diff options
Diffstat (limited to 'mm/usercopy.c')
| -rw-r--r-- | mm/usercopy.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/mm/usercopy.c b/mm/usercopy.c index a562dd094ace..e9e9325f7638 100644 --- a/mm/usercopy.c +++ b/mm/usercopy.c @@ -59,13 +59,28 @@ static noinline int check_stack_object(const void *obj, unsigned long len) } /* - * If this function is reached, then CONFIG_HARDENED_USERCOPY has found an - * unexpected state during a copy_from_user() or copy_to_user() call. + * If these functions are reached, then CONFIG_HARDENED_USERCOPY has found + * an unexpected state during a copy_from_user() or copy_to_user() call. * There are several checks being performed on the buffer by the * __check_object_size() function. Normal stack buffer usage should never * trip the checks, and kernel text addressing will always trip the check. - * For cache objects, copies must be within the object size. + * For cache objects, it is checking that only the whitelisted range of + * bytes for a given cache is being accessed (via the cache's usersize and + * useroffset fields). To adjust a cache whitelist, use the usercopy-aware + * kmem_cache_create_usercopy() function to create the cache (and + * carefully audit the whitelist range). */ +void usercopy_warn(const char *name, const char *detail, bool to_user, + unsigned long offset, unsigned long len) +{ + WARN_ONCE(1, "Bad or missing usercopy whitelist? Kernel memory %s attempt detected %s %s%s%s%s (offset %lu, size %lu)!\n", + to_user ? "exposure" : "overwrite", + to_user ? "from" : "to", + name ? : "unknown?!", + detail ? " '" : "", detail ? : "", detail ? "'" : "", + offset, len); +} + void __noreturn usercopy_abort(const char *name, const char *detail, bool to_user, unsigned long offset, unsigned long len) |