From: Paulo Alcantara pc@manguebit.com
commit b9ee2e307c6b06384b6f9e393a9b8e048e8fc277 upstream.
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") 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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/cifs/cifsproto.h | 20 +++++++++++---- fs/cifs/misc.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/cifs/smb2inode.c | 21 ++++++++-------- fs/cifs/smb2ops.c | 23 ++++++++++------- 4 files changed, 106 insertions(+), 25 deletions(-)
--- a/fs/cifs/cifsproto.h +++ b/fs/cifs/cifsproto.h @@ -670,11 +670,21 @@ static inline int get_dfs_path(const uns 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) --- 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" @@ -1300,4 +1301,70 @@ int cifs_update_super_prepath(struct cif 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 --- a/fs/cifs/smb2inode.c +++ b/fs/cifs/smb2inode.c @@ -526,12 +526,13 @@ int smb2_query_path_info(const unsigned 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; @@ -579,15 +580,15 @@ int smb2_query_path_info(const unsigned 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)) --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -794,7 +794,6 @@ 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; @@ -802,6 +801,8 @@ smb2_is_path_accessible(const unsigned i 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) { @@ -830,15 +831,17 @@ smb2_is_path_accessible(const unsigned i
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;