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authorJon Maloy <jon.maloy@ericsson.com>2018-03-29 23:20:45 +0200
committerDavid S. Miller <davem@davemloft.net>2018-03-31 22:19:52 -0400
commit7494cfa6d36d1556f17baa012dd93833620783db (patch)
treec1905f23eaf0b2aeb7195a78ca378bcb94414251 /net
parent7a74d39cc2927302bc236397c1fdb1fe5be209ce (diff)
tipc: avoid possible string overflow
gcc points out that the combined length of the fixed-length inputs to l->name is larger than the destination buffer size: net/tipc/link.c: In function 'tipc_link_create': net/tipc/link.c:465:26: error: '%s' directive writing up to 32 bytes into a region of size between 26 and 58 [-Werror=format-overflow=] sprintf(l->name, "%s:%s-%s:unknown", self_str, if_name, peer_str); net/tipc/link.c:465:2: note: 'sprintf' output 11 or more bytes (assuming 75) into a destination of size 60 sprintf(l->name, "%s:%s-%s:unknown", self_str, if_name, peer_str); A detailed analysis reveals that the theoretical maximum length of a link name is: max self_str + 1 + max if_name + 1 + max peer_str + 1 + max if_name = 16 + 1 + 15 + 1 + 16 + 1 + 15 = 65 Since we also need space for a trailing zero we now set MAX_LINK_NAME to 68. Just to be on the safe side we also replace the sprintf() call with snprintf(). Fixes: 25b0b9c4e835 ("tipc: handle collisions of 32-bit node address hash values") Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/tipc/link.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/tipc/link.c b/net/tipc/link.c
index 8f2a9496439b..695acb783969 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -462,7 +462,8 @@ bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
sprintf(peer_str, "%x", peer);
}
/* Peer i/f name will be completed by reset/activate message */
- sprintf(l->name, "%s:%s-%s:unknown", self_str, if_name, peer_str);
+ snprintf(l->name, sizeof(l->name), "%s:%s-%s:unknown",
+ self_str, if_name, peer_str);
strcpy(l->if_name, if_name);
l->addr = peer;