ipv6: Fix potential uninit-value access in __ip6_make_skb()
commit 4e13d3a9c25b7080f8a619f961e943fe08c2672c upstream.
As it was done in commit fc1092f51567 ("ipv4: Fix uninit-value access in
__ip_make_skb()") for IPv4, check FLOWI_FLAG_KNOWN_NH on fl6->flowi6_flags
instead of testing HDRINCL on the socket to avoid a race condition which
causes uninit-value access.
BUG=b/394276446
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2024-36903 in the Linux kernel.
cos-patch: security-moderate
Fixes: ea30388baebc ("ipv6: Fix an uninit variable access bug in __ip6_make_skb()")
Change-Id: I763fed36354257a72363fe4ccbaf51529cf55aba
Signed-off-by: Shigeru Yoshida <syoshida@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Zhaoyang Li <lizy04@hust.edu.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kernel CVE Triage Automation <cloud-image-kernel-cve-triage-automation@prod.google.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/103524
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Miri Amarilio <mirilio@google.com>
Reviewed-by: He Gao <hegao@google.com>
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index d7f7a71..f7a225d 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1985,7 +1985,8 @@ struct sk_buff *__ip6_make_skb(struct sock *sk,
struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
u8 icmp6_type;
- if (sk->sk_socket->type == SOCK_RAW && !inet_sk(sk)->hdrincl)
+ if (sk->sk_socket->type == SOCK_RAW &&
+ !(fl6->flowi6_flags & FLOWI_FLAG_KNOWN_NH))
icmp6_type = fl6->fl6_icmp_type;
else
icmp6_type = icmp6_hdr(skb)->icmp6_type;
