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 <jens.axboe@oracle.com>
Cc: Wojciech Purczynski <cliph@research.coseinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/splice.c b/fs/splice.c
index 4ee49e8..14e2262 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1179,6 +1179,9 @@
{
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 @@
break;
}
+ if (unlikely(!access_ok(VERIFY_WRITE, base, len))) {
+ error = -EFAULT;
+ break;
+ }
+
sd.len = 0;
sd.total_len = len;
sd.flags = flags;