signal: make kill_as_cred_perm() return bool

kill_as_cred_perm() already behaves like a boolean function.  Let's
actually declare it as such too.

Link: http://lkml.kernel.org/r/20180602103653.18181-3-christian@brauner.io
Signed-off-by: Christian Brauner <christian@brauner.io>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Morris <james.morris@microsoft.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/signal.c b/kernel/signal.c
index 8a828ba..5b0fb57 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1339,14 +1339,15 @@ static int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
        return error;
 }
 
-static int kill_as_cred_perm(const struct cred *cred,
-                            struct task_struct *target)
+static inline bool kill_as_cred_perm(const struct cred *cred,
+                                    struct task_struct *target)
 {
        const struct cred *pcred = __task_cred(target);
-       if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) &&
-           !uid_eq(cred->uid,  pcred->suid) && !uid_eq(cred->uid,  pcred->uid))
-               return 0;
-       return 1;
+
+       return uid_eq(cred->euid, pcred->suid) ||
+              uid_eq(cred->euid, pcred->uid) ||
+              uid_eq(cred->uid, pcred->suid) ||
+              uid_eq(cred->uid, pcred->uid);
 }
 
 /* like kill_pid_info(), but doesn't use uid/euid of "current" */