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| author |   Jacob Wen <jian.w.wen@oracle.com> | 2019-01-31 15:18:56 +0800 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2019-01-31 08:58:46 -0800 |
| commit | 91c524708de6207f59dd3512518d8a1c7b434ee3 (patch) | |
| tree | 5e9c1df39ce270ed192b5dfa534a9a866ff7f9c0 /net/l2tp/l2tp_core.c | |
| parent | Merge branch 'stmmac-fixes' (diff) | |
| download | linux-dev-91c524708de6207f59dd3512518d8a1c7b434ee3.tar.xz linux-dev-91c524708de6207f59dd3512518d8a1c7b434ee3.zip | |
l2tp: copy 4 more bytes to linear part if necessary
The size of L2TPv2 header with all optional fields is 14 bytes.
l2tp_udp_recv_core only moves 10 bytes to the linear part of a
skb. This may lead to l2tp_recv_common read data outside of a skb.
This patch make sure that there is at least 14 bytes in the linear
part of a skb to meet the maximum need of l2tp_udp_recv_core and
l2tp_recv_common. The minimum size of both PPP HDLC-like frame and
Ethernet frame is larger than 14 bytes, so we are safe to do so.
Also remove L2TP_HDR_SIZE_NOSEQ, it is unused now.
Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Suggested-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Jacob Wen <jian.w.wen@oracle.com>
Acked-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/l2tp/l2tp_core.c')
| -rw-r--r-- | net/l2tp/l2tp_core.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index dd5ba0c11ab3..fed6becc5daf 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -83,8 +83,7 @@ #define L2TP_SLFLAG_S 0x40000000 #define L2TP_SL_SEQ_MASK 0x00ffffff -#define L2TP_HDR_SIZE_SEQ 10 -#define L2TP_HDR_SIZE_NOSEQ 6 +#define L2TP_HDR_SIZE_MAX 14 /* Default trace flags */ #define L2TP_DEFAULT_DEBUG_FLAGS 0 @@ -808,7 +807,7 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb) __skb_pull(skb, sizeof(struct udphdr)); /* Short packet? */ - if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) { + if (!pskb_may_pull(skb, L2TP_HDR_SIZE_MAX)) { l2tp_info(tunnel, L2TP_MSG_DATA, "%s: recv short packet (len=%d)\n", tunnel->name, skb->len); |