netlabel: out of bound access in cipso_v4_validate()

commit d71b7896886345c53ef1d84bda2bc758554f5d61 upstream.

syzkaller found another out of bound access in ip_options_compile(),
or more exactly in cipso_v4_validate()

Fixes: 20e2a8648596 ("cipso: handle CIPSO options correctly when NetLabel is disabled")
Fixes: 446fda4f2682 ("[NetLabel]: CIPSOv4 engine")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov  <dvyukov@google.com>
Cc: Paul Moore <paul@paul-moore.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/include/net/cipso_ipv4.h b/include/net/cipso_ipv4.h
index a6fd939f202d39b0745e0a48ac350cbe9e795648..c8b8852ce9b8910b063c0c0f766cee264e1f44dc 100644 (file)
--- a/include/net/cipso_ipv4.h
+++ b/include/net/cipso_ipv4.h
@@ -302,6 +302,10 @@ static inline int cipso_v4_validate(const struct sk_buff *skb,
        }
 
        for (opt_iter = 6; opt_iter < opt_len;) {
+               if (opt_iter + 1 == opt_len) {
+                       err_offset = opt_iter;
+                       goto out;
+               }
                tag_len = opt[opt_iter + 1];
                if ((tag_len == 0) || (tag_len > (opt_len - opt_iter))) {
                        err_offset = opt_iter + 1;

diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index 69e77c8ff285c74a3743cd10b95cfd04a45bf687..25be314d0e1742053632cb90b5e76d0f5ceb76d9 100644 (file)
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -1645,6 +1645,10 @@ int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option)
                                goto validate_return_locked;
                        }
 
+               if (opt_iter + 1 == opt_len) {
+                       err_offset = opt_iter;
+                       goto validate_return_locked;
+               }
                tag_len = tag[1];
                if (tag_len > (opt_len - opt_iter)) {
                        err_offset = opt_iter + 1;