diff options
Diffstat (limited to 'mm/usercopy.c')
| -rw-r--r-- | mm/usercopy.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/mm/usercopy.c b/mm/usercopy.c index d0d268135d96..5d34c40c16c2 100644 --- a/mm/usercopy.c +++ b/mm/usercopy.c @@ -29,7 +29,7 @@ * Returns: * NOT_STACK: not at all on the stack * GOOD_FRAME: fully within a valid stack frame - * GOOD_STACK: fully on the stack (when can't do frame-checking) + * GOOD_STACK: within the current stack (when can't frame-check exactly) * BAD_STACK: error condition (invalid stack position or bad stack frame) */ static noinline int check_stack_object(const void *obj, unsigned long len) @@ -55,6 +55,17 @@ static noinline int check_stack_object(const void *obj, unsigned long len) if (ret) return ret; + /* Finally, check stack depth if possible. */ +#ifdef CONFIG_ARCH_HAS_CURRENT_STACK_POINTER + if (IS_ENABLED(CONFIG_STACK_GROWSUP)) { + if ((void *)current_stack_pointer < obj + len) + return BAD_STACK; + } else { + if (obj < (void *)current_stack_pointer) + return BAD_STACK; + } +#endif + return GOOD_STACK; } @@ -280,7 +291,15 @@ void __check_object_size(const void *ptr, unsigned long n, bool to_user) */ return; default: - usercopy_abort("process stack", NULL, to_user, 0, n); + usercopy_abort("process stack", NULL, to_user, +#ifdef CONFIG_ARCH_HAS_CURRENT_STACK_POINTER + IS_ENABLED(CONFIG_STACK_GROWSUP) ? + ptr - (void *)current_stack_pointer : + (void *)current_stack_pointer - ptr, +#else + 0, +#endif + n); } /* Check for bad heap object. */ |