diff options
| author | Davide Caratti | 2020-12-03 10:58:21 +0100 |
|---|---|---|
| committer | Jakub Kicinski | 2020-12-03 11:13:21 -0800 |
| commit | 13de4ed9e3a9ccbe54d05f7d5c773f69ecaf6c64 (patch) | |
| tree | 3c31c25a52609be88914c1b5f78aa8d4c06f31f4 | |
| parent | 6392b5b28e0e00171018ecd3ced3554f95b9bb46 (diff) | |
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 <marcelo.leitner@gmail.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Link: https://lore.kernel.org/r/53659f28be8bc336c113b5254dc637cc76bbae91.1606987074.git.dcaratti@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/core/skbuff.c | 3 |
1 files changed, 3 insertions, 0 deletions
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) |