[PATCH] fs/nilfs2: Integer overflow in nilfs_ioctl_wrap_copy()

[Wenliang Fan]

The local variable 'pos' comes from userspace. If a large number was
passed, there would be an integer overflow in the following line:
        pos += n;

Signed-off-by: Wenliang Fan <fanwlexca@xxxxxxxxx>
---
 fs/nilfs2/ioctl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index b44bdb2..a260a98 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -65,6 +65,8 @@ static int nilfs_ioctl_wrap_copy(struct the_nilfs *nilfs,
 	ret = 0;
 	total = 0;
 	pos = argv->v_index;
+	if (pos > ULONG_MAX - argv->v_nmembs)
+		return -EINVAL;
 	for (i = 0; i < argv->v_nmembs; i += n) {
 		n = (argv->v_nmembs - i < maxmembs) ?
 			argv->v_nmembs - i : maxmembs;
-- 
1.8.5.rc1.28.g7061504

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