diff options
| -rw-r--r-- | kernel/perf_counter.c | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index d5899b62b276..cc768ab81ac8 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -4208,8 +4208,8 @@ done: static int perf_copy_attr(struct perf_counter_attr __user *uattr, struct perf_counter_attr *attr) { - int ret; u32 size; + int ret; if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0)) return -EFAULT; @@ -4234,19 +4234,19 @@ static int perf_copy_attr(struct perf_counter_attr __user *uattr, /* * If we're handed a bigger struct than we know of, - * ensure all the unknown bits are 0. + * ensure all the unknown bits are 0 - i.e. new + * user-space does not rely on any kernel feature + * extensions we dont know about yet. */ if (size > sizeof(*attr)) { - unsigned long val; - unsigned long __user *addr; - unsigned long __user *end; + unsigned char __user *addr; + unsigned char __user *end; + unsigned char val; - addr = PTR_ALIGN((void __user *)uattr + sizeof(*attr), - sizeof(unsigned long)); - end = PTR_ALIGN((void __user *)uattr + size, - sizeof(unsigned long)); + addr = (void __user *)uattr + sizeof(*attr); + end = (void __user *)uattr + size; - for (; addr < end; addr += sizeof(unsigned long)) { + for (; addr < end; addr++) { ret = get_user(val, addr); if (ret) return ret; |