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authorDaniel Borkmann <dborkman@redhat.com>2013-09-07 17:13:20 +0400
committerDavid S. Miller <davem@davemloft.net>2013-09-12 00:09:59 +0400
commitae7b4e1f213aa659aedf9c6ecad0bf5f0476e1e2 (patch)
treec4bebb0cdc317a32fec9d1eddaf8fa681380e751 /net
parent3bf4b5b11d381fed6a94a7e487e01c8b3bc436b9 (diff)
downloadlinux-ae7b4e1f213aa659aedf9c6ecad0bf5f0476e1e2.tar.xz
net: fib: fib6_add: fix potential NULL pointer dereference
When the kernel is compiled with CONFIG_IPV6_SUBTREES, and we return with an error in fn = fib6_add_1(), then error codes are encoded into the return pointer e.g. ERR_PTR(-ENOENT). In such an error case, we write the error code into err and jump to out, hence enter the if(err) condition. Now, if CONFIG_IPV6_SUBTREES is enabled, we check for: if (pn != fn && pn->leaf == rt) ... if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) ... Since pn is NULL and fn is f.e. ERR_PTR(-ENOENT), then pn != fn evaluates to true and causes a NULL-pointer dereference on further checks on pn. Fix it, by setting both NULL in error case, so that pn != fn already evaluates to false and no further dereference takes place. This was first correctly implemented in 4a287eba2 ("IPv6 routing, NLM_F_* flag support: REPLACE and EXCL flags support, warn about missing CREATE flag"), but the bug got later on introduced by 188c517a0 ("ipv6: return errno pointers consistently for fib6_add_1()"). Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Lin Ming <mlin@ss.pku.edu.cn> Cc: Matti Vaittinen <matti.vaittinen@nsn.com> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Acked-by: Matti Vaittinen <matti.vaittinen@nsn.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv6/ip6_fib.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 73db48eba1c4..5bec666aba61 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -825,9 +825,9 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
fn = fib6_add_1(root, &rt->rt6i_dst.addr, rt->rt6i_dst.plen,
offsetof(struct rt6_info, rt6i_dst), allow_create,
replace_required);
-
if (IS_ERR(fn)) {
err = PTR_ERR(fn);
+ fn = NULL;
goto out;
}