net: ipmr: limit MRT_TABLE identifiers
Name of pimreg devices are built from following format :
char name[IFNAMSIZ]; // IFNAMSIZ == 16
sprintf(name, "pimreg%u", mrt->id);
We must therefore limit mrt->id to 9 decimal digits
or risk a buffer overflow and a crash.
Restrict table identifiers in [0 ... 999999999] interval.
Reported-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 6168c4d..3eab2b2 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1318,6 +1318,10 @@
if (get_user(v, (u32 __user *)optval))
return -EFAULT;
+ /* "pimreg%u" should not exceed 16 bytes (IFNAMSIZ) */
+ if (v != RT_TABLE_DEFAULT && v >= 1000000000)
+ return -EINVAL;
+
rtnl_lock();
ret = 0;
if (sk == rtnl_dereference(mrt->mroute_sk)) {