This is a note to let you know that I've just added the patch titled
selftests/bpf: fix memory leak of lsm_cgroup
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
selftests-bpf-fix-memory-leak-of-lsm_cgroup.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 700384da54942ca59d8a2f53f006ae0738c6e616
Author: Wang Yufen <wangyufen@xxxxxxxxxx>
Date: Tue Nov 15 11:29:40 2022 +0800
selftests/bpf: fix memory leak of lsm_cgroup
[ Upstream commit c453e64cbc9532c0c2edfa999c35d29dad16b8bb ]
kmemleak reports this issue:
unreferenced object 0xffff88810b7835c0 (size 32):
comm "test_progs", pid 270, jiffies 4294969007 (age 1621.315s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
03 00 00 00 03 00 00 00 0f 00 00 00 00 00 00 00 ................
backtrace:
[<00000000376cdeab>] kmalloc_trace+0x27/0x110
[<000000003bcdb3b6>] selinux_sk_alloc_security+0x66/0x110
[<000000003959008f>] security_sk_alloc+0x47/0x80
[<00000000e7bc6668>] sk_prot_alloc+0xbd/0x1a0
[<0000000002d6343a>] sk_alloc+0x3b/0x940
[<000000009812a46d>] unix_create1+0x8f/0x3d0
[<000000005ed0976b>] unix_create+0xa1/0x150
[<0000000086a1d27f>] __sock_create+0x233/0x4a0
[<00000000cffe3a73>] __sys_socket_create.part.0+0xaa/0x110
[<0000000007c63f20>] __sys_socket+0x49/0xf0
[<00000000b08753c8>] __x64_sys_socket+0x42/0x50
[<00000000b56e26b3>] do_syscall_64+0x3b/0x90
[<000000009b4871b8>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
The issue occurs in the following scenarios:
unix_create1()
sk_alloc()
sk_prot_alloc()
security_sk_alloc()
call_int_hook()
hlist_for_each_entry()
entry1->hook.sk_alloc_security
<-- selinux_sk_alloc_security() succeeded,
<-- sk->security alloced here.
entry2->hook.sk_alloc_security
<-- bpf_lsm_sk_alloc_security() failed
goto out_free;
... <-- the sk->security not freed, memleak
The core problem is that the LSM is not yet fully stacked (work is
actively going on in this space) which means that some LSM hooks do
not support multiple LSMs at the same time. To fix, skip the
"EPERM" test when it runs in the environments that already have
non-bpf lsms installed
Fixes: dca85aac8895 ("selftests/bpf: lsm_cgroup functional test")
Signed-off-by: Wang Yufen <wangyufen@xxxxxxxxxx>
Cc: Stanislav Fomichev <sdf@xxxxxxxxxx>
Acked-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
Link: https://lore.kernel.org/r/1668482980-16163-1-git-send-email-wangyufen@xxxxxxxxxx
Signed-off-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/testing/selftests/bpf/prog_tests/lsm_cgroup.c b/tools/testing/selftests/bpf/prog_tests/lsm_cgroup.c
index 1102e4f42d2d..f117bfef68a1 100644
--- a/tools/testing/selftests/bpf/prog_tests/lsm_cgroup.c
+++ b/tools/testing/selftests/bpf/prog_tests/lsm_cgroup.c
@@ -173,10 +173,12 @@ static void test_lsm_cgroup_functional(void)
ASSERT_EQ(query_prog_cnt(cgroup_fd, NULL), 4, "total prog count");
ASSERT_EQ(query_prog_cnt(cgroup_fd2, NULL), 1, "total prog count");
- /* AF_UNIX is prohibited. */
-
fd = socket(AF_UNIX, SOCK_STREAM, 0);
- ASSERT_LT(fd, 0, "socket(AF_UNIX)");
+ if (!(skel->kconfig->CONFIG_SECURITY_APPARMOR
+ || skel->kconfig->CONFIG_SECURITY_SELINUX
+ || skel->kconfig->CONFIG_SECURITY_SMACK))
+ /* AF_UNIX is prohibited. */
+ ASSERT_LT(fd, 0, "socket(AF_UNIX)");
close(fd);
/* AF_INET6 gets default policy (sk_priority). */
@@ -233,11 +235,18 @@ static void test_lsm_cgroup_functional(void)
/* AF_INET6+SOCK_STREAM
* AF_PACKET+SOCK_RAW
+ * AF_UNIX+SOCK_RAW if already have non-bpf lsms installed
* listen_fd
* client_fd
* accepted_fd
*/
- ASSERT_EQ(skel->bss->called_socket_post_create2, 5, "called_create2");
+ if (skel->kconfig->CONFIG_SECURITY_APPARMOR
+ || skel->kconfig->CONFIG_SECURITY_SELINUX
+ || skel->kconfig->CONFIG_SECURITY_SMACK)
+ /* AF_UNIX+SOCK_RAW if already have non-bpf lsms installed */
+ ASSERT_EQ(skel->bss->called_socket_post_create2, 6, "called_create2");
+ else
+ ASSERT_EQ(skel->bss->called_socket_post_create2, 5, "called_create2");
/* start_server
* bind(ETH_P_ALL)
diff --git a/tools/testing/selftests/bpf/progs/lsm_cgroup.c b/tools/testing/selftests/bpf/progs/lsm_cgroup.c
index 4f2d60b87b75..02c11d16b692 100644
--- a/tools/testing/selftests/bpf/progs/lsm_cgroup.c
+++ b/tools/testing/selftests/bpf/progs/lsm_cgroup.c
@@ -7,6 +7,10 @@
char _license[] SEC("license") = "GPL";
+extern bool CONFIG_SECURITY_SELINUX __kconfig __weak;
+extern bool CONFIG_SECURITY_SMACK __kconfig __weak;
+extern bool CONFIG_SECURITY_APPARMOR __kconfig __weak;
+
#ifndef AF_PACKET
#define AF_PACKET 17
#endif
@@ -140,6 +144,10 @@ SEC("lsm_cgroup/sk_alloc_security")
int BPF_PROG(socket_alloc, struct sock *sk, int family, gfp_t priority)
{
called_socket_alloc++;
+ /* if already have non-bpf lsms installed, EPERM will cause memory leak of non-bpf lsms */
+ if (CONFIG_SECURITY_SELINUX || CONFIG_SECURITY_SMACK || CONFIG_SECURITY_APPARMOR)
+ return 1;
+
if (family == AF_UNIX)
return 0; /* EPERM */
