From: Helge Deller <[email protected]>

[ Upstream commit a089e3fd5a82aea20f3d9ec4caa5f4c65cc2cfcc ]

The kernel signalfd4() syscall returns different error codes when called
either in compat or native mode.  This behaviour makes correct emulation
in qemu and testing programs like LTP more complicated.

Fix the code to always return -in both modes- EFAULT for unaccessible user
memory, and EINVAL when called with an invalid signal mask.

Signed-off-by: Helge Deller <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Laurent Vivier <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 fs/signalfd.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/signalfd.c b/fs/signalfd.c
index 44b6845b071c3..5b78719be4455 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -314,9 +314,10 @@ SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, 
user_mask,
 {
        sigset_t mask;
 
-       if (sizemask != sizeof(sigset_t) ||
-           copy_from_user(&mask, user_mask, sizeof(mask)))
+       if (sizemask != sizeof(sigset_t))
                return -EINVAL;
+       if (copy_from_user(&mask, user_mask, sizeof(mask)))
+               return -EFAULT;
        return do_signalfd4(ufd, &mask, flags);
 }
 
@@ -325,9 +326,10 @@ SYSCALL_DEFINE3(signalfd, int, ufd, sigset_t __user *, 
user_mask,
 {
        sigset_t mask;
 
-       if (sizemask != sizeof(sigset_t) ||
-           copy_from_user(&mask, user_mask, sizeof(mask)))
+       if (sizemask != sizeof(sigset_t))
                return -EINVAL;
+       if (copy_from_user(&mask, user_mask, sizeof(mask)))
+               return -EFAULT;
        return do_signalfd4(ufd, &mask, 0);
 }
 
-- 
2.25.1

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