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| author | Xin Long <lucien.xin@gmail.com> | 2020-02-09 21:16:38 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-04-02 15:28:19 +0200 |
| commit | 0a7b397c013322fec975f30012302f694efba2da (patch) | |
| tree | 0f4ca3365a362937238b36ed9e76651d8ad01cd6 /net | |
| parent | cf265c64c91957fd0f1b86b7427028d823966d74 (diff) | |
| download | linux-stable-0a7b397c013322fec975f30012302f694efba2da.tar.gz linux-stable-0a7b397c013322fec975f30012302f694efba2da.tar.bz2 linux-stable-0a7b397c013322fec975f30012302f694efba2da.zip | |
xfrm: add the missing verify_sec_ctx_len check in xfrm_add_acquire
commit a1a7e3a36e01ca6e67014f8cf673cb8e47be5550 upstream.
Without doing verify_sec_ctx_len() check in xfrm_add_acquire(), it may be
out-of-bounds to access uctx->ctx_str with uctx->ctx_len, as noticed by
syz:
BUG: KASAN: slab-out-of-bounds in selinux_xfrm_alloc_user+0x237/0x430
Read of size 768 at addr ffff8880123be9b4 by task syz-executor.1/11650
Call Trace:
dump_stack+0xe8/0x16e
print_address_description.cold.3+0x9/0x23b
kasan_report.cold.4+0x64/0x95
memcpy+0x1f/0x50
selinux_xfrm_alloc_user+0x237/0x430
security_xfrm_policy_alloc+0x5c/0xb0
xfrm_policy_construct+0x2b1/0x650
xfrm_add_acquire+0x21d/0xa10
xfrm_user_rcv_msg+0x431/0x6f0
netlink_rcv_skb+0x15a/0x410
xfrm_netlink_rcv+0x6d/0x90
netlink_unicast+0x50e/0x6a0
netlink_sendmsg+0x8ae/0xd40
sock_sendmsg+0x133/0x170
___sys_sendmsg+0x834/0x9a0
__sys_sendmsg+0x100/0x1e0
do_syscall_64+0xe5/0x660
entry_SYSCALL_64_after_hwframe+0x6a/0xdf
So fix it by adding the missing verify_sec_ctx_len check there.
Fixes: 980ebd25794f ("[IPSEC]: Sync series - acquire insert")
Reported-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/xfrm/xfrm_user.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index 27d94489a091..0b80c7907715 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -2275,6 +2275,9 @@ static int xfrm_add_acquire(struct sk_buff *skb, struct nlmsghdr *nlh, err = verify_newpolicy_info(&ua->policy); if (err) goto free_state; + err = verify_sec_ctx_len(attrs); + if (err) + goto free_state; /* build an XP */ xp = xfrm_policy_construct(net, &ua->policy, attrs, &err); |