diff mbox series

[111/165] fs/signalfd.c: fix inconsistent return codes for signalfd4

Message ID 20200812013604.wh3wjni1o%akpm@linux-foundation.org (mailing list archive)
State New, archived
Headers show
Series [001/165] percpu: return number of released bytes from pcpu_free_area() | expand

Commit Message

Andrew Morton Aug. 12, 2020, 1:36 a.m. UTC 
From: Helge Deller <deller@gmx.de>
Subject: fs/signalfd.c: fix inconsistent return codes for signalfd4

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.

Link: http://lkml.kernel.org/r/20200530100707.GA10159@ls3530.fritz.box
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/signalfd.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)
diff mbox series

Patch

--- a/fs/signalfd.c~fs-signalfdc-fix-inconsistent-return-codes-for-signalfd4
+++ a/fs/signalfd.c
@@ -314,9 +314,10 @@  SYSCALL_DEFINE4(signalfd4, int, ufd, sig
 {
 	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, sigs
 {
 	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);
 }