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sctp: fix copying more bytes than expected in sctp_add_bind_addr

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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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/net/sctp/structs.h
View File

@ -1098,7 +1098,7 @@ int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
const struct sctp_bind_addr *src,
gfp_t gfp);
int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
__u8 addr_state, gfp_t gfp);
int new_size, __u8 addr_state, gfp_t gfp);
int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
struct sctp_sock *);

14
net/sctp/bind_addr.c
View File

@ -111,7 +111,8 @@ int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
dest->port = src->port;
list_for_each_entry(addr, &src->address_list, list) {
error = sctp_add_bind_addr(dest, &addr->a, 1, gfp);
error = sctp_add_bind_addr(dest, &addr->a, sizeof(addr->a),
1, gfp);
if (error < 0)
break;
}
@ -150,7 +151,7 @@ void sctp_bind_addr_free(struct sctp_bind_addr *bp)
/* Add an address to the bind address list in the SCTP_bind_addr structure. */
int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,
__u8 addr_state, gfp_t gfp)
int new_size, __u8 addr_state, gfp_t gfp)
{
struct sctp_sockaddr_entry *addr;
@ -159,7 +160,7 @@ int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,
if (!addr)
return -ENOMEM;
memcpy(&addr->a, new, sizeof(*new));
memcpy(&addr->a, new, min_t(size_t, sizeof(*new), new_size));
/* Fix up the port if it has not yet been set.
* Both v4 and v6 have the port at the same offset.
@ -291,7 +292,8 @@ int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw_addr_list,
}
af->from_addr_param(&addr, rawaddr, htons(port), 0);
retval = sctp_add_bind_addr(bp, &addr, SCTP_ADDR_SRC, gfp);
retval = sctp_add_bind_addr(bp, &addr, sizeof(addr),
SCTP_ADDR_SRC, gfp);
if (retval) {
/* Can't finish building the list, clean up. */
sctp_bind_addr_clean(bp);
@ -453,8 +455,8 @@ static int sctp_copy_one_addr(struct net *net, struct sctp_bind_addr *dest,
(((AF_INET6 == addr->sa.sa_family) &&
(flags & SCTP_ADDR6_ALLOWED) &&
(flags & SCTP_ADDR6_PEERSUPP))))
error = sctp_add_bind_addr(dest, addr, SCTP_ADDR_SRC,
gfp);
error = sctp_add_bind_addr(dest, addr, sizeof(*addr),
SCTP_ADDR_SRC, gfp);
}
return error;

1
net/sctp/protocol.c
View File

@ -216,6 +216,7 @@ int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *bp,
(copy_flags & SCTP_ADDR6_ALLOWED) &&
(copy_flags & SCTP_ADDR6_PEERSUPP)))) {
error = sctp_add_bind_addr(bp, &addr->a,
sizeof(addr->a),
SCTP_ADDR_SRC, GFP_ATOMIC);
if (error)
goto end_copy;

3
net/sctp/sm_make_chunk.c
View File

@ -1830,7 +1830,8 @@ no_hmac:
/* Also, add the destination address. */
if (list_empty(&retval->base.bind_addr.address_list)) {
sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
SCTP_ADDR_SRC, GFP_ATOMIC);
sizeof(chunk->dest), SCTP_ADDR_SRC,
GFP_ATOMIC);
}
retval->next_tsn = retval->c.initial_tsn;

4
net/sctp/socket.c
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;
}