[PATCH AUTOSEL 6.11 042/244] tipc: guard against string buffer overrun

Sasha Levin
2024-09-25T11:38:10Z

From: Simon Horman <horms@kernel.org>

[ Upstream commit 6555a2a9212be6983d2319d65276484f7c5f431a ]

Smatch reports that copying media_name and if_name to name_parts may
overwrite the destination.

.../bearer.c:166 bearer_name_validate() error: strcpy() 'media_name' too large for 'name_parts->media_name' (32 vs 16)
.../bearer.c:167 bearer_name_validate() error: strcpy() 'if_name' too large for 'name_parts->if_name' (1010102 vs 16)

This does seem to be the case so guard against this possibility by using
strscpy() and failing if truncation occurs.

Introduced by commit b97bf3fd8f6a ("[TIPC] Initial merge")

Compile tested only.

Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20240801-tipic-overrun-v2-1-c5b869d1f074@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/tipc/bearer.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index 5a526ebafeb4b..3c9e25f6a1d22 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -163,8 +163,12 @@ static int bearer_name_validate(const char *name,

/* return bearer name components, if necessary */
if (name_parts) {
- strcpy(name_parts->media_name, media_name);
- strcpy(name_parts->if_name, if_name);
+ if (strscpy(name_parts->media_name, media_name,
+ TIPC_MAX_MEDIA_NAME) < 0)
+ return 0;
+ if (strscpy(name_parts->if_name, if_name,
+ TIPC_MAX_IF_NAME) < 0)
+ return 0;
}
return 1;
}
--
2.43.0