netdev - [PATCH v3 03/11] security: Replace memcpy() with __get_task

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Message-Id: <20240621022959.9124-4-laoar.shao@gmail.com>
Date: Fri, 21 Jun 2024 10:29:51 +0800
From: Yafang Shao <laoar.shao@...il.com>
To: torvalds@...ux-foundation.org
Cc: ebiederm@...ssion.com,
	alexei.starovoitov@...il.com,
	rostedt@...dmis.org,
	catalin.marinas@....com,
	akpm@...ux-foundation.org,
	penguin-kernel@...ove.sakura.ne.jp,
	linux-mm@...ck.org,
	linux-fsdevel@...r.kernel.org,
	linux-trace-kernel@...r.kernel.org,
	audit@...r.kernel.org,
	linux-security-module@...r.kernel.org,
	selinux@...r.kernel.org,
	bpf@...r.kernel.org,
	netdev@...r.kernel.org,
	dri-devel@...ts.freedesktop.org,
	Yafang Shao <laoar.shao@...il.com>,
	Paul Moore <paul@...l-moore.com>,
	James Morris <jmorris@...ei.org>,
	"Serge E. Hallyn" <serge@...lyn.com>,
	Stephen Smalley <stephen.smalley.work@...il.com>,
	Ondrej Mosnacek <omosnace@...hat.com>
Subject: [PATCH v3 03/11] security: Replace memcpy() with __get_task_comm()

Quoted from Linus [0]:

  selinux never wanted a lock, and never wanted any kind of *consistent*
  result, it just wanted a *stable* result.

Using __get_task_comm() to read the task comm ensures that the name is
always NUL-terminated, regardless of the source string. This approach also
facilitates future extensions to the task comm.

Signed-off-by: Yafang Shao <laoar.shao@...il.com>
LINK: https://lore.kernel.org/all/CAHk-=wivfrF0_zvf+oj6==Sh=-npJooP8chLPEfaFV0oNYTTBA@mail.gmail.com/ [0]
Acked-by: Paul Moore <paul@...l-moore.com>
Cc: James Morris <jmorris@...ei.org>
Cc: "Serge E. Hallyn" <serge@...lyn.com>
Cc: Stephen Smalley <stephen.smalley.work@...il.com>
Cc: Ondrej Mosnacek <omosnace@...hat.com>
---
 security/lsm_audit.c         | 4 ++--
 security/selinux/selinuxfs.c | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/security/lsm_audit.c b/security/lsm_audit.c
index 849e832719e2..a922e4339dd5 100644
--- a/security/lsm_audit.c
+++ b/security/lsm_audit.c
@@ -207,7 +207,7 @@ static void dump_common_audit_data(struct audit_buffer *ab,
 	BUILD_BUG_ON(sizeof(a->u) > sizeof(void *)*2);
 
 	audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current));
-	audit_log_untrustedstring(ab, memcpy(comm, current->comm, sizeof(comm)));
+	audit_log_untrustedstring(ab, __get_task_comm(comm, sizeof(comm), current));
 
 	switch (a->type) {
 	case LSM_AUDIT_DATA_NONE:
@@ -302,7 +302,7 @@ static void dump_common_audit_data(struct audit_buffer *ab,
 				char comm[sizeof(tsk->comm)];
 				audit_log_format(ab, " opid=%d ocomm=", pid);
 				audit_log_untrustedstring(ab,
-				    memcpy(comm, tsk->comm, sizeof(comm)));
+				    __get_task_comm(comm, sizeof(comm), tsk));
 			}
 		}
 		break;
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index e172f182b65c..a8a2ec742576 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -708,7 +708,7 @@ static ssize_t sel_write_checkreqprot(struct file *file, const char __user *buf,
 	if (new_value) {
 		char comm[sizeof(current->comm)];
 
-		memcpy(comm, current->comm, sizeof(comm));
+		__get_task_comm(comm, sizeof(comm), current);
 		pr_err("SELinux: %s (%d) set checkreqprot to 1. This is no longer supported.\n",
 		       comm, current->pid);
 	}
-- 
2.39.1