sparc: Increase portability of strncpy_from_user() implementation. (35c96460) · Commits · 戴 / test

arch/sparc/include/asm/uaccess.h

+3 −0

Original line number	Original line	Diff line number	Diff line
	@@ -6,6 +6,9 @@
	#include <asm/uaccess_32.h>		#include <asm/uaccess_32.h>
	#endif		#endif

			#define user_addr_max() \
			(segment_eq(get_fs(), USER_DS) ? STACK_TOP : ~0UL)

	extern long strncpy_from_user(char dest, const char __user src, long count);		extern long strncpy_from_user(char dest, const char __user src, long count);

	#endif		#endif

arch/sparc/lib/usercopy.c

+27 −5

Original line number	Original line	Diff line number	Diff line
	@@ -3,6 +3,8 @@
	#include <linux/errno.h>		#include <linux/errno.h>
	#include <linux/bug.h>		#include <linux/bug.h>

			#include <asm/byteorder.h>

	void copy_from_user_overflow(void)		void copy_from_user_overflow(void)
	{		{
	WARN(1, "Buffer overflow detected!\n");		WARN(1, "Buffer overflow detected!\n");
	@@ -14,6 +16,8 @@ EXPORT_SYMBOL(copy_from_user_overflow);
	static inline long find_zero(unsigned long mask)		static inline long find_zero(unsigned long mask)
	{		{
	long byte = 0;		long byte = 0;

			#ifdef __BIG_ENDIAN
	#ifdef CONFIG_64BIT		#ifdef CONFIG_64BIT
	if (mask >> 32)		if (mask >> 32)
	mask >>= 32;		mask >>= 32;
	@@ -25,7 +29,27 @@ static inline long find_zero(unsigned long mask)
	else		else
	byte += 2;		byte += 2;
	return (mask >> 8) ? byte : byte + 1;		return (mask >> 8) ? byte : byte + 1;
			#else
			#ifdef CONFIG_64BIT
			if (!((unsigned int) mask)) {
			mask >>= 32;
			byte = 4;
	}		}
			#endif
			if (!(mask & 0xffff)) {
			mask >>= 16;
			byte += 2;
			}
			return (mask & 0xff) ? byte : byte + 1;
			#endif
			}

			#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
			#define IS_UNALIGNED(src, dst) 0
			#else
			#define IS_UNALIGNED(src, dst) \
			(((long) dst \| (long) src) & (sizeof(long) - 1))
			#endif

	/*		/*
	* Do a strncpy, return length of string without final '\0'.		* Do a strncpy, return length of string without final '\0'.
	@@ -46,7 +70,7 @@ static inline long do_strncpy_from_user(char dst, const char __user src, long
	if (max > count)		if (max > count)
	max = count;		max = count;

	if (((long) dst \| (long) src) & (sizeof(long) - 1))		if (IS_UNALIGNED(src, dst))
	goto byte_at_a_time;		goto byte_at_a_time;

	while (max >= sizeof(unsigned long)) {		while (max >= sizeof(unsigned long)) {
	@@ -59,7 +83,7 @@ static inline long do_strncpy_from_user(char dst, const char __user src, long
	v = (c + high_bits) & ~rhs;		v = (c + high_bits) & ~rhs;
	(unsigned long )(dst+res) = c;		(unsigned long )(dst+res) = c;
	if (v) {		if (v) {
	v = (c & low_bits) + low_bits;;		v = (c & low_bits) + low_bits;
	v = ~(v \| rhs);		v = ~(v \| rhs);
	return res + find_zero(v);		return res + find_zero(v);
	}		}
	@@ -119,9 +143,7 @@ long strncpy_from_user(char dst, const char __user src, long count)
	if (unlikely(count <= 0))		if (unlikely(count <= 0))
	return 0;		return 0;

	max_addr = ~0UL;		max_addr = user_addr_max();
	if (likely(segment_eq(get_fs(), USER_DS)))
	max_addr = STACK_TOP;
	src_addr = (unsigned long)src;		src_addr = (unsigned long)src;
	if (likely(src_addr < max_addr)) {		if (likely(src_addr < max_addr)) {
	unsigned long max = max_addr - src_addr;		unsigned long max = max_addr - src_addr;

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