[PATCH AUTOSEL 5.10 22/24] ipvs: Update width of source for ip_vs_sync_conn_options

Sasha Levin
2023-05-04T20:37:30Z

From: Simon Horman <horms@kernel.org>

[ Upstream commit e3478c68f6704638d08f437cbc552ca5970c151a ]

In ip_vs_sync_conn_v0() copy is made to struct ip_vs_sync_conn_options.
That structure looks like this:

struct ip_vs_sync_conn_options {
struct ip_vs_seq in_seq;
struct ip_vs_seq out_seq;
};

The source of the copy is the in_seq field of struct ip_vs_conn. Whose
type is struct ip_vs_seq. Thus we can see that the source - is not as
wide as the amount of data copied, which is the width of struct
ip_vs_sync_conn_option.

The copy is safe because the next field in is another struct ip_vs_seq.
Make use of struct_group() to annotate this.

Flagged by gcc-13 as:

In file included from ./include/linux/string.h:254,
from ./include/linux/bitmap.h:11,
from ./include/linux/cpumask.h:12,
from ./arch/x86/include/asm/paravirt.h:17,
from ./arch/x86/include/asm/cpuid.h:62,
from ./arch/x86/include/asm/processor.h:19,
from ./arch/x86/include/asm/timex.h:5,
from ./include/linux/timex.h:67,
from ./include/linux/time32.h:13,
from ./include/linux/time.h:60,
from ./include/linux/stat.h:19,
from ./include/linux/module.h:13,
from net/netfilter/ipvs/ip_vs_sync.c:38:
In function 'fortify_memcpy_chk',
inlined from 'ip_vs_sync_conn_v0' at net/netfilter/ipvs/ip_vs_sync.c:606:3:
./include/linux/fortify-string.h:529:25: 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]
529 | __read_overflow2_field(q_size_field, size);
|

Compile tested only.

Signed-off-by: Simon Horman <horms@kernel.org>
Reviewed-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/net/ip_vs.h | 6 ++++--
net/netfilter/ipvs/ip_vs_sync.c | 2 +-
2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index d609e957a3ec0..c02c3bb0fe091 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -549,8 +549,10 @@ struct ip_vs_conn {
*/
struct ip_vs_app *app; /* bound ip_vs_app object */
void *app_data; /* Application private data */
- struct ip_vs_seq in_seq; /* incoming seq. struct */
- struct ip_vs_seq out_seq; /* outgoing seq. struct */
+ struct_group(sync_conn_opt,
+ struct ip_vs_seq in_seq; /* incoming seq. struct */
+ struct ip_vs_seq out_seq; /* outgoing seq. struct */
+ );

const struct ip_vs_pe *pe;
char *pe_data;
diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c
index daab857c52a80..fc8db03d3efca 100644
--- a/net/netfilter/ipvs/ip_vs_sync.c
+++ b/net/netfilter/ipvs/ip_vs_sync.c
@@ -603,7 +603,7 @@ static void ip_vs_sync_conn_v0(struct netns_ipvs *ipvs, struct ip_vs_conn *cp,
if (cp->flags & IP_VS_CONN_F_SEQ_MASK) {
struct ip_vs_sync_conn_options *opt =
(struct ip_vs_sync_conn_options *)&s[1];
- memcpy(opt, &cp->in_seq, sizeof(*opt));
+ memcpy(opt, &cp->sync_conn_opt, sizeof(*opt));
}

m->nr_conns++;
--
2.39.2