Commit 36903abe authored by Arnd Bergmann's avatar Arnd Bergmann
Browse files

x86: remove __range_not_ok() 



The __range_not_ok() helper is an x86 (and sparc64) specific interface
that does roughly the same thing as __access_ok(), but with different
calling conventions.

Change this to use the normal interface in order for consistency as we
clean up all access_ok() implementations.

This changes the limit from TASK_SIZE to TASK_SIZE_MAX, which Al points
out is the right thing do do here anyway.

The callers have to use __access_ok() instead of the normal access_ok()
though, because on x86 that contains a WARN_ON_IN_IRQ() check that cannot
be used inside of NMI context while tracing.

The check in copy_code() is not needed any more, because this one is
already done by copy_from_user_nmi().

Suggested-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Suggested-by: default avatarChristoph Hellwig <hch@infradead.org>
Link: https://lore.kernel.org/lkml/YgsUKcXGR7r4nINj@zeniv-ca.linux.org.uk/


Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
parent 8afafbc9

arch/x86/events/core.c

+1 −1
Original line number Diff line number Diff line
@@ -2794,7 +2794,7 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re 
static inline int

valid_user_frame(const void __user *fp, unsigned long size)

{

	return (__range_not_ok(fp, size, TASK_SIZE) == 0);

	return __access_ok(fp, size);

}



static unsigned long get_segment_base(unsigned int segment)

arch/x86/include/asm/uaccess.h

+6 −4
Original line number Diff line number Diff line
@@ -16,8 +16,10 @@ 
 * Test whether a block of memory is a valid user space address.

 * Returns 0 if the range is valid, nonzero otherwise.

 */

static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, unsigned long limit)

static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size)

{

	unsigned long limit = TASK_SIZE_MAX;



	/*

	 * If we have used "sizeof()" for the size,

	 * we know it won't overflow the limit (but
@@ -35,10 +37,10 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un 
	return unlikely(addr > limit);

}



#define __range_not_ok(addr, size, limit)				\

#define __access_ok(addr, size)						\

({									\

	__chk_user_ptr(addr);						\

	__chk_range_not_ok((unsigned long __force)(addr), size, limit); \

	!__chk_range_not_ok((unsigned long __force)(addr), size);	\

})



#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
@@ -69,7 +71,7 @@ static inline bool pagefault_disabled(void); 
#define access_ok(addr, size)					\

({									\

	WARN_ON_IN_IRQ();						\

	likely(!__range_not_ok(addr, size, TASK_SIZE_MAX));		\

	likely(__access_ok(addr, size));				\

})



extern int __get_user_1(void);

arch/x86/kernel/dumpstack.c

+0 −6
Original line number Diff line number Diff line
@@ -81,12 +81,6 @@ static int copy_code(struct pt_regs *regs, u8 *buf, unsigned long src, 
	/* The user space code from other tasks cannot be accessed. */

	if (regs != task_pt_regs(current))

		return -EPERM;

	/*

	 * Make sure userspace isn't trying to trick us into dumping kernel

	 * memory by pointing the userspace instruction pointer at it.

	 */

	if (__chk_range_not_ok(src, nbytes, TASK_SIZE_MAX))

		return -EINVAL;



	/*

	 * Even if named copy_from_user_nmi() this can be invoked from

arch/x86/kernel/stacktrace.c

+1 −1
Original line number Diff line number Diff line
@@ -90,7 +90,7 @@ copy_stack_frame(const struct stack_frame_user __user *fp, 
{

	int ret;



	if (__range_not_ok(fp, sizeof(*frame), TASK_SIZE))

	if (!__access_ok(fp, sizeof(*frame)))

		return 0;



	ret = 1;

arch/x86/lib/usercopy.c

+1 −1
Original line number Diff line number Diff line
@@ -32,7 +32,7 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n) 
{

	unsigned long ret;



	if (__range_not_ok(from, n, TASK_SIZE))

	if (!__access_ok(from, n))

		return n;



	if (!nmi_uaccess_okay())