splice: missing user pointer access verification

vmsplice_to_user() must always check the user pointer and length with access_ok() before copying. Likewise, for the slow path of copy_from_user_mmap_sem() we need to check that we may read from the user region. Signed-off-by: Jens Axboe <[email protected]> Cc: Wojciech Purczynski <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
chewitt · Feb 8, 2008 · 8811930 · 8811930
1 parent 66191dc
commit 8811930
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/fs/splice.c b/fs/splice.c
@@ -1179,6 +1179,9 @@ static int copy_from_user_mmap_sem(void *dst, const void __user *src, size_t n)
 {
 	int partial;
 
+	if (!access_ok(VERIFY_READ, src, n))
+		return -EFAULT;
+
 	pagefault_disable();
 	partial = __copy_from_user_inatomic(dst, src, n);
 	pagefault_enable();
@@ -1387,6 +1390,11 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *iov,
 			break;
 		}
 
+		if (unlikely(!access_ok(VERIFY_WRITE, base, len))) {
+			error = -EFAULT;
+			break;
+		}
+
 		sd.len = 0;
 		sd.total_len = len;
 		sd.flags = flags;