Check before entering into cycle and on every iteration.
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 | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index b44bdb2..5f4be69 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -57,6 +57,9 @@ static int nilfs_ioctl_wrap_copy(struct the_nilfs *nilfs,
if (argv->v_size > PAGE_SIZE)
return -EINVAL;
+ if (argv->v_index > ULONG_MAX - argv->v_nmembs)
+ return -EINVAL;
+
buf = (void *)__get_free_pages(GFP_NOFS, 0);
if (unlikely(!buf))
return -ENOMEM;
@@ -90,8 +93,13 @@ static int nilfs_ioctl_wrap_copy(struct the_nilfs *nilfs,
total += nr;
if ((size_t)nr < n)
break;
- if (pos == ppos)
+ if (pos == ppos) {
+ if (pos > ULONG_MAX - n) {
+ ret = -EINVAL;
+ break;
+ }
pos += n;
+ }
}
argv->v_nmembs = total;
--
1.8.5.rc1.28.g7061504
--
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