diff options
Diffstat (limited to 'mm/util.c')
| -rw-r--r-- | mm/util.c | 32 |
1 files changed, 24 insertions, 8 deletions
diff --git a/mm/util.c b/mm/util.c index 834db7be240f..4735ea481816 100644 --- a/mm/util.c +++ b/mm/util.c @@ -186,6 +186,27 @@ void kzfree(const void *p) } EXPORT_SYMBOL(kzfree); +int kern_ptr_validate(const void *ptr, unsigned long size) +{ + unsigned long addr = (unsigned long)ptr; + unsigned long min_addr = PAGE_OFFSET; + unsigned long align_mask = sizeof(void *) - 1; + + if (unlikely(addr < min_addr)) + goto out; + if (unlikely(addr > (unsigned long)high_memory - size)) + goto out; + if (unlikely(addr & align_mask)) + goto out; + if (unlikely(!kern_addr_valid(addr))) + goto out; + if (unlikely(!kern_addr_valid(addr + size - 1))) + goto out; + return 1; +out: + return 0; +} + /* * strndup_user - duplicate an existing string from user space * @s: The string to duplicate @@ -204,15 +225,10 @@ char *strndup_user(const char __user *s, long n) if (length > n) return ERR_PTR(-EINVAL); - p = kmalloc(length, GFP_KERNEL); + p = memdup_user(s, length); - if (!p) - return ERR_PTR(-ENOMEM); - - if (copy_from_user(p, s, length)) { - kfree(p); - return ERR_PTR(-EFAULT); - } + if (IS_ERR(p)) + return p; p[length - 1] = '\0'; |