From: Xin Long <lucien.xin@gmail.com> To: network dev <netdev@vger.kernel.org>, linux-sctp@vger.kernel.org Cc: davem@davemloft.net, Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>, Neil Horman <nhorman@tuxdriver.com>, syzkaller@googlegroups.com Subject: [PATCH net] sctp: use memdup_user instead of vmemdup_user Date: Wed, 20 Mar 2019 14:49:38 +0800 [thread overview] Message-ID: <94e635135533b7469c84b0aa4df59ea7818a486a.1553064578.git.lucien.xin@gmail.com> (raw) 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> --- net/sctp/socket.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 6140471..09ad5b2 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; } -- 2.1.0
WARNING: multiple messages have this Message-ID (diff)
From: Xin Long <lucien.xin@gmail.com> To: network dev <netdev@vger.kernel.org>, linux-sctp@vger.kernel.org Cc: davem@davemloft.net, Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>, Neil Horman <nhorman@tuxdriver.com>, syzkaller@googlegroups.com Subject: [PATCH net] sctp: use memdup_user instead of vmemdup_user Date: Wed, 20 Mar 2019 06:49:38 +0000 [thread overview] Message-ID: <94e635135533b7469c84b0aa4df59ea7818a486a.1553064578.git.lucien.xin@gmail.com> (raw) 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> --- net/sctp/socket.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 6140471..09ad5b2 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; } -- 2.1.0
next reply other threads:[~2019-03-20 6:49 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-03-20 6:49 Xin Long [this message] 2019-03-20 6:49 ` [PATCH net] sctp: use memdup_user instead of vmemdup_user Xin Long 2019-03-20 11:24 ` Neil Horman 2019-03-20 11:24 ` Neil Horman 2019-03-20 18:10 ` David Miller 2019-03-20 18:10 ` David Miller
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