linux-kernel - [PATCH 3/3] signal: lift sigset size check out of do

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Date:   Tue, 22 Aug 2017 02:16:43 +0300
From:   "Dmitry V. Levin" <ldv@...linux.org>
To:     Al Viro <viro@...IV.linux.org.uk>
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] signal: lift sigset size check out of do_sigpending()

As sigsetsize argument of do_sigpending() is not used anywhere else in
that function after the check, remove this argument and move the check
out of do_sigpending() into rt_sigpending() and its compat analog.

Suggested-by: Al Viro <viro@...iv.linux.org.uk>
Signed-off-by: Dmitry V. Levin <ldv@...linux.org>
---
 kernel/signal.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 7d9d82b..894418b 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2629,11 +2629,8 @@ COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
 }
 #endif
 
-static int do_sigpending(void *set, unsigned long sigsetsize)
+static int do_sigpending(sigset_t *set)
 {
-	if (sigsetsize > sizeof(sigset_t))
-		return -EINVAL;
-
 	spin_lock_irq(&current->sighand->siglock);
 	sigorsets(set, &current->pending.signal,
 		  &current->signal->shared_pending.signal);
@@ -2653,7 +2650,12 @@ static int do_sigpending(void *set, unsigned long sigsetsize)
 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
 {
 	sigset_t set;
-	int err = do_sigpending(&set, sigsetsize);
+	int err;
+
+	if (sigsetsize > sizeof(*uset))
+		return -EINVAL;
+
+	err = do_sigpending(&set);
 	if (!err && copy_to_user(uset, &set, sigsetsize))
 		err = -EFAULT;
 	return err;
@@ -2664,7 +2666,12 @@ COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
 		compat_size_t, sigsetsize)
 {
 	sigset_t set;
-	int err = do_sigpending(&set, sigsetsize);
+	int err;
+
+	if (sigsetsize > sizeof(*uset))
+		return -EINVAL;
+
+	err = do_sigpending(&set);
 	if (!err)
 		err = put_compat_sigset(uset, &set, sigsetsize);
 	return err;
@@ -3293,7 +3300,7 @@ SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
 {
 	sigset_t set;
-	int err = do_sigpending(&set, sizeof(set.sig[0]));
+	int err = do_sigpending(&set);
 	if (!err)
 		err = put_user(set.sig[0], set32);
 	return err;
-- 
ldv