From 21f9f5219401be3815db41e60072a53dadf828b6 Mon Sep 17 00:00:00 2001 From: Matthew Daley Date: Tue, 19 Mar 2013 12:36:47 +0100 Subject: [PATCH] x25: Validate incoming call user data lengths commit c7fd0d48bde943e228e9c28ce971a22d6a1744c4 upstream. X.25 call user data is being copied in its entirety from incoming messages without consideration to the size of the destination buffers, leading to possible buffer overflows. Validate incoming call user data lengths before these copies are performed. It appears this issue was noticed some time ago, however nothing seemed to come of it: see http://www.spinics.net/lists/linux-x25/msg00043.html and commit 8db09f26f912f7c90c764806e804b558da520d4f. Signed-off-by: Matthew Daley Acked-by: Eric Dumazet Tested-by: Andrew Hendry Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby Signed-off-by: Greg Kroah-Hartman --- net/x25/af_x25.c | 6 ++++++ net/x25/x25_in.c | 3 +++ 2 files changed, 9 insertions(+) diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c index 373e14f21a17..8c0346f00e68 100644 --- a/net/x25/af_x25.c +++ b/net/x25/af_x25.c @@ -959,6 +959,12 @@ int x25_rx_call_request(struct sk_buff *skb, struct x25_neigh *nb, goto out_clear_request; skb_pull(skb,len); + /* + * Ensure that the amount of call user data is valid. + */ + if (skb->len > X25_MAX_CUD_LEN) + goto out_clear_request; + /* * Find a listener for the particular address/cud pair. */ diff --git a/net/x25/x25_in.c b/net/x25/x25_in.c index 15de65f04719..b1180cc28669 100644 --- a/net/x25/x25_in.c +++ b/net/x25/x25_in.c @@ -127,6 +127,9 @@ static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametyp * Copy any Call User Data. */ if (skb->len > 0) { + if (skb->len > X25_MAX_CUD_LEN) + goto out_clear; + skb_copy_from_linear_data(skb, x25->calluserdata.cuddata, skb->len); -- 2.39.5