From: KP Singh <kpsingh@chromium.org>
To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
linux-security-module@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
James Morris <jmorris@namei.org>,
Anders Roxell <anders.roxell@linaro.org>,
Casey Schaufler <casey@schaufler-ca.com>
Subject: [PATCH bpf] security: Fix hook iteration for secid_to_secctx
Date: Wed, 20 May 2020 14:56:16 +0200 [thread overview]
Message-ID: <20200520125616.193765-1-kpsingh@chromium.org> (raw)
From: KP Singh <kpsingh@google.com>
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>
---
security/security.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/security/security.c b/security/security.c
index 7fed24b9d57e..51de970fbb1e 100644
--- a/security/security.c
+++ b/security/security.c
@@ -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);
--
2.26.2.761.g0e0b3e54be-goog
next reply other threads:[~2020-05-20 12:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-20 12:56 KP Singh [this message]
2020-05-20 15:15 ` [PATCH bpf] security: Fix hook iteration for secid_to_secctx Casey Schaufler
2020-05-21 1:35 ` Alexei Starovoitov
2020-05-21 2:02 ` James Morris
2020-05-21 3:12 ` Alexei Starovoitov
2020-06-19 12:49 ` Ondrej Mosnacek
2020-06-19 13:13 ` KP Singh
2020-06-19 14:16 ` Ondrej Mosnacek
2020-06-21 21:54 ` KP Singh
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