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| author | Matthew Daley <mattjd@gmail.com> | 2011-10-14 18:45:04 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-10-17 19:31:39 -0400 |
| commit | cb101ed2c3c7c0224d16953fe77bfb9d6c2cb9df (patch) | |
| tree | 3d266ac18673ebc85a99e4d10d8d381ff1ebd782 /net/x25/x25_in.c | |
| parent | c7fd0d48bde943e228e9c28ce971a22d6a1744c4 (diff) | |
| download | linux-cb101ed2c3c7c0224d16953fe77bfb9d6c2cb9df.tar.gz | |
x25: Handle undersized/fragmented skbs
There are multiple locations in the X.25 packet layer where a skb is assumed to be of at least a certain size and that all its data is currently available at skb->data. These assumptions are not checked, hence buffer overreads may occur. Use pskb_may_pull to check these minimal size assumptions and ensure that data is available at skb->data when necessary, as well as use skb_copy_bits where needed. Signed-off-by: Matthew Daley <mattjd@gmail.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Andrew Hendry <andrew.hendry@gmail.com> Cc: stable <stable@kernel.org> Acked-by: Andrew Hendry <andrew.hendry@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/x25/x25_in.c')
| -rw-r--r-- | net/x25/x25_in.c | 40 |
1 files changed, 35 insertions, 5 deletions
diff --git a/net/x25/x25_in.c b/net/x25/x25_in.c index 63488fd4885a..a49cd4ec551a 100644 --- a/net/x25/x25_in.c +++ b/net/x25/x25_in.c @@ -107,6 +107,8 @@ static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametyp /* * Parse the data in the frame. */ + if (!pskb_may_pull(skb, X25_STD_MIN_LEN)) + goto out_clear; skb_pull(skb, X25_STD_MIN_LEN); len = x25_parse_address_block(skb, &source_addr, @@ -130,9 +132,8 @@ static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametyp if (skb->len > X25_MAX_CUD_LEN) goto out_clear; - skb_copy_from_linear_data(skb, - x25->calluserdata.cuddata, - skb->len); + skb_copy_bits(skb, 0, x25->calluserdata.cuddata, + skb->len); x25->calluserdata.cudlength = skb->len; } if (!sock_flag(sk, SOCK_DEAD)) @@ -140,6 +141,9 @@ static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametyp break; } case X25_CLEAR_REQUEST: + if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2)) + goto out_clear; + x25_write_internal(sk, X25_CLEAR_CONFIRMATION); x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]); break; @@ -167,6 +171,9 @@ static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametyp switch (frametype) { case X25_CLEAR_REQUEST: + if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2)) + goto out_clear; + x25_write_internal(sk, X25_CLEAR_CONFIRMATION); x25_disconnect(sk, 0, skb->data[3], skb->data[4]); break; @@ -180,6 +187,11 @@ static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametyp } return 0; + +out_clear: + x25_write_internal(sk, X25_CLEAR_REQUEST); + x25_start_t23timer(sk); + return 0; } /* @@ -209,6 +221,9 @@ static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametyp break; case X25_CLEAR_REQUEST: + if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2)) + goto out_clear; + x25_write_internal(sk, X25_CLEAR_CONFIRMATION); x25_disconnect(sk, 0, skb->data[3], skb->data[4]); break; @@ -307,6 +322,12 @@ static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametyp } return queued; + +out_clear: + x25_write_internal(sk, X25_CLEAR_REQUEST); + x25->state = X25_STATE_2; + x25_start_t23timer(sk); + return 0; } /* @@ -316,13 +337,13 @@ static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametyp */ static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype) { + struct x25_sock *x25 = x25_sk(sk); + switch (frametype) { case X25_RESET_REQUEST: x25_write_internal(sk, X25_RESET_CONFIRMATION); case X25_RESET_CONFIRMATION: { - struct x25_sock *x25 = x25_sk(sk); - x25_stop_timer(sk); x25->condition = 0x00; x25->va = 0; @@ -334,6 +355,9 @@ static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametyp break; } case X25_CLEAR_REQUEST: + if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2)) + goto out_clear; + x25_write_internal(sk, X25_CLEAR_CONFIRMATION); x25_disconnect(sk, 0, skb->data[3], skb->data[4]); break; @@ -343,6 +367,12 @@ static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametyp } return 0; + +out_clear: + x25_write_internal(sk, X25_CLEAR_REQUEST); + x25->state = X25_STATE_2; + x25_start_t23timer(sk); + return 0; } /* Higher level upcall for a LAPB frame */ |