author: Christoph Hellwig <hch@lst.de> 2020-08-11 18:33:47 -0700
committer: Linus Torvalds <torvalds@linux-foundation.org> 2020-08-12 10:57:59 -0700
commit: 3d13f313ce4c34c524ccc37986fe77172f601ff3
parent: 428e2976a5bf7e7f5554286d7a5a33b8147b106a
Commit Summary:
Diffstat:
1 file changed, 10 insertions, 12 deletions
diff --git a/mm/maccess.c b/mm/maccess.c
index f98ff91e32c6..3bd70405f2d8 100644
--- a/mm/maccess.c
+++ b/mm/maccess.c
@@ -205,15 +205,14 @@ long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count)
long copy_from_user_nofault(void *dst, const void __user *src, size_t size)
{
long ret = -EFAULT;
- mm_segment_t old_fs = get_fs();
+ mm_segment_t old_fs = force_uaccess_begin();
- set_fs(USER_DS);
if (access_ok(src, size)) {
pagefault_disable();
ret = __copy_from_user_inatomic(dst, src, size);
pagefault_enable();
}
- set_fs(old_fs);
+ force_uaccess_end(old_fs);
if (ret)
return -EFAULT;
@@ -233,15 +232,14 @@ EXPORT_SYMBOL_GPL(copy_from_user_nofault);
long copy_to_user_nofault(void __user *dst, const void *src, size_t size)
{
long ret = -EFAULT;
- mm_segment_t old_fs = get_fs();
+ mm_segment_t old_fs = force_uaccess_begin();
- set_fs(USER_DS);
if (access_ok(dst, size)) {
pagefault_disable();
ret = __copy_to_user_inatomic(dst, src, size);
pagefault_enable();
}
- set_fs(old_fs);
+ force_uaccess_end(old_fs);
if (ret)
return -EFAULT;
@@ -270,17 +268,17 @@ EXPORT_SYMBOL_GPL(copy_to_user_nofault);
long strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr,
long count)
{
- mm_segment_t old_fs = get_fs();
+ mm_segment_t old_fs;
long ret;
if (unlikely(count <= 0))
return 0;
- set_fs(USER_DS);
+ old_fs = force_uaccess_begin();
pagefault_disable();
ret = strncpy_from_user(dst, unsafe_addr, count);
pagefault_enable();
- set_fs(old_fs);
+ force_uaccess_end(old_fs);
if (ret >= count) {
ret = count;
@@ -310,14 +308,14 @@ long strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr,
*/
long strnlen_user_nofault(const void __user *unsafe_addr, long count)
{
- mm_segment_t old_fs = get_fs();
+ mm_segment_t old_fs;
int ret;
- set_fs(USER_DS);
+ old_fs = force_uaccess_begin();
pagefault_disable();
ret = strnlen_user(unsafe_addr, count);
pagefault_enable();
- set_fs(old_fs);
+ force_uaccess_end(old_fs);
return ret;
}