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authorWei Wang <weiwan@google.com>2017-10-13 15:01:08 -0700
committerDavid S. Miller <davem@davemloft.net>2017-10-16 21:06:12 +0100
commit0e80193bd8c1d97654f1a2f45934e7372e9a512e (patch)
treede451403c6ee2bc38dca0eed86a9d0254dc06efe
parent9db9583839b760fc492a7b288edfe2213184a579 (diff)
downloadlinux-0e80193bd8c1d97654f1a2f45934e7372e9a512e.tar.bz2
ipv6: check fn before doing FIB6_SUBTREE(fn)
In fib6_locate(), we need to first make sure fn is not NULL before doing FIB6_SUBTREE(fn) to avoid crash. This fixes the following static checker warning: net/ipv6/ip6_fib.c:1462 fib6_locate() warn: variable dereferenced before check 'fn' (see line 1459) net/ipv6/ip6_fib.c 1458 if (src_len) { 1459 struct fib6_node *subtree = FIB6_SUBTREE(fn); ^^^^^^^^^^^^^^^^ We shifted this dereference 1460 1461 WARN_ON(saddr == NULL); 1462 if (fn && subtree) ^^ before the check for NULL. 1463 fn = fib6_locate_1(subtree, saddr, src_len, 1464 offsetof(struct rt6_info, rt6i_src) Fixes: 66f5d6ce53e6 ("ipv6: replace rwlock with rcu and spinlock in fib6_table") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Wei Wang <weiwan@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv6/ip6_fib.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index c2ecd5ec638a..548af48212fc 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1456,13 +1456,16 @@ struct fib6_node *fib6_locate(struct fib6_node *root,
#ifdef CONFIG_IPV6_SUBTREES
if (src_len) {
- struct fib6_node *subtree = FIB6_SUBTREE(fn);
-
WARN_ON(saddr == NULL);
- if (fn && subtree)
- fn = fib6_locate_1(subtree, saddr, src_len,
+ if (fn) {
+ struct fib6_node *subtree = FIB6_SUBTREE(fn);
+
+ if (subtree) {
+ fn = fib6_locate_1(subtree, saddr, src_len,
offsetof(struct rt6_info, rt6i_src),
exact_match);
+ }
+ }
}
#endif