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authorLinus Torvalds <torvalds@linux-foundation.org>2016-10-14 18:19:05 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-14 18:19:05 -0700
commitb26b5ef5ec7eab0e1d84c5b281e87b2f2a5e0586 (patch)
tree3fd57787765f05a19b85b384bd2a68cb4f9276d4 /arch/arm64
parent87dbe42a16b654e33665756c63e96c0fa73eb003 (diff)
parent2692a71bbd40160165e89d5505c5c28144ec5a42 (diff)
downloadlinux-b26b5ef5ec7eab0e1d84c5b281e87b2f2a5e0586.tar.gz
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull more misc uaccess and vfs updates from Al Viro:
 "The rest of the stuff from -next (more uaccess work) + assorted fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  score: traps: Add missing include file to fix build error
  fs/super.c: don't fool lockdep in freeze_super() and thaw_super() paths
  fs/super.c: fix race between freeze_super() and thaw_super()
  overlayfs: Fix setting IOP_XATTR flag
  iov_iter: kernel-doc import_iovec() and rw_copy_check_uvector()
  blackfin: no access_ok() for __copy_{to,from}_user()
  arm64: don't zero in __copy_from_user{,_inatomic}
  arm: don't zero in __copy_from_user_inatomic()/__copy_from_user()
  arc: don't leak bits of kernel stack into coredump
  alpha: get rid of tail-zeroing in __copy_user()
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/include/asm/uaccess.h10
-rw-r--r--arch/arm64/lib/copy_from_user.S7
2 files changed, 7 insertions, 10 deletions
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index c47257c91b77..bcaf6fba1b65 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -278,14 +278,16 @@ static inline unsigned long __must_check __copy_to_user(void __user *to, const v
 
 static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
 {
+	unsigned long res = n;
 	kasan_check_write(to, n);
 
 	if (access_ok(VERIFY_READ, from, n)) {
 		check_object_size(to, n, false);
-		n = __arch_copy_from_user(to, from, n);
-	} else /* security hole - plug it */
-		memset(to, 0, n);
-	return n;
+		res = __arch_copy_from_user(to, from, n);
+	}
+	if (unlikely(res))
+		memset(to + (n - res), 0, res);
+	return res;
 }
 
 static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_user.S
index 0b90497d4424..4fd67ea03bb0 100644
--- a/arch/arm64/lib/copy_from_user.S
+++ b/arch/arm64/lib/copy_from_user.S
@@ -79,11 +79,6 @@ ENDPROC(__arch_copy_from_user)
 
 	.section .fixup,"ax"
 	.align	2
-9998:
-	sub	x0, end, dst
-9999:
-	strb	wzr, [dst], #1			// zero remaining buffer space
-	cmp	dst, end
-	b.lo	9999b
+9998:	sub	x0, end, dst			// bytes not copied
 	ret
 	.previous