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Message-ID: <2a901d27-dba5-4ff4-9e47-373c54965253@I-love.SAKURA.ne.jp>
Date: Sat, 3 Feb 2024 19:53:17 +0900
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Subject: [PATCH v2 2/3] tomoyo: replace current->in_execve flag with
 security_execve_abort() hook
Content-Language: en-US
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: Linus Torvalds <torvalds@linux-foundation.org>,
        Eric Biederman <ebiederm@xmission.com>,
        Kees Cook <keescook@chromium.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
        Paul Moore <paul@paul-moore.com>, James Morris <jmorris@namei.org>,
        "Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-security-module <linux-security-module@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
References: <8fafb8e1-b6be-4d08-945f-b464e3a396c8@I-love.SAKURA.ne.jp>
In-Reply-To: <8fafb8e1-b6be-4d08-945f-b464e3a396c8@I-love.SAKURA.ne.jp>
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TOMOYO was using current->in_execve flag in order to restore previous state
when previous execve() request failed. Since security_execve_abort() hook
was added, switch to use it.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
 security/tomoyo/tomoyo.c | 22 ++++++----------------
 1 file changed, 6 insertions(+), 16 deletions(-)

diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c
index 04a92c3d65d4..9da11aaffeb9 100644
--- a/security/tomoyo/tomoyo.c
+++ b/security/tomoyo/tomoyo.c
@@ -18,34 +18,24 @@ struct tomoyo_domain_info *tomoyo_domain(void)
 {
 	struct tomoyo_task *s = tomoyo_task(current);
 
-	if (s->old_domain_info && !current->in_execve) {
-		atomic_dec(&s->old_domain_info->users);
-		s->old_domain_info = NULL;
-	}
 	return s->domain_info;
 }
 
 /**
- * tomoyo_cred_prepare - Target for security_prepare_creds().
- *
- * @new: Pointer to "struct cred".
- * @old: Pointer to "struct cred".
- * @gfp: Memory allocation flags.
+ * tomoyo_execve_abort - Target for security_execve_abort().
  *
- * Returns 0.
+ * @bprm: void
  */
-static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
-			       gfp_t gfp)
+static void tomoyo_execve_abort(void)
 {
-	/* Restore old_domain_info saved by previous execve() request. */
+	/* Restore old_domain_info saved by execve() request. */
 	struct tomoyo_task *s = tomoyo_task(current);
 
-	if (s->old_domain_info && !current->in_execve) {
+	if (s->old_domain_info) {
 		atomic_dec(&s->domain_info->users);
 		s->domain_info = s->old_domain_info;
 		s->old_domain_info = NULL;
 	}
-	return 0;
 }
 
 /**
@@ -554,8 +544,8 @@ static const struct lsm_id tomoyo_lsmid = {
  * registering TOMOYO.
  */
 static struct security_hook_list tomoyo_hooks[] __ro_after_init = {
-	LSM_HOOK_INIT(cred_prepare, tomoyo_cred_prepare),
 	LSM_HOOK_INIT(bprm_committed_creds, tomoyo_bprm_committed_creds),
+	LSM_HOOK_INIT(execve_abort, tomoyo_execve_abort),
 	LSM_HOOK_INIT(task_alloc, tomoyo_task_alloc),
 	LSM_HOOK_INIT(task_free, tomoyo_task_free),
 #ifndef CONFIG_SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
-- 
2.18.4