Commit 0550cfe8 authored May 20, 2020 by KP Singh Committed by Alexei Starovoitov May 20, 2020

security: Fix hook iteration for secid_to_secctx



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: 98e828a0 ("security: Refactor declaration of LSM hooks")
Fixes: 625236ba ("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

parent 20a785aa

security/security.c

+14 −2

Original line number	Diff line number	Diff line
		@@ -1965,8 +1965,20 @@ 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);

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