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.

Link: https://lkml.kernel.org/r/20241007144911.27693-4-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/all/CAHk-=wivfrF0_zvf+oj6==Sh=-npJooP8chLPEfaFV0oNYTTBA@mail.gmail.com/
Acked-by: Paul Moore <paul@paul-moore.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: Alejandro Colomar <alx@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@gmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matus Jokay <matus.jokay@stuba.sk>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Quentin Monnet <qmo@kernel.org>
Cc: Simon Horman <horms@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/security/lsm_audit.c b/security/lsm_audit.c
index 849e832..9a83529 100644 (file)
--- 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, 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, tsk));
                        }
                }
                break;

diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index e172f18..c9b05be 100644 (file)
--- 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));
+               strscpy(comm, current->comm);
                pr_err("SELinux: %s (%d) set checkreqprot to 1. This is no longer supported.\n",
                       comm, current->pid);
        }