diff options
Diffstat (limited to 'lib/strnlen_user.c')
| -rw-r--r-- | lib/strnlen_user.c | 25 |
1 files changed, 10 insertions, 15 deletions
diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c index 7f2db3fe311f..41670d4a5816 100644 --- a/lib/strnlen_user.c +++ b/lib/strnlen_user.c @@ -2,16 +2,11 @@ #include <linux/kernel.h> #include <linux/export.h> #include <linux/uaccess.h> +#include <linux/mm.h> +#include <linux/bitops.h> #include <asm/word-at-a-time.h> -/* Set bits in the first 'n' bytes when loaded from memory */ -#ifdef __LITTLE_ENDIAN -# define aligned_byte_mask(n) ((1ul << 8*(n))-1) -#else -# define aligned_byte_mask(n) (~0xfful << (BITS_PER_LONG - 8 - 8*(n))) -#endif - /* * Do a strnlen, return length of string *with* final '\0'. * 'count' is the user-supplied count, while 'max' is the @@ -32,13 +27,6 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count, unsigned long c; /* - * Truncate 'max' to the user-specified limit, so that - * we only have one limit we need to check in the loop - */ - if (max > count) - max = count; - - /* * Do everything aligned. But that means that we * need to also expand the maximum.. */ @@ -109,11 +97,18 @@ long strnlen_user(const char __user *str, long count) return 0; max_addr = user_addr_max(); - src_addr = (unsigned long)str; + src_addr = (unsigned long)untagged_addr(str); if (likely(src_addr < max_addr)) { unsigned long max = max_addr - src_addr; long retval; + /* + * Truncate 'max' to the user-specified limit, so that + * we only have one limit we need to check in the loop + */ + if (max > count) + max = count; + if (user_access_begin(str, max)) { retval = do_strnlen_user(str, count, max); user_access_end(); |
