Re: [PATCH net] selinux: add the missing walk_size + len check in selinux_sctp_bind_connect
From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Date: 2019-03-08 17:08:46
Also in:
linux-sctp, selinux
On Sat, Mar 09, 2019 at 12:07:34AM +0800, Xin Long wrote:
As does in __sctp_connect(), when checking addrs in a while loop, after
get the addr len according to sa_family, it's necessary to do the check
walk_size + af->sockaddr_len > addrs_size to make sure it won't access
an out-of-bounds addr.
The same thing is needed in selinux_sctp_bind_connect(), otherwise an
out-of-bounds issue can be triggered:
[14548.772313] BUG: KASAN: slab-out-of-bounds in selinux_sctp_bind_connect+0x1aa/0x1f0
[14548.927083] Call Trace:
[14548.938072] dump_stack+0x9a/0xe9
[14548.953015] print_address_description+0x65/0x22e
[14548.996524] kasan_report.cold.6+0x92/0x1a6
[14549.015335] selinux_sctp_bind_connect+0x1aa/0x1f0
[14549.036947] security_sctp_bind_connect+0x58/0x90
[14549.058142] __sctp_setsockopt_connectx+0x5a/0x150 [sctp]
[14549.081650] sctp_setsockopt.part.24+0x1322/0x3ce0 [sctp]
Fixes: d452930fd3b9 ("selinux: Add SCTP support")
Reported-by: Chunyu Hu <redacted>
Signed-off-by: Xin Long <lucien.xin@gmail.com>Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Paul, how can we get this into -stable trees? SELinux process may be different from -net trees.
quoted hunk ↗ jump to hunk
--- security/selinux/hooks.c | 3 +++ 1 file changed, 3 insertions(+)diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index f0e36c3..dac9bdb 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c@@ -5120,6 +5120,9 @@ static int selinux_sctp_bind_connect(struct sock *sk, int optname, return -EINVAL; } + if (walk_size + len > addrlen) + return -EINVAL; + err = -EINVAL; switch (optname) { /* Bind checks */-- 2.1.0