This is a note to let you know that I've just added the patch titled
net: skbuff: ensure LSE is pullable before decrementing the MPLS ttl
to the 5.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-skbuff-ensure-lse-is-pullable-before-decrementing-the-mpls-ttl.patch
and it can be found in the queue-5.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Sun Dec 6 10:19:03 AM CET 2020
From: Davide Caratti <dcaratti@xxxxxxxxxx>
Date: Thu, 3 Dec 2020 10:58:21 +0100
Subject: net: skbuff: ensure LSE is pullable before decrementing the MPLS ttl
From: Davide Caratti <dcaratti@xxxxxxxxxx>
[ Upstream commit 13de4ed9e3a9ccbe54d05f7d5c773f69ecaf6c64 ]
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 <marcelo.leitner@xxxxxxxxx>
Signed-off-by: Davide Caratti <dcaratti@xxxxxxxxxx>
Link: https://lore.kernel.org/r/53659f28be8bc336c113b5254dc637cc76bbae91.1606987074.git.dcaratti@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/skbuff.c | 3 +++
1 file changed, 3 insertions(+)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5725,6 +5725,9 @@ 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)
Patches currently in stable-queue which might be from dcaratti@xxxxxxxxxx are
queue-5.9/net-openvswitch-ensure-lse-is-pullable-before-reading-it.patch
queue-5.9/net-skbuff-ensure-lse-is-pullable-before-decrementing-the-mpls-ttl.patch
queue-5.9/mptcp-fix-null-ptr-dereference-on-bad-mpj.patch
queue-5.9/net-sched-act_mpls-ensure-lse-is-pullable-before-reading-it.patch
