linux-kernel - [PATCH] iov_iter: Use user_read_access_begin() instead of user_access

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Message-Id: <25459896a398909d195fd5eb3d82ca1acb07b783.1615381467.git.christophe.leroy@csgroup.eu>
Date:   Wed, 10 Mar 2021 13:08:31 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Alexander Viro <viro@...iv.linux.org.uk>
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH] iov_iter: Use user_read_access_begin() instead of
 user_access_begin()

copy_compat_iovec_from_user() only do unsafe_get_user(),
it only requires read access.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 lib/iov_iter.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index f66c62aa7154..76952a117b47 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1665,7 +1665,7 @@ static int copy_compat_iovec_from_user(struct iovec *iov,
 		(const struct compat_iovec __user *)uvec;
 	int ret = -EFAULT, i;
 
-	if (!user_access_begin(uiov, nr_segs * sizeof(*uiov)))
+	if (!user_read_access_begin(uiov, nr_segs * sizeof(*uiov)))
 		return -EFAULT;
 
 	for (i = 0; i < nr_segs; i++) {
@@ -1686,7 +1686,7 @@ static int copy_compat_iovec_from_user(struct iovec *iov,
 
 	ret = 0;
 uaccess_end:
-	user_access_end();
+	user_read_access_end();
 	return ret;
 }
 
-- 
2.25.0