Re: [PATCH -next] netlabel: Fix memory leak in netlbl_mgmt_add_common
From: Paul Moore <paul@paul-moore.com>
Date: 2021-06-10 23:40:25
Also in:
linux-security-module, lkml
On Wed, Jun 9, 2021 at 9:29 PM Liu Shixin [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Hulk Robot reported memory leak in netlbl_mgmt_add_common. The problem is non-freed map in case of netlbl_domhsh_add() failed. BUG: memory leak unreferenced object 0xffff888100ab7080 (size 96): comm "syz-executor537", pid 360, jiffies 4294862456 (age 22.678s) hex dump (first 32 bytes): 05 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ fe 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 ................ backtrace: [<0000000008b40026>] netlbl_mgmt_add_common.isra.0+0xb2a/0x1b40 [<000000003be10950>] netlbl_mgmt_add+0x271/0x3c0 [<00000000c70487ed>] genl_family_rcv_msg_doit.isra.0+0x20e/0x320 [<000000001f2ff614>] genl_rcv_msg+0x2bf/0x4f0 [<0000000089045792>] netlink_rcv_skb+0x134/0x3d0 [<0000000020e96fdd>] genl_rcv+0x24/0x40 [<0000000042810c66>] netlink_unicast+0x4a0/0x6a0 [<000000002e1659f0>] netlink_sendmsg+0x789/0xc70 [<000000006e43415f>] sock_sendmsg+0x139/0x170 [<00000000680a73d7>] ____sys_sendmsg+0x658/0x7d0 [<0000000065cbb8af>] ___sys_sendmsg+0xf8/0x170 [<0000000019932b6c>] __sys_sendmsg+0xd3/0x190 [<00000000643ac172>] do_syscall_64+0x37/0x90 [<000000009b79d6dc>] entry_SYSCALL_64_after_hwframe+0x44/0xae Fixes: 63c416887437 ("netlabel: Add network address selectors to the NetLabel/LSM domain mapping") Reported-by: Hulk Robot <redacted> Signed-off-by: Liu Shixin <redacted> --- net/netlabel/netlabel_mgmt.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-)diff --git a/net/netlabel/netlabel_mgmt.c b/net/netlabel/netlabel_mgmt.c index e664ab990941..e7f00c0f441e 100644 --- a/net/netlabel/netlabel_mgmt.c +++ b/net/netlabel/netlabel_mgmt.c@@ -191,6 +191,12 @@ static int netlbl_mgmt_add_common(struct genl_info *info, entry->family = AF_INET; entry->def.type = NETLBL_NLTYPE_ADDRSELECT; entry->def.addrsel = addrmap; + + ret_val = netlbl_domhsh_add(entry, audit_info); + if (ret_val != 0) { + kfree(map); + goto add_free_addrmap; + } #if IS_ENABLED(CONFIG_IPV6) } else if (info->attrs[NLBL_MGMT_A_IPV6ADDR]) { struct in6_addr *addr;@@ -243,13 +249,19 @@ static int netlbl_mgmt_add_common(struct genl_info *info, entry->family = AF_INET6; entry->def.type = NETLBL_NLTYPE_ADDRSELECT; entry->def.addrsel = addrmap; + + ret_val = netlbl_domhsh_add(entry, audit_info); + if (ret_val != 0) { + kfree(map); + goto add_free_addrmap; + } #endif /* IPv6 */ + } else { + ret_val = netlbl_domhsh_add(entry, audit_info); + if (ret_val != 0) + goto add_free_addrmap; } - ret_val = netlbl_domhsh_add(entry, audit_info); - if (ret_val != 0) - goto add_free_addrmap; - return 0;
Thanks for the report and a fix, although I think there may be a
simpler fix that results in less code duplication; some quick pseudo
code below:
int netlbl_mgmt_add_common(...)
{
void *map_p = NULL;
if (NLBL_MGMT_A_IPV4ADDR) {
struct netlbl_domaddr4_map *map;
map_p = map;
} else if (NLBL_MGMT_A_IPV6ADDR) {
struct netlbl_domaddr4_map *map;
map_p = map;
}
add_free_addrmap:
kfree(map_p);
kfree(addrmap);
}
... this approach would even simplify the error handling after the
netlbl_af{4,6}list_add() calls a bit too (you could jump straight to
add_free_addrmap).
--
paul moore
www.paul-moore.com