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| author | Xin Long <lucien.xin@gmail.com> | 2019-03-20 14:49:38 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-03-20 11:09:47 -0700 |
| commit | ef82bcfa671b9a635bab5fa669005663d8b177c5 (patch) | |
| tree | ad226efc0e220034faa6f67bf2f40af834119bbd | |
| parent | 1c87e79a002f6a159396138cd3f3ab554a2a8887 (diff) | |
| download | linux-ef82bcfa671b9a635bab5fa669005663d8b177c5.tar.gz linux-ef82bcfa671b9a635bab5fa669005663d8b177c5.tar.bz2 linux-ef82bcfa671b9a635bab5fa669005663d8b177c5.zip | |
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>
| -rw-r--r-- | net/sctp/socket.c | 12 |
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; } |