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authorDaniel Borkmann <dborkman@redhat.com>2013-09-07 15:13:20 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-10-13 16:08:28 -0700
commit45d268c6b87c0c80fda9960a8b850ee0e82b71dc (patch)
treecb069fa6c34f11b14e00ad123f0fd16f94b3a5fd /net
parent711b8c96842e7e93b01caad6403488498d5cecfa (diff)
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net: fib: fib6_add: fix potential NULL pointer dereference
[ Upstream commit ae7b4e1f213aa659aedf9c6ecad0bf5f0476e1e2 ] 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 2221ff6a308..9c06ecb6556 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, sizeof(struct in6_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;
}