Messages in this thread Patch in this message | | | From | Mike Frysinger <> | Subject | [PATCH] asm-generic: uaccess: fix up local access_ok() usage | Date | Sat, 13 Jun 2009 10:30:46 -0400 |
| |
There's no reason that I can see to use the short __access_ok() form directly when the access_ok() is clearer in intent and for more people, expands to the same C code (i.e. always specify the first field -- access type). Not all no-mmu systems lack memory protection, so the read/write could feasibly be checked.
Also, the strnlen_user() function was missing a access_ok() check on the pointer given. We've had cases on Blackfin systems where test cases caused kernel crashes here because userspace passed up a NULL/-1 pointer and the kernel gladly attempted to run strlen() on it.
Signed-off-by: Mike Frysinger <vapier@gentoo.org> --- include/asm-generic/uaccess.h | 14 ++++++++------ 1 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h index 6d8cab2..705410b 100644 --- a/include/asm-generic/uaccess.h +++ b/include/asm-generic/uaccess.h @@ -163,7 +163,7 @@ static inline __must_check long __copy_to_user(void __user *to, #define put_user(x, ptr) \ ({ \ might_sleep(); \ - __access_ok(ptr, sizeof (*ptr)) ? \ + access_ok(VERIFY_WRITE, ptr, sizeof (*ptr)) ? \ __put_user(x, ptr) : \ -EFAULT; \ }) @@ -219,7 +219,7 @@ extern int __put_user_bad(void) __attribute__((noreturn)); #define get_user(x, ptr) \ ({ \ might_sleep(); \ - __access_ok(ptr, sizeof (*ptr)) ? \ + access_ok(VERIFY_READ, ptr, sizeof (*ptr)) ? \ __get_user(x, ptr) : \ -EFAULT; \ }) @@ -244,7 +244,7 @@ static inline long copy_from_user(void *to, const void __user * from, unsigned long n) { might_sleep(); - if (__access_ok(from, n)) + if (access_ok(VERIFY_READ, from, n)) return __copy_from_user(to, from, n); else return n; @@ -254,7 +254,7 @@ static inline long copy_to_user(void __user *to, const void *from, unsigned long n) { might_sleep(); - if (__access_ok(to, n)) + if (access_ok(VERIFY_WRITE, to, n)) return __copy_to_user(to, from, n); else return n; @@ -278,7 +278,7 @@ __strncpy_from_user(char *dst, const char __user *src, long count) static inline long strncpy_from_user(char *dst, const char __user *src, long count) { - if (!__access_ok(src, 1)) + if (!access_ok(VERIFY_READ, src, 1)) return -EFAULT; return __strncpy_from_user(dst, src, count); } @@ -291,6 +291,8 @@ strncpy_from_user(char *dst, const char __user *src, long count) #ifndef strnlen_user static inline long strnlen_user(const char __user *src, long n) { + if (!access_ok(VERIFY_READ, src, 1)) + return 0; return strlen((void * __force)src) + 1; } #endif @@ -316,7 +318,7 @@ static inline __must_check unsigned long clear_user(void __user *to, unsigned long n) { might_sleep(); - if (!__access_ok(to, n)) + if (!access_ok(VERIFY_WRITE, to, n)) return n; return __clear_user(to, n); -- 1.6.3.1
| |