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maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault

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Better describe what these functions do.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Christoph Hellwig
2020-06-17 09:37:53 +02:00
committed by Linus Torvalds
parent b3a9e3b962
commit fe557319aa
50 changed files with 138 additions and 122 deletions
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49
mm/maccess.c
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@@ -6,14 +6,15 @@
#include <linux/mm.h>
#include <linux/uaccess.h>
bool __weak probe_kernel_read_allowed(const void *unsafe_src, size_t size)
bool __weak copy_from_kernel_nofault_allowed(const void *unsafe_src,
size_t size)
{
return true;
}
#ifdef HAVE_GET_KERNEL_NOFAULT
#define probe_kernel_read_loop(dst, src, len, type, err_label) \
#define copy_from_kernel_nofault_loop(dst, src, len, type, err_label) \
while (len >= sizeof(type)) { \
__get_kernel_nofault(dst, src, type, err_label); \
dst += sizeof(type); \
@@ -21,25 +22,25 @@ bool __weak probe_kernel_read_allowed(const void *unsafe_src, size_t size)
len -= sizeof(type); \
}
long probe_kernel_read(void *dst, const void *src, size_t size)
long copy_from_kernel_nofault(void *dst, const void *src, size_t size)
{
if (!probe_kernel_read_allowed(src, size))
if (!copy_from_kernel_nofault_allowed(src, size))
return -ERANGE;
pagefault_disable();
probe_kernel_read_loop(dst, src, size, u64, Efault);
probe_kernel_read_loop(dst, src, size, u32, Efault);
probe_kernel_read_loop(dst, src, size, u16, Efault);
probe_kernel_read_loop(dst, src, size, u8, Efault);
copy_from_kernel_nofault_loop(dst, src, size, u64, Efault);
copy_from_kernel_nofault_loop(dst, src, size, u32, Efault);
copy_from_kernel_nofault_loop(dst, src, size, u16, Efault);
copy_from_kernel_nofault_loop(dst, src, size, u8, Efault);
pagefault_enable();
return 0;
Efault:
pagefault_enable();
return -EFAULT;
}
EXPORT_SYMBOL_GPL(probe_kernel_read);
EXPORT_SYMBOL_GPL(copy_from_kernel_nofault);
#define probe_kernel_write_loop(dst, src, len, type, err_label) \
#define copy_to_kernel_nofault_loop(dst, src, len, type, err_label) \
while (len >= sizeof(type)) { \
__put_kernel_nofault(dst, src, type, err_label); \
dst += sizeof(type); \
@@ -47,13 +48,13 @@ EXPORT_SYMBOL_GPL(probe_kernel_read);
len -= sizeof(type); \
}
long probe_kernel_write(void *dst, const void *src, size_t size)
long copy_to_kernel_nofault(void *dst, const void *src, size_t size)
{
pagefault_disable();
probe_kernel_write_loop(dst, src, size, u64, Efault);
probe_kernel_write_loop(dst, src, size, u32, Efault);
probe_kernel_write_loop(dst, src, size, u16, Efault);
probe_kernel_write_loop(dst, src, size, u8, Efault);
copy_to_kernel_nofault_loop(dst, src, size, u64, Efault);
copy_to_kernel_nofault_loop(dst, src, size, u32, Efault);
copy_to_kernel_nofault_loop(dst, src, size, u16, Efault);
copy_to_kernel_nofault_loop(dst, src, size, u8, Efault);
pagefault_enable();
return 0;
Efault:
@@ -67,7 +68,7 @@ long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count)
if (unlikely(count <= 0))
return 0;
if (!probe_kernel_read_allowed(unsafe_addr, count))
if (!copy_from_kernel_nofault_allowed(unsafe_addr, count))
return -ERANGE;
pagefault_disable();
@@ -87,7 +88,7 @@ Efault:
}
#else /* HAVE_GET_KERNEL_NOFAULT */
/**
* probe_kernel_read(): safely attempt to read from kernel-space
* copy_from_kernel_nofault(): safely attempt to read from kernel-space
* @dst: pointer to the buffer that shall take the data
* @src: address to read from
* @size: size of the data chunk
@@ -98,15 +99,15 @@ Efault:
*
* We ensure that the copy_from_user is executed in atomic context so that
* do_page_fault() doesn't attempt to take mmap_lock. This makes
* probe_kernel_read() suitable for use within regions where the caller
* copy_from_kernel_nofault() suitable for use within regions where the caller
* already holds mmap_lock, or other locks which nest inside mmap_lock.
*/
long probe_kernel_read(void *dst, const void *src, size_t size)
long copy_from_kernel_nofault(void *dst, const void *src, size_t size)
{
long ret;
mm_segment_t old_fs = get_fs();
if (!probe_kernel_read_allowed(src, size))
if (!copy_from_kernel_nofault_allowed(src, size))
return -ERANGE;
set_fs(KERNEL_DS);
@@ -120,10 +121,10 @@ long probe_kernel_read(void *dst, const void *src, size_t size)
return -EFAULT;
return 0;
}
EXPORT_SYMBOL_GPL(probe_kernel_read);
EXPORT_SYMBOL_GPL(copy_from_kernel_nofault);
/**
* probe_kernel_write(): safely attempt to write to a location
* copy_to_kernel_nofault(): safely attempt to write to a location
* @dst: address to write to
* @src: pointer to the data that shall be written
* @size: size of the data chunk
@@ -131,7 +132,7 @@ EXPORT_SYMBOL_GPL(probe_kernel_read);
* Safely write to address @dst from the buffer at @src. If a kernel fault
* happens, handle that and return -EFAULT.
*/
long probe_kernel_write(void *dst, const void *src, size_t size)
long copy_to_kernel_nofault(void *dst, const void *src, size_t size)
{
long ret;
mm_segment_t old_fs = get_fs();
@@ -174,7 +175,7 @@ long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count)
if (unlikely(count <= 0))
return 0;
if (!probe_kernel_read_allowed(unsafe_addr, count))
if (!copy_from_kernel_nofault_allowed(unsafe_addr, count))
return -ERANGE;
set_fs(KERNEL_DS);