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Commit 085354f9 authored by Al Viro's avatar Al Viro
Browse files

alpha: get rid of tail-zeroing in __copy_user() 



... and adjust copy_from_user() accordingly

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 8630c322

arch/alpha/include/asm/uaccess.h

+5 −4
Original line number Diff line number Diff line
@@ -396,11 +396,12 @@ copy_to_user(void __user *to, const void *from, long n) 
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);

arch/alpha/lib/copy_user.S

+1 −15
Original line number Diff line number Diff line
@@ -124,22 +124,8 @@ $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

arch/alpha/lib/ev6-copy_user.S

+1 −22
Original line number Diff line number Diff line
@@ -227,33 +227,12 @@ $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