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From:   Jeff Layton <jlayton@kernel.org>
To:     linux-kernel@vger.kernel.org, ceph-devel@vger.kernel.org
Cc:     idryomov@gmail.com, zyan@redhat.com, sage@redhat.com,
        agruenba@redhat.com
Subject: [PATCH v4 2/3] ceph: return -ERANGE if virtual xattr value didn't fit in buffer
Date:   Mon, 24 Jun 2019 12:27:25 -0400
Message-Id: <20190624162726.17413-3-jlayton@kernel.org>
In-Reply-To: <20190624162726.17413-1-jlayton@kernel.org>
References: <20190624162726.17413-1-jlayton@kernel.org>
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The getxattr manpage states that we should return ERANGE if the
destination buffer size is too small to hold the value.
ceph_vxattrcb_layout does this internally, but we should be doing
this for all vxattrs.

Fix the only caller of getxattr_cb to check the returned size
against the buffer length and return -ERANGE if it doesn't fit.
Drop the same check in ceph_vxattrcb_layout and just rely on the
caller to handle it.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/ceph/xattr.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index e90e19e9660b..9b77dca0b786 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -63,7 +63,7 @@ static ssize_t ceph_vxattrcb_layout(struct ceph_inode_info *ci, char *val,
 	const char *ns_field = " pool_namespace=";
 	char buf[128];
 	size_t len, total_len = 0;
-	int ret;
+	ssize_t ret;
 
 	pool_ns = ceph_try_get_string(ci->i_layout.pool_ns);
 
@@ -87,11 +87,8 @@ static ssize_t ceph_vxattrcb_layout(struct ceph_inode_info *ci, char *val,
 	if (pool_ns)
 		total_len += strlen(ns_field) + pool_ns->len;
 
-	if (!size) {
-		ret = total_len;
-	} else if (total_len > size) {
-		ret = -ERANGE;
-	} else {
+	ret = total_len;
+	if (size >= total_len) {
 		memcpy(val, buf, len);
 		ret = len;
 		if (pool_name) {
@@ -803,8 +800,11 @@ ssize_t __ceph_getxattr(struct inode *inode, const char *name, void *value,
 		if (err)
 			return err;
 		err = -ENODATA;
-		if (!(vxattr->exists_cb && !vxattr->exists_cb(ci)))
+		if (!(vxattr->exists_cb && !vxattr->exists_cb(ci))) {
 			err = vxattr->getxattr_cb(ci, value, size);
+			if (size && size < err)
+				err = -ERANGE;
+		}
 		return err;
 	}
 
-- 
2.21.0