[PATCH 003/109] kernel: open-code sys_rt_sigpending() in sys_sigpending()

From: Dominik Brodowski
Date: Thu Mar 29 2018 - 07:27:39 EST


A similar but not fully equivalent code path is already open-coded
three times (in sys_rt_sigpending and in the two compat stubs), so
do it a fourth time here.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@xxxxxxxxxxxxxxxxxxxxxxxxxx

Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/syscalls.h | 2 +-
kernel/signal.c | 15 ++++++++++++---
2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 0526286a0314..a63e21e7a3af 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -288,7 +288,7 @@ asmlinkage long sys_capset(cap_user_header_t header,
const cap_user_data_t data);
asmlinkage long sys_personality(unsigned int personality);

-asmlinkage long sys_sigpending(old_sigset_t __user *set);
+asmlinkage long sys_sigpending(old_sigset_t __user *uset);
asmlinkage long sys_sigprocmask(int how, old_sigset_t __user *set,
old_sigset_t __user *oset);
asmlinkage long sys_sigaltstack(const struct sigaltstack __user *uss,
diff --git a/kernel/signal.c b/kernel/signal.c
index c6e4c83dc090..985c61749bcf 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3629,11 +3629,20 @@ int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)

/**
* sys_sigpending - examine pending signals
- * @set: where mask of pending signal is returned
+ * @uset: where mask of pending signal is returned
*/
-SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
+SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
{
- return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t));
+ sigset_t set;
+ int err;
+
+ if (sizeof(old_sigset_t) > sizeof(*uset))
+ return -EINVAL;
+
+ err = do_sigpending(&set);
+ if (!err && copy_to_user(uset, &set, sizeof(old_sigset_t)))
+ err = -EFAULT;
+ return err;
}

#ifdef CONFIG_COMPAT
--
2.16.3