[PATCH AUTOSEL 4.19 20/47] ceph: return -ERANGE if virtual xattr value didn't fit in buffer

Sasha Levin
2019-07-26T13:55:42Z

From: Jeff Layton <jlayton@kernel.org>

[ Upstream commit 3b421018f48c482bdc9650f894aa1747cf90e51d ]

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>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Acked-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@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 996ee87b1eaf..7e6d3df99f2f 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -79,7 +79,7 @@ static size_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);

@@ -103,11 +103,8 @@ static size_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) {
@@ -817,8 +814,11 @@ 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;
}

--
2.20.1