diff options
Diffstat (limited to 'arch/arm64/include/asm/uaccess.h')
| -rw-r--r-- | arch/arm64/include/asm/uaccess.h | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index c47257c91b77..55d0adbf6509 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -21,6 +21,7 @@ /* * User space memory access functions */ +#include <linux/bitops.h> #include <linux/kasan-checks.h> #include <linux/string.h> #include <linux/thread_info.h> @@ -102,6 +103,13 @@ static inline void set_fs(mm_segment_t fs) flag; \ }) +/* + * When dealing with data aborts or instruction traps we may end up with + * a tagged userland pointer. Clear the tag to get a sane pointer to pass + * on to access_ok(), for instance. + */ +#define untagged_addr(addr) sign_extend64(addr, 55) + #define access_ok(type, addr, size) __range_ok(addr, size) #define user_addr_max get_fs @@ -278,14 +286,16 @@ static inline unsigned long __must_check __copy_to_user(void __user *to, const v static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n) { + unsigned long res = n; kasan_check_write(to, n); if (access_ok(VERIFY_READ, from, n)) { check_object_size(to, n, false); - n = __arch_copy_from_user(to, from, n); - } else /* security hole - plug it */ - memset(to, 0, n); - return n; + res = __arch_copy_from_user(to, from, n); + } + if (unlikely(res)) + memset(to + (n - res), 0, res); + return res; } static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n) |