[PATCH 3/3] signal: lift sigset size check out of do_sigpending()

From: Dmitry V. Levin
Date: Mon Aug 21 2017 - 19:16:50 EST


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@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Dmitry V. Levin <ldv@xxxxxxxxxxxx>
---
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