From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>,
bridge@lists.linux-foundation.org, GONG@osuosl.org,
netdev@vger.kernel.org, razor@blackwall.org, roopa@nvidia.com,
Florian Westphal <fw@strlen.de>,
"Gustavo A . R . Silva" <gustavoars@kernel.org>,
kadlec@netfilter.org, edumazet@google.com,
coreteam@netfilter.org, netfilter-devel@vger.kernel.org, "GONG,
Ruiqi" <gongruiqi1@huawei.com>,
kuba@kernel.org, pabeni@redhat.com, davem@davemloft.net,
pablo@netfilter.org, Kees Cook <keescook@chromium.org>
Subject: [Bridge] [PATCH AUTOSEL 4.14 6/8] netfilter: ebtables: fix fortify warnings in size_entry_mwt()
Date: Fri, 8 Sep 2023 14:21:25 -0400 [thread overview]
Message-ID: <20230908182127.3461199-6-sashal@kernel.org> (raw)
In-Reply-To: <20230908182127.3461199-1-sashal@kernel.org>
From: "GONG, Ruiqi" <gongruiqi1@huawei.com>
[ Upstream commit a7ed3465daa240bdf01a5420f64336fee879c09d ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 9ff57c0a01990..43db01c05c4d5 100644
--- a/include/uapi/linux/netfilter_bridge/ebtables.h
+++ b/include/uapi/linux/netfilter_bridge/ebtables.h
@@ -172,12 +172,14 @@ 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 84d4b4a0b0536..b5fb880c8a093 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -2071,8 +2071,7 @@ 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;
--
2.40.1
next parent reply other threads:[~2023-09-08 18:21 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230908182127.3461199-1-sashal@kernel.org>
2023-09-08 18:21 ` Sasha Levin [this message]
2023-09-11 9:36 ` [Bridge] [PATCH AUTOSEL 4.14 6/8] netfilter: ebtables: fix fortify warnings in size_entry_mwt() Pavel Machek
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