4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sean Tranchetti stranche@codeaurora.org
[ Upstream commit f88b4c01b97e09535505cf3c327fdbce55c27f00 ]
netlbl_unlabel_addrinfo_get() assumes that if it finds the NLBL_UNLABEL_A_IPV4ADDR attribute, it must also have the NLBL_UNLABEL_A_IPV4MASK attribute as well. However, this is not necessarily the case as the current checks in netlbl_unlabel_staticadd() and friends are not sufficent to enforce this.
If passed a netlink message with NLBL_UNLABEL_A_IPV4ADDR, NLBL_UNLABEL_A_IPV6ADDR, and NLBL_UNLABEL_A_IPV6MASK attributes, these functions will all call netlbl_unlabel_addrinfo_get() which will then attempt dereference NULL when fetching the non-existent NLBL_UNLABEL_A_IPV4MASK attribute:
Unable to handle kernel NULL pointer dereference at virtual address 0 Process unlab (pid: 31762, stack limit = 0xffffff80502d8000) Call trace: netlbl_unlabel_addrinfo_get+0x44/0xd8 netlbl_unlabel_staticremovedef+0x98/0xe0 genl_rcv_msg+0x354/0x388 netlink_rcv_skb+0xac/0x118 genl_rcv+0x34/0x48 netlink_unicast+0x158/0x1f0 netlink_sendmsg+0x32c/0x338 sock_sendmsg+0x44/0x60 ___sys_sendmsg+0x1d0/0x2a8 __sys_sendmsg+0x64/0xb4 SyS_sendmsg+0x34/0x4c el0_svc_naked+0x34/0x38 Code: 51001149 7100113f 540000a0 f9401508 (79400108) ---[ end trace f6438a488e737143 ]--- Kernel panic - not syncing: Fatal exception
Signed-off-by: Sean Tranchetti stranche@codeaurora.org
Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/netlabel/netlabel_unlabeled.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/netlabel/netlabel_unlabeled.c +++ b/net/netlabel/netlabel_unlabeled.c @@ -781,7 +781,8 @@ static int netlbl_unlabel_addrinfo_get(s { u32 addr_len;
- if (info->attrs[NLBL_UNLABEL_A_IPV4ADDR]) { + if (info->attrs[NLBL_UNLABEL_A_IPV4ADDR] && + info->attrs[NLBL_UNLABEL_A_IPV4MASK]) { addr_len = nla_len(info->attrs[NLBL_UNLABEL_A_IPV4ADDR]); if (addr_len != sizeof(struct in_addr) && addr_len != nla_len(info->attrs[NLBL_UNLABEL_A_IPV4MASK]))