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x86: remove __range_not_ok()

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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: Al Viro <viro@zeniv.linux.org.uk>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Link: https://lore.kernel.org/lkml/YgsUKcXGR7r4nINj@zeniv-ca.linux.org.uk/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Arnd Bergmann 2022-02-15 09:15:57 +01:00
parent 8afafbc955
commit 36903abedf
5 changed files with 9 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/events/core.c
View File

@ -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)

10
arch/x86/include/asm/uaccess.h
View File

@ -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);

6
arch/x86/kernel/dumpstack.c
View File

@ -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

2
arch/x86/kernel/stacktrace.c
View File

@ -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;

2
arch/x86/lib/usercopy.c
View File

@ -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())