sctp: fix copying more bytes than expected in sctp_add_bind_addr

Dmitry reported that sctp_add_bind_addr may read more bytes than
expected in case the parameter is a IPv4 addr supplied by the user
through calls such as sctp_bindx_add(), because it always copies
sizeof(union sctp_addr) while the buffer may be just a struct
sockaddr_in, which is smaller.

This patch then fixes it by limiting the memcpy to the min between the
union size and a (new parameter) provided addr size. Where possible this
parameter still is the size of that union, except for reading from
user-provided buffers, which then it accounts for protocol type.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Marcelo Ricardo Leitner
2016-03-08 10:34:28 -03:00
committed by David S. Miller
parent e2857b8f11
commit 133800d1f0
5 changed files with 15 additions and 9 deletions

View File

@@ -386,7 +386,8 @@ static int sctp_do_bind(struct sock *sk, union sctp_addr *addr, int len)
/* Add the address to the bind address list.
* Use GFP_ATOMIC since BHs will be disabled.
*/
ret = sctp_add_bind_addr(bp, addr, SCTP_ADDR_SRC, GFP_ATOMIC);
ret = sctp_add_bind_addr(bp, addr, af->sockaddr_len,
SCTP_ADDR_SRC, GFP_ATOMIC);
/* Copy back into socket for getsockname() use. */
if (!ret) {
@@ -577,6 +578,7 @@ static int sctp_send_asconf_add_ip(struct sock *sk,
af = sctp_get_af_specific(addr->v4.sin_family);
memcpy(&saveaddr, addr, af->sockaddr_len);
retval = sctp_add_bind_addr(bp, &saveaddr,
sizeof(saveaddr),
SCTP_ADDR_NEW, GFP_ATOMIC);
addr_buf += af->sockaddr_len;
}