From: Greg Kroah-Hartman <gre...@linuxfoundation.org>
From: Al Viro <v...@zeniv.linux.org.uk>
commit 085354f907969fb3ee33f236368f6e1dd4c74d62 upstream.
... and adjust copy_from_user() accordingly
Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
Cc: Guenter Roeck <li...@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/alpha/include/asm/uaccess.h | 9 +++++----
arch/alpha/lib/copy_user.S | 16 +---------------
arch/alpha/lib/ev6-copy_user.S | 23 +----------------------
3 files changed, 7 insertions(+), 41 deletions(-)
--- a/arch/alpha/include/asm/uaccess.h
+++ b/arch/alpha/include/asm/uaccess.h
@@ -396,11 +396,12 @@ copy_to_user(void __user *to, const void
extern inline long
copy_from_user(void *to, const void __user *from, long n)
{
+ long res = n;
if (likely(__access_ok((unsigned long)from, n, get_fs())))
- n = __copy_tofrom_user_nocheck(to, (__force void *)from, n);
- else
- memset(to, 0, n);
- return n;
+ res = __copy_from_user_inatomic(to, from, n);
+ if (unlikely(res))
+ memset(to + (n - res), 0, res);
+ return res;
}
extern void __do_clear_user(void);
--- a/arch/alpha/lib/copy_user.S
+++ b/arch/alpha/lib/copy_user.S
@@ -126,22 +126,8 @@ $65:
bis $31,$31,$0
$41:
$35:
-$exitout:
- ret $31,($28),1
-
$exitin:
- /* A stupid byte-by-byte zeroing of the rest of the output
- buffer. This cures security holes by never leaving
- random kernel data around to be copied elsewhere. */
-
- mov $0,$1
-$101:
- EXO ( ldq_u $2,0($6) )
- subq $1,1,$1
- mskbl $2,$6,$2
- EXO ( stq_u $2,0($6) )
- addq $6,1,$6
- bgt $1,$101
+$exitout:
ret $31,($28),1
.end __copy_user
--- a/arch/alpha/lib/ev6-copy_user.S
+++ b/arch/alpha/lib/ev6-copy_user.S
@@ -228,33 +228,12 @@ $dirtyentry:
bgt $0,$onebyteloop # U .. .. .. : U L U L
$zerolength:
+$exitin:
$exitout: # Destination for exception recovery(?)
nop # .. .. .. E
nop # .. .. E ..
nop # .. E .. ..
ret $31,($28),1 # L0 .. .. .. : L U L U
-$exitin:
-
- /* A stupid byte-by-byte zeroing of the rest of the output
- buffer. This cures security holes by never leaving
- random kernel data around to be copied elsewhere. */
-
- nop
- nop
- nop
- mov $0,$1
-
-$101:
- EXO ( stb $31,0($6) ) # L
- subq $1,1,$1 # E
- addq $6,1,$6 # E
- bgt $1,$101 # U
-
- nop
- nop
- nop
- ret $31,($28),1 # L0
-
.end __copy_user
EXPORT_SYMBOL(__copy_user)
