diff mbox series

[net-next,01/10] netfilter: ebtables: fix fortify warnings in size_entry_mwt()

Message ID 20230822154336.12888-2-fw@strlen.de
State Accepted
Headers show
Series [net-next,01/10] netfilter: ebtables: fix fortify warnings in size_entry_mwt() | expand

Commit Message

Florian Westphal Aug. 22, 2023, 3:43 p.m. UTC
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>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 include/uapi/linux/netfilter_bridge/ebtables.h | 14 ++++++++------
 net/bridge/netfilter/ebtables.c                |  3 +--
 2 files changed, 9 insertions(+), 8 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org Aug. 23, 2023, 2 a.m. UTC | #1
Hello:

This series was applied to netdev/net-next.git (main)
by Florian Westphal <fw@strlen.de>:

On Tue, 22 Aug 2023 17:43:22 +0200 you 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);
>       |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> [...]

Here is the summary with links:
  - [net-next,01/10] netfilter: ebtables: fix fortify warnings in size_entry_mwt()
    https://git.kernel.org/netdev/net-next/c/a7ed3465daa2
  - [net-next,02/10] netfilter: ebtables: replace zero-length array members
    https://git.kernel.org/netdev/net-next/c/a2f02c9920b2
  - [net-next,03/10] netfilter: ipset: refactor deprecated strncpy
    https://git.kernel.org/netdev/net-next/c/e53314034b23
  - [net-next,04/10] netfilter: nf_tables: refactor deprecated strncpy
    https://git.kernel.org/netdev/net-next/c/6cdd75a4a66b
  - [net-next,05/10] netfilter: nf_tables: refactor deprecated strncpy
    https://git.kernel.org/netdev/net-next/c/7457af8bf994
  - [net-next,06/10] netfilter: nft_osf: refactor deprecated strncpy
    https://git.kernel.org/netdev/net-next/c/6d87a4eae89e
  - [net-next,07/10] netfilter: nft_meta: refactor deprecated strncpy
    https://git.kernel.org/netdev/net-next/c/ad156c23d65c
  - [net-next,08/10] netfilter: x_tables: refactor deprecated strncpy
    https://git.kernel.org/netdev/net-next/c/06f7d3c3f82c
  - [net-next,09/10] netfilter: xtables: refactor deprecated strncpy
    https://git.kernel.org/netdev/net-next/c/aa222dd190d6
  - [net-next,10/10] netfilter: nf_tables: allow loop termination for pending fatal signal
    https://git.kernel.org/netdev/net-next/c/169384fbe851

You are awesome, thank you!
diff mbox series

Patch

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;