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authorXin Long <lucien.xin@gmail.com>2019-03-20 14:49:38 +0800
committerDavid S. Miller <davem@davemloft.net>2019-03-20 11:09:47 -0700
commitef82bcfa671b9a635bab5fa669005663d8b177c5 (patch)
treead226efc0e220034faa6f67bf2f40af834119bbd /net/sctp
parent1c87e79a002f6a159396138cd3f3ab554a2a8887 (diff)
sctp: use memdup_user instead of vmemdup_user
In sctp_setsockopt_bindx()/__sctp_setsockopt_connectx(), it allocates memory with addrs_size which is passed from userspace. We used flag GFP_USER to put some more restrictions on it in Commit cacc06215271 ("sctp: use GFP_USER for user-controlled kmalloc"). However, since Commit c981f254cc82 ("sctp: use vmemdup_user() rather than badly open-coding memdup_user()"), vmemdup_user() has been used, which doesn't check GFP_USER flag when goes to vmalloc_*(). So when addrs_size is a huge value, it could exhaust memory and even trigger oom killer. This patch is to use memdup_user() instead, in which GFP_USER would work to limit the memory allocation with a huge addrs_size. Note we can't fix it by limiting 'addrs_size', as there's no demand for it from RFC. Reported-by: syzbot+ec1b7575afef85a0e5ca@syzkaller.appspotmail.com Fixes: c981f254cc82 ("sctp: use vmemdup_user() rather than badly open-coding memdup_user()") Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sctp')
-rw-r--r--net/sctp/socket.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 011c349d877a..9874e60c9b0d 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -999,7 +999,7 @@ static int sctp_setsockopt_bindx(struct sock *sk,
if (unlikely(addrs_size <= 0))
return -EINVAL;
- kaddrs = vmemdup_user(addrs, addrs_size);
+ kaddrs = memdup_user(addrs, addrs_size);
if (unlikely(IS_ERR(kaddrs)))
return PTR_ERR(kaddrs);
@@ -1007,7 +1007,7 @@ static int sctp_setsockopt_bindx(struct sock *sk,
addr_buf = kaddrs;
while (walk_size < addrs_size) {
if (walk_size + sizeof(sa_family_t) > addrs_size) {
- kvfree(kaddrs);
+ kfree(kaddrs);
return -EINVAL;
}
@@ -1018,7 +1018,7 @@ static int sctp_setsockopt_bindx(struct sock *sk,
* causes the address buffer to overflow return EINVAL.
*/
if (!af || (walk_size + af->sockaddr_len) > addrs_size) {
- kvfree(kaddrs);
+ kfree(kaddrs);
return -EINVAL;
}
addrcnt++;
@@ -1054,7 +1054,7 @@ static int sctp_setsockopt_bindx(struct sock *sk,
}
out:
- kvfree(kaddrs);
+ kfree(kaddrs);
return err;
}
@@ -1329,7 +1329,7 @@ static int __sctp_setsockopt_connectx(struct sock *sk,
if (unlikely(addrs_size <= 0))
return -EINVAL;
- kaddrs = vmemdup_user(addrs, addrs_size);
+ kaddrs = memdup_user(addrs, addrs_size);
if (unlikely(IS_ERR(kaddrs)))
return PTR_ERR(kaddrs);
@@ -1349,7 +1349,7 @@ static int __sctp_setsockopt_connectx(struct sock *sk,
err = __sctp_connect(sk, kaddrs, addrs_size, flags, assoc_id);
out_free:
- kvfree(kaddrs);
+ kfree(kaddrs);
return err;
}