08-09 15:45:03 +0800 |
|---|---|---|
| committer | Florian Westphal <fw@strlen.de> | 2023-08-22 15:13:20 +0200 |
| commit | a7ed3465daa240bdf01a5420f64336fee879c09d (patch) | |
| tree | 72c98ae8062442d373bd73a780bc0e55fdd3e9d0 | |
| parent | 43c2817225fce05701f062a996255007481935e2 (diff) | |
| download | linux-a7ed3465daa240bdf01a5420f64336fee879c09d.tar.gz linux-a7ed3465daa240bdf01a5420f64336fee879c09d.tar.bz2 linux-a7ed3465daa240bdf01a5420f64336fee879c09d.zip | |
netfilter: ebtables: fix fortify warnings in size_entry_mwt()
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>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
| -rw-r--r-- | include/uapi/linux/netfilter_bridge/ebtables.h | 14 | ||||
| -rw-r--r-- | 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..aa23479b20b2 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(entry->offsets)); if (state->buf_kern_start) { buf_start = state->buf_kern_start + state->buf_kern_offset; |