[PATCH 5.10 097/199] iov_iter: fix the uaccess area in copy_compat_iovec_from_user

Greg Kroah-Hartman
2021-01-26T09:50:51Z

From: Christoph Hellwig <hch@lst.de>

[ Upstream commit a959a9782fa87669feeed095ced5d78181a7c02d ]

sizeof needs to be called on the compat pointer, not the native one.

Fixes: 89cd35c58bc2 ("iov_iter: transparently handle compat iovecs in import_iovec")
Reported-by: David Laight <David.Laight@ACULAB.COM>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
lib/iov_iter.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 1635111c5bd2a..a21e6a5792c5a 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1658,7 +1658,7 @@ static int copy_compat_iovec_from_user(struct iovec *iov,
(const struct compat_iovec __user *)uvec;
int ret = -EFAULT, i;

- if (!user_access_begin(uvec, nr_segs * sizeof(*uvec)))
+ if (!user_access_begin(uiov, nr_segs * sizeof(*uiov)))
return -EFAULT;

for (i = 0; i < nr_segs; i++) {
--
2.27.0