lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date:   Thu,  3 Dec 2020 10:58:21 +0100
From:   Davide Caratti <>
To:     Jakub Kicinski <>,
        Simon Horman <>
Subject: [PATCH net] net: skbuff: ensure LSE is pullable before decrementing the MPLS ttl

skb_mpls_dec_ttl() reads the LSE without ensuring that it is contained in
the skb "linear" area. Fix this calling pskb_may_pull() before reading the
current ttl.

Found by code inspection.

Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC")
Reported-by: Marcelo Ricardo Leitner <>
Signed-off-by: Davide Caratti <>
 net/core/skbuff.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 06c526e0d810..e578544b2cc7 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5786,6 +5786,9 @@ int skb_mpls_dec_ttl(struct sk_buff *skb)
 	if (unlikely(!eth_p_mpls(skb->protocol)))
 		return -EINVAL;
+	if (!pskb_may_pull(skb, skb_network_offset(skb) + MPLS_HLEN))
+		return -ENOMEM;
 	lse = be32_to_cpu(mpls_hdr(skb)->label_stack_entry);
 	ttl = (lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT;
 	if (!--ttl)

Powered by blists - more mailing lists