Do not map STATUS_OBJECT_NAME_INVALID to -EREMOTE under non-DFS
shares, or 'nodfs' mounts or CONFIG_CIFS_DFS_UPCALL=n builds.
Otherwise, in the slow path, get a referral to figure out whether it
is an actual DFS link.
This could be simply reproduced under a non-DFS share by running the
following
$ mount.cifs //srv/share /mnt -o ...
$ cat /mnt/$(printf '\U110000')
cat: '/mnt/'$'\364\220\200\200': Object is remote
Fixes: c877ce47e137 ("cifs: reduce roundtrips on create/qinfo requests")
Signed-off-by: Paulo Alcantara (SUSE) <pc@xxxxxxxxxxxxx>
---
fs/cifs/cifsproto.h | 20 ++++++++++----
fs/cifs/misc.c | 66 +++++++++++++++++++++++++++++++++++++++++++++
fs/cifs/smb2inode.c | 21 ++++++++-------
fs/cifs/smb2ops.c | 23 +++++++++-------
4 files changed, 105 insertions(+), 25 deletions(-)
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index b7a36ebd0f2f..20a2f0f3f682 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -667,11 +667,21 @@ static inline int get_dfs_path(const unsigned int xid, struct cifs_ses *ses,
int match_target_ip(struct TCP_Server_Info *server,
const char *share, size_t share_len,
bool *result);
-
-int cifs_dfs_query_info_nonascii_quirk(const unsigned int xid,
- struct cifs_tcon *tcon,
- struct cifs_sb_info *cifs_sb,
- const char *dfs_link_path);
+int cifs_inval_name_dfs_link_error(const unsigned int xid,
+ struct cifs_tcon *tcon,
+ struct cifs_sb_info *cifs_sb,
+ const char *full_path,
+ bool *islink);
+#else
+static inline int cifs_inval_name_dfs_link_error(const unsigned int xid,
+ struct cifs_tcon *tcon,
+ struct cifs_sb_info *cifs_sb,
+ const char *full_path,
+ bool *islink)
+{
+ *islink = false;
+ return 0;
+}
#endif
static inline int cifs_create_options(struct cifs_sb_info *cifs_sb, int options)
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 2905734eb289..003b0a522fea 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -21,6 +21,7 @@
#include "cifsfs.h"
#ifdef CONFIG_CIFS_DFS_UPCALL
#include "dns_resolve.h"
+#include "dfs_cache.h"
#endif
#include "fs_context.h"
#include "cached_dir.h"
@@ -1198,4 +1199,69 @@ int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
return 0;
}
+
+/*
+ * Handle weird Windows SMB server behaviour. It responds with
+ * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request for
+ * "\<server>\<dfsname>\<linkpath>" DFS reference, where <dfsname> contains
+ * non-ASCII unicode symbols.
+ */
+int cifs_inval_name_dfs_link_error(const unsigned int xid,
+ struct cifs_tcon *tcon,
+ struct cifs_sb_info *cifs_sb,
+ const char *full_path,
+ bool *islink)
+{
+ struct cifs_ses *ses = tcon->ses;
+ size_t len;
+ char *path;
+ char *ref_path;
+
+ *islink = false;
+
+ /*
+ * Fast path - skip check when @full_path doesn't have a prefix path to
+ * look up or tcon is not DFS.
+ */
+ if (strlen(full_path) < 2 || !cifs_sb ||
+ (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) ||
+ !is_tcon_dfs(tcon) || !ses->server->origin_fullpath)
+ return 0;
+
+ /*
+ * Slow path - tcon is DFS and @full_path has prefix path, so attempt
+ * to get a referral to figure out whether it is an DFS link.
+ */
+ len = strnlen(tcon->tree_name, MAX_TREE_SIZE + 1) + strlen(full_path) + 1;
+ path = kmalloc(len, GFP_KERNEL);
+ if (!path)
+ return -ENOMEM;
+
+ scnprintf(path, len, "%s%s", tcon->tree_name, full_path);
+ ref_path = dfs_cache_canonical_path(path + 1, cifs_sb->local_nls,
+ cifs_remap(cifs_sb));
+ if (IS_ERR(ref_path)) {
+ if (PTR_ERR(ref_path) != -EINVAL)
+ return PTR_ERR(ref_path);
+ } else if (ses->server->ops->get_dfs_refer) {
+ struct dfs_info3_param *refs = NULL;
+ int num_refs = 0;
+
+ /*
+ * XXX: we are not using dfs_cache_find() here because we might
+ * end filling all the DFS cache and thus potentially
+ * removing cached DFS targets that the client would eventually
+ * need during failover.
+ */
+ if (!ses->server->ops->get_dfs_refer(xid, ses, ref_path, &refs,
+ &num_refs, cifs_sb->local_nls,
+ cifs_remap(cifs_sb)))
+ *islink = refs[0].server_type == DFS_TYPE_LINK;
+ free_dfs_info_array(refs, num_refs);
+ kfree(ref_path);
+ }
+
+ kfree(path);
+ return 0;
+}
#endif
diff --git a/fs/cifs/smb2inode.c b/fs/cifs/smb2inode.c
index 37b4cd59245d..9b956294e864 100644
--- a/fs/cifs/smb2inode.c
+++ b/fs/cifs/smb2inode.c
@@ -527,12 +527,13 @@ int smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
struct cifs_sb_info *cifs_sb, const char *full_path,
struct cifs_open_info_data *data, bool *adjust_tz, bool *reparse)
{
- int rc;
__u32 create_options = 0;
struct cifsFileInfo *cfile;
struct cached_fid *cfid = NULL;
struct kvec err_iov[3] = {};
int err_buftype[3] = {};
+ bool islink;
+ int rc, rc2;
*adjust_tz = false;
*reparse = false;
@@ -580,15 +581,15 @@ int smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
SMB2_OP_QUERY_INFO, cfile, NULL, NULL,
NULL, NULL);
goto out;
- } else if (rc != -EREMOTE && IS_ENABLED(CONFIG_CIFS_DFS_UPCALL) &&
- hdr->Status == STATUS_OBJECT_NAME_INVALID) {
- /*
- * Handle weird Windows SMB server behaviour. It responds with
- * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request
- * for "\<server>\<dfsname>\<linkpath>" DFS reference,
- * where <dfsname> contains non-ASCII unicode symbols.
- */
- rc = -EREMOTE;
+ } else if (rc != -EREMOTE && hdr->Status == STATUS_OBJECT_NAME_INVALID) {
+ rc2 = cifs_inval_name_dfs_link_error(xid, tcon, cifs_sb,
+ full_path, &islink);
+ if (rc2) {
+ rc = rc2;
+ goto out;
+ }
+ if (islink)
+ rc = -EREMOTE;
}
if (rc == -EREMOTE && IS_ENABLED(CONFIG_CIFS_DFS_UPCALL) && cifs_sb &&
(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS))
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index f79b075f2992..6dfb865ee9d7 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -796,7 +796,6 @@ static int
smb2_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
struct cifs_sb_info *cifs_sb, const char *full_path)
{
- int rc;
__le16 *utf16_path;
__u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
int err_buftype = CIFS_NO_BUFFER;
@@ -804,6 +803,8 @@ smb2_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
struct kvec err_iov = {};
struct cifs_fid fid;
struct cached_fid *cfid;
+ bool islink;
+ int rc, rc2;
rc = open_cached_dir(xid, tcon, full_path, cifs_sb, true, &cfid);
if (!rc) {
@@ -833,15 +834,17 @@ smb2_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
if (unlikely(!hdr || err_buftype == CIFS_NO_BUFFER))
goto out;
- /*
- * Handle weird Windows SMB server behaviour. It responds with
- * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request
- * for "\<server>\<dfsname>\<linkpath>" DFS reference,
- * where <dfsname> contains non-ASCII unicode symbols.
- */
- if (rc != -EREMOTE && IS_ENABLED(CONFIG_CIFS_DFS_UPCALL) &&
- hdr->Status == STATUS_OBJECT_NAME_INVALID)
- rc = -EREMOTE;
+
+ if (rc != -EREMOTE && hdr->Status == STATUS_OBJECT_NAME_INVALID) {
+ rc2 = cifs_inval_name_dfs_link_error(xid, tcon, cifs_sb,
+ full_path, &islink);
+ if (rc2) {
+ rc = rc2;
+ goto out;
+ }
+ if (islink)
+ rc = -EREMOTE;
+ }
if (rc == -EREMOTE && IS_ENABLED(CONFIG_CIFS_DFS_UPCALL) && cifs_sb &&
(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS))
rc = -EOPNOTSUPP;
--
2.39.2
