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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Julian Orth <ju.orth@gmail.com>,
        Paul Moore <paul@paul-moore.com>
Subject: [PATCH 5.17 051/158] audit,io_uring,io-wq: call __audit_uring_exit for dummy contexts
Date:   Mon, 23 May 2022 19:03:28 +0200
Message-Id: <20220523165839.183895296@linuxfoundation.org>
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References: <20220523165830.581652127@linuxfoundation.org>
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From: Julian Orth <ju.orth@gmail.com>

commit 69e9cd66ae1392437234a63a3a1d60b6655f92ef upstream.

Not calling the function for dummy contexts will cause the context to
not be reset. During the next syscall, this will cause an error in
__audit_syscall_entry:

	WARN_ON(context->context != AUDIT_CTX_UNUSED);
	WARN_ON(context->name_count);
	if (context->context != AUDIT_CTX_UNUSED || context->name_count) {
		audit_panic("unrecoverable error in audit_syscall_entry()");
		return;
	}

These problematic dummy contexts are created via the following call
chain:

       exit_to_user_mode_prepare
    -> arch_do_signal_or_restart
    -> get_signal
    -> task_work_run
    -> tctx_task_work
    -> io_req_task_submit
    -> io_issue_sqe
    -> audit_uring_entry

Cc: stable@vger.kernel.org
Fixes: 5bd2182d58e9 ("audit,io_uring,io-wq: add some basic audit support to io_uring")
Signed-off-by: Julian Orth <ju.orth@gmail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/audit.h |    2 +-
 kernel/auditsc.c      |    6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -339,7 +339,7 @@ static inline void audit_uring_entry(u8
 }
 static inline void audit_uring_exit(int success, long code)
 {
-	if (unlikely(!audit_dummy_context()))
+	if (unlikely(audit_context()))
 		__audit_uring_exit(success, code);
 }
 static inline void audit_syscall_entry(int major, unsigned long a0,
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1959,6 +1959,12 @@ void __audit_uring_exit(int success, lon
 {
 	struct audit_context *ctx = audit_context();
 
+	if (ctx->dummy) {
+		if (ctx->context != AUDIT_CTX_URING)
+			return;
+		goto out;
+	}
+
 	if (ctx->context == AUDIT_CTX_SYSCALL) {
 		/*
 		 * NOTE: See the note in __audit_uring_entry() about the case