lkml.org 
[lkml]   [2010]   [Jan]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:x86/urgent] x86: copy_from_user() should not return -EFAULT
Commit-ID:  409d02ef6d74f5e91f5ea4c587b2ee1375f106fc
Gitweb: http://git.kernel.org/tip/409d02ef6d74f5e91f5ea4c587b2ee1375f106fc
Author: Heiko Carstens <heiko.carstens@de.ibm.com>
AuthorDate: Tue, 5 Jan 2010 14:19:11 +0100
Committer: H. Peter Anvin <hpa@zytor.com>
CommitDate: Tue, 5 Jan 2010 13:45:06 -0800

x86: copy_from_user() should not return -EFAULT

Callers of copy_from_user() expect it to return the number of bytes
it could not copy. In no case it is supposed to return -EFAULT.

In case of a detected buffer overflow just return the requested
length. In addition one could think of a memset that would clear
the size of the target object.

[ hpa: code is not in .32 so not needed for -stable ]

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
LKML-Reference: <20100105131911.GC5480@osiris.boeblingen.de.ibm.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
arch/x86/include/asm/uaccess_32.h | 5 ++---
arch/x86/include/asm/uaccess_64.h | 5 ++---
2 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/arch/x86/include/asm/uaccess_32.h b/arch/x86/include/asm/uaccess_32.h
index 0c9825e..088d09f 100644
--- a/arch/x86/include/asm/uaccess_32.h
+++ b/arch/x86/include/asm/uaccess_32.h
@@ -205,14 +205,13 @@ static inline unsigned long __must_check copy_from_user(void *to,
unsigned long n)
{
int sz = __compiletime_object_size(to);
- int ret = -EFAULT;

if (likely(sz == -1 || sz >= n))
- ret = _copy_from_user(to, from, n);
+ n = _copy_from_user(to, from, n);
else
copy_from_user_overflow();

- return ret;
+ return n;
}

long __must_check strncpy_from_user(char *dst, const char __user *src,
diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h
index 46324c6..535e421 100644
--- a/arch/x86/include/asm/uaccess_64.h
+++ b/arch/x86/include/asm/uaccess_64.h
@@ -30,16 +30,15 @@ static inline unsigned long __must_check copy_from_user(void *to,
unsigned long n)
{
int sz = __compiletime_object_size(to);
- int ret = -EFAULT;

might_fault();
if (likely(sz == -1 || sz >= n))
- ret = _copy_from_user(to, from, n);
+ n = _copy_from_user(to, from, n);
#ifdef CONFIG_DEBUG_VM
else
WARN(1, "Buffer overflow detected!\n");
#endif
- return ret;
+ return n;
}

static __always_inline __must_check

\
 
 \ /
  Last update: 2010-01-05 23:19    [from the cache]
©2003-2011 Jasper Spaans. Advertise on this site