signalfd: lift sigmask copyin and size checks to callers of do_signalfd4()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 25 insertions, 25 deletions

diff --git a/fs/signalfd.c b/fs/signalfd.c
index d2187a813376..46e9de097507 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -256,10 +256,8 @@ static const struct file_operations signalfd_fops = {
         .llseek         = noop_llseek,
 };
 
-static int do_signalfd4(int ufd, sigset_t __user *user_mask, size_t sizemask,
-                        int flags)
+static int do_signalfd4(int ufd, sigset_t *mask, int flags)
 {
-        sigset_t sigmask;
         struct signalfd_ctx *ctx;
 
         /* Check the SFD_* constants for consistency.  */
@@ -269,18 +267,15 @@ static int do_signalfd4(int ufd, sigset_t __user *user_mask, size_t sizemask,
         if (flags & ~(SFD_CLOEXEC | SFD_NONBLOCK))
                 return -EINVAL;
 
-        if (sizemask != sizeof(sigset_t) ||
-            copy_from_user(&sigmask, user_mask, sizeof(sigmask)))
-                return -EINVAL;
-        sigdelsetmask(&sigmask, sigmask(SIGKILL) | sigmask(SIGSTOP));
-        signotset(&sigmask);
+        sigdelsetmask(mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
+        signotset(mask);
 
         if (ufd == -1) {
                 ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
                 if (!ctx)
                         return -ENOMEM;
 
-                ctx->sigmask = sigmask;
+                ctx->sigmask = *mask;
 
                 /*
                  * When we call this, the initialization must be complete, since
@@ -300,7 +295,7 @@ static int do_signalfd4(int ufd, sigset_t __user *user_mask, size_t sizemask,
                         return -EINVAL;
                 }
                 spin_lock_irq(&current->sighand->siglock);
-                ctx->sigmask = sigmask;
+                ctx->sigmask = *mask;
                 spin_unlock_irq(&current->sighand->siglock);
 
                 wake_up(&current->sighand->signalfd_wqh);
@@ -313,46 +308,51 @@ static int do_signalfd4(int ufd, sigset_t __user *user_mask, size_t sizemask,
 SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
                 size_t, sizemask, int, flags)
 {
-        return do_signalfd4(ufd, user_mask, sizemask, flags);
+        sigset_t mask;
+
+        if (sizemask != sizeof(sigset_t) ||
+            copy_from_user(&mask, user_mask, sizeof(mask)))
+                return -EINVAL;
+        return do_signalfd4(ufd, &mask, flags);
 }
 
 SYSCALL_DEFINE3(signalfd, int, ufd, sigset_t __user *, user_mask,
                 size_t, sizemask)
 {
-        return do_signalfd4(ufd, user_mask, sizemask, 0);
+        sigset_t mask;
+
+        if (sizemask != sizeof(sigset_t) ||
+            copy_from_user(&mask, user_mask, sizeof(mask)))
+                return -EINVAL;
+        return do_signalfd4(ufd, &mask, 0);
 }
 
 #ifdef CONFIG_COMPAT
 static long do_compat_signalfd4(int ufd,
-                        const compat_sigset_t __user *sigmask,
+                        const compat_sigset_t __user *user_mask,
                         compat_size_t sigsetsize, int flags)
 {
-        sigset_t tmp;
-        sigset_t __user *ksigmask;
+        sigset_t mask;
 
         if (sigsetsize != sizeof(compat_sigset_t))
                 return -EINVAL;
-        if (get_compat_sigset(&tmp, sigmask))
-                return -EFAULT;
-        ksigmask = compat_alloc_user_space(sizeof(sigset_t));
-        if (copy_to_user(ksigmask, &tmp, sizeof(sigset_t)))
+        if (get_compat_sigset(&mask, user_mask))
                 return -EFAULT;
-
-        return do_signalfd4(ufd, ksigmask, sizeof(sigset_t), flags);
+        return do_signalfd4(ufd, &mask, flags);
 }
 
 COMPAT_SYSCALL_DEFINE4(signalfd4, int, ufd,
-                     const compat_sigset_t __user *, sigmask,
+                     const compat_sigset_t __user *, user_mask,
                      compat_size_t, sigsetsize,
                      int, flags)
 {
-        return do_compat_signalfd4(ufd, sigmask, sigsetsize, flags);
+        return do_compat_signalfd4(ufd, user_mask, sigsetsize, flags);
 }
 
 COMPAT_SYSCALL_DEFINE3(signalfd, int, ufd,
-                     const compat_sigset_t __user *,sigmask,
+                     const compat_sigset_t __user *, user_mask,
                      compat_size_t, sigsetsize)
 {
-        return do_compat_signalfd4(ufd, sigmask, sigsetsize, 0);
+        return do_compat_signalfd4(ufd, user_mask, sigsetsize, 0);
 }
 #endif