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| author | Jon Maloy <jon.maloy@ericsson.com> | 2018-03-29 23:20:45 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-04-01 04:19:52 +0200 |
| commit | 7494cfa6d36d1556f17baa012dd93833620783db (patch) | |
| tree | c1905f23eaf0b2aeb7195a78ca378bcb94414251 | |
| parent | tipc: tipc: rename address types in user api (diff) | |
| download | linux-7494cfa6d36d1556f17baa012dd93833620783db.tar.xz linux-7494cfa6d36d1556f17baa012dd93833620783db.zip | |
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>
| -rw-r--r-- | include/uapi/linux/tipc.h | 2 | ||||
| -rw-r--r-- | net/tipc/link.c | 3 |
2 files changed, 3 insertions, 2 deletions
diff --git a/include/uapi/linux/tipc.h b/include/uapi/linux/tipc.h index 156224ac3d74..bf6d28677cfe 100644 --- a/include/uapi/linux/tipc.h +++ b/include/uapi/linux/tipc.h @@ -216,7 +216,7 @@ struct tipc_group_req { #define TIPC_MAX_MEDIA_NAME 16 #define TIPC_MAX_IF_NAME 16 #define TIPC_MAX_BEARER_NAME 32 -#define TIPC_MAX_LINK_NAME 60 +#define TIPC_MAX_LINK_NAME 68 #define SIOCGETLINKNAME SIOCPROTOPRIVATE 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; |