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cifs: improve checking of DFS links over STATUS_OBJECT_NAME_INVALID

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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: c877ce47e1 ("cifs: reduce roundtrips on create/qinfo requests")
CC: stable@vger.kernel.org # 6.2
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Paulo Alcantara 2023-02-28 19:01:54 -03:00 committed by Steve French
parent 4c0421fa6d
commit b9ee2e307c
4 changed files with 106 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
fs/cifs/cifsproto.h
View File

@ -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)

67
fs/cifs/misc.c
View File

@ -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 +1199,70 @@ 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));
kfree(path);
if (IS_ERR(ref_path)) {
if (PTR_ERR(ref_path) != -EINVAL)
return PTR_ERR(ref_path);
} else {
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 &&
!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);
}
return 0;
}
#endif

21
fs/cifs/smb2inode.c
View File

@ -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))

23
fs/cifs/smb2ops.c
View File

@ -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;