From: KP Singh <kpsingh@google.com>
Date: Wed, 20 May 2020 14:56:16 +0200
Subject: security: Fix hook iteration for secid_to_secctx
Patch-mainline: v5.7-rc7
Git-commit: 0550cfe8c2c6f8e7a4c348b6603a794576db12dd
References: bsc#1177028
secid_to_secctx is not stackable, and since the BPF LSM registers this
hook by default, the call_int_hook logic is not suitable which
"bails-on-fail" and casues issues when other LSMs register this hook and
eventually breaks Audit.
In order to fix this, directly iterate over the security hooks instead
of using call_int_hook as suggested in:
https: //lore.kernel.org/bpf/9d0eb6c6-803a-ff3a-5603-9ad6d9edfc00@schaufler-ca.com/#t
Fixes: 98e828a0650f ("security: Refactor declaration of LSM hooks")
Fixes: 625236ba3832 ("security: Fix the default value of secid_to_secctx hook")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: James Morris <jamorris@linux.microsoft.com>
Link: https://lore.kernel.org/bpf/20200520125616.193765-1-kpsingh@chromium.org
Acked-by: Gary Lin <glin@suse.com>
---
security/security.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
--- a/security/security.c
+++ b/security/security.c
@@ -1933,8 +1933,20 @@ EXPORT_SYMBOL(security_ismaclabel);
int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
- return call_int_hook(secid_to_secctx, -EOPNOTSUPP, secid, secdata,
- seclen);
+ struct security_hook_list *hp;
+ int rc;
+
+ /*
+ * Currently, only one LSM can implement secid_to_secctx (i.e this
+ * LSM hook is not "stackable").
+ */
+ hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
+ rc = hp->hook.secid_to_secctx(secid, secdata, seclen);
+ if (rc != LSM_RET_DEFAULT(secid_to_secctx))
+ return rc;
+ }
+
+ return LSM_RET_DEFAULT(secid_to_secctx);
}
EXPORT_SYMBOL(security_secid_to_secctx);