On Fri, 9 Aug 2013 16:57:21 +0400
Pavel Shilovsky <pshilovsky@xxxxxxxxx> wrote:
> that allows to access files through symlink created on a server.
>
> Signed-off-by: Pavel Shilovsky <pshilovsky@xxxxxxxxx>
> ---
> fs/cifs/cifsglob.h | 3 +++
> fs/cifs/inode.c | 4 ++++
> fs/cifs/link.c | 24 +++++----------------
> fs/cifs/readdir.c | 3 +++
> fs/cifs/smb2file.c | 2 +-
> fs/cifs/smb2inode.c | 9 ++++----
> fs/cifs/smb2misc.c | 4 ++++
> fs/cifs/smb2ops.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++---
> fs/cifs/smb2pdu.c | 9 +++++++-
> fs/cifs/smb2pdu.h | 14 ++++++++++++
> fs/cifs/smb2proto.h | 3 ++-
> 11 files changed, 106 insertions(+), 29 deletions(-)
>
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 1b1b144..e96ba59 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -305,6 +305,9 @@ struct smb_version_operations {
> int (*create_hardlink)(const unsigned int, struct cifs_tcon *,
> const char *, const char *,
> struct cifs_sb_info *);
> + /* query symlink target */
> + int (*query_symlink)(const unsigned int, struct cifs_tcon *,
> + const char *, char **, struct cifs_sb_info *);
> /* open a file for non-posix mounts */
> int (*open)(const unsigned int, struct cifs_open_parms *,
> __u32 *, FILE_ALL_INFO *);
> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
> index 20efd81..f776fbf 100644
> --- a/fs/cifs/inode.c
> +++ b/fs/cifs/inode.c
> @@ -549,6 +549,10 @@ cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,
> * when Unix extensions are disabled - fake it.
> */
> fattr->cf_nlink = 2;
> + } else if (fattr->cf_cifsattrs & ATTR_REPARSE) {
> + fattr->cf_mode = S_IFLNK;
> + fattr->cf_dtype = DT_LNK;
> + fattr->cf_nlink = le32_to_cpu(info->NumberOfLinks);
> } else {
> fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
> fattr->cf_dtype = DT_REG;
> diff --git a/fs/cifs/link.c b/fs/cifs/link.c
> index b83c3f5..fd089f7 100644
> --- a/fs/cifs/link.c
> +++ b/fs/cifs/link.c
> @@ -487,6 +487,7 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
> struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
> struct tcon_link *tlink = NULL;
> struct cifs_tcon *tcon;
> + struct TCP_Server_Info *server;
>
> xid = get_xid();
>
> @@ -497,25 +498,7 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
> goto out;
> }
> tcon = tlink_tcon(tlink);
> -
> - /*
> - * For now, we just handle symlinks with unix extensions enabled.
> - * Eventually we should handle NTFS reparse points, and MacOS
> - * symlink support. For instance...
> - *
> - * rc = CIFSSMBQueryReparseLinkInfo(...)
> - *
> - * For now, just return -EACCES when the server doesn't support posix
> - * extensions. Note that we still allow querying symlinks when posix
> - * extensions are manually disabled. We could disable these as well
> - * but there doesn't seem to be any harm in allowing the client to
> - * read them.
> - */
> - if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
> - !cap_unix(tcon->ses)) {
> - rc = -EACCES;
> - goto out;
> - }
> + server = tcon->ses->server;
>
> full_path = build_path_from_dentry(direntry);
> if (!full_path)
> @@ -537,6 +520,9 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
> if ((rc != 0) && cap_unix(tcon->ses))
> rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
> cifs_sb->local_nls);
> + else if (rc != 0 && server->ops->query_symlink)
> + rc = server->ops->query_symlink(xid, tcon, full_path,
> + &target_path, cifs_sb);
>
> kfree(full_path);
> out:
> diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
> index 94d6201..38ceb51 100644
> --- a/fs/cifs/readdir.c
> +++ b/fs/cifs/readdir.c
> @@ -164,6 +164,9 @@ cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
> if (cifs_dfs_is_possible(cifs_sb) &&
> (fattr->cf_cifsattrs & ATTR_REPARSE))
> fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
> + } else if (fattr->cf_cifsattrs & ATTR_REPARSE) {
> + fattr->cf_mode = S_IFLNK;
> + fattr->cf_dtype = DT_LNK;
> } else {
> fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
> fattr->cf_dtype = DT_REG;
> diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
> index 04a81a4..020245d 100644
> --- a/fs/cifs/smb2file.c
> +++ b/fs/cifs/smb2file.c
> @@ -86,7 +86,7 @@ smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms,
> if (oparms->tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LEASING)
> memcpy(smb2_oplock + 1, fid->lease_key, SMB2_LEASE_KEY_SIZE);
>
> - rc = SMB2_open(xid, oparms, smb2_path, smb2_oplock, smb2_data);
> + rc = SMB2_open(xid, oparms, smb2_path, smb2_oplock, smb2_data, NULL);
So what happens if I run across one of these symlinks as the terminal
dentry of an atomic_open call? Does that just fail currently?
> if (rc)
> goto out;
>
> diff --git a/fs/cifs/smb2inode.c b/fs/cifs/smb2inode.c
> index c6ec163..78ff88c 100644
> --- a/fs/cifs/smb2inode.c
> +++ b/fs/cifs/smb2inode.c
> @@ -60,7 +60,7 @@ smb2_open_op_close(const unsigned int xid, struct cifs_tcon *tcon,
> oparms.fid = &fid;
> oparms.reconnect = false;
>
> - rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL);
> + rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL);
> if (rc) {
> kfree(utf16_path);
> return rc;
> @@ -136,7 +136,8 @@ smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
> return -ENOMEM;
>
> rc = smb2_open_op_close(xid, tcon, cifs_sb, full_path,
> - FILE_READ_ATTRIBUTES, FILE_OPEN, 0, smb2_data,
> + FILE_READ_ATTRIBUTES, FILE_OPEN,
> + OPEN_REPARSE_POINT, smb2_data,
> SMB2_OP_QUERY_INFO);
> if (rc)
> goto out;
> @@ -191,8 +192,8 @@ smb2_unlink(const unsigned int xid, struct cifs_tcon *tcon, const char *name,
> struct cifs_sb_info *cifs_sb)
> {
> return smb2_open_op_close(xid, tcon, cifs_sb, name, DELETE, FILE_OPEN,
> - CREATE_DELETE_ON_CLOSE, NULL,
> - SMB2_OP_DELETE);
> + CREATE_DELETE_ON_CLOSE | OPEN_REPARSE_POINT,
> + NULL, SMB2_OP_DELETE);
> }
>
> static int
> diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
> index b0c4334..6103359 100644
> --- a/fs/cifs/smb2misc.c
> +++ b/fs/cifs/smb2misc.c
> @@ -171,6 +171,10 @@ smb2_check_message(char *buf, unsigned int length)
> if (4 + len != clc_len) {
> cifs_dbg(FYI, "Calculated size %u length %u mismatch mid %llu\n",
> clc_len, 4 + len, mid);
> + /* create failed on symlink */
> + if (command == SMB2_CREATE_HE &&
> + hdr->Status == STATUS_STOPPED_ON_SYMLINK)
> + return 0;
> /* Windows 7 server returns 24 bytes more */
> if (clc_len + 20 == len && command == SMB2_OPLOCK_BREAK_HE)
> return 0;
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index 300ff85..66acbb3 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -24,6 +24,7 @@
> #include "smb2proto.h"
> #include "cifsproto.h"
> #include "cifs_debug.h"
> +#include "cifs_unicode.h"
> #include "smb2status.h"
> #include "smb2glob.h"
>
> @@ -229,7 +230,7 @@ smb2_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
> oparms.fid = &fid;
> oparms.reconnect = false;
>
> - rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL);
> + rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL);
> if (rc) {
> kfree(utf16_path);
> return rc;
> @@ -463,7 +464,7 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
> oparms.fid = fid;
> oparms.reconnect = false;
>
> - rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL);
> + rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL);
> kfree(utf16_path);
> if (rc) {
> cifs_dbg(VFS, "open dir failed\n");
> @@ -550,7 +551,7 @@ smb2_queryfs(const unsigned int xid, struct cifs_tcon *tcon,
> oparms.fid = &fid;
> oparms.reconnect = false;
>
> - rc = SMB2_open(xid, &oparms, &srch_path, &oplock, NULL);
> + rc = SMB2_open(xid, &oparms, &srch_path, &oplock, NULL, NULL);
> if (rc)
> return rc;
> buf->f_type = SMB2_MAGIC_NUMBER;
> @@ -596,6 +597,57 @@ smb2_new_lease_key(struct cifs_fid *fid)
> get_random_bytes(fid->lease_key, SMB2_LEASE_KEY_SIZE);
> }
>
> +int
> +smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
> + const char *full_path, char **target_path,
> + struct cifs_sb_info *cifs_sb)
> +{
> + int rc;
> + __le16 *utf16_path;
> + __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
> + struct cifs_open_parms oparms;
> + struct cifs_fid fid;
> + struct smb2_err_rsp *err_buf = NULL;
> + struct smb2_symlink_err_rsp *symlink;
> + unsigned int sub_len, sub_offset;
> +
> + cifs_dbg(FYI, "%s: path: %s\n", __func__, full_path);
> +
> + utf16_path = cifs_convert_path_to_utf16(full_path, cifs_sb);
> + if (!utf16_path)
> + return -ENOMEM;
> +
> + oparms.tcon = tcon;
> + oparms.desired_access = FILE_READ_ATTRIBUTES;
> + oparms.disposition = FILE_OPEN;
> + oparms.create_options = 0;
> + oparms.fid = &fid;
> + oparms.reconnect = false;
> +
> + rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, &err_buf);
> +
> + if (!rc || !err_buf) {
> + kfree(utf16_path);
> + return -ENOENT;
> + }
> + /* open must fail on symlink - reset rc */
> + rc = 0;
> + symlink = (struct smb2_symlink_err_rsp *)err_buf->ErrorData;
> + sub_len = le16_to_cpu(symlink->SubstituteNameLength);
> + sub_offset = le16_to_cpu(symlink->SubstituteNameOffset);
> + *target_path = cifs_strndup_from_utf16(
> + (char *)symlink->PathBuffer + sub_offset,
> + sub_len, true, cifs_sb->local_nls);
> + if (!(*target_path)) {
> + kfree(utf16_path);
> + return -ENOMEM;
> + }
> + convert_delimiter(*target_path, '/');
> + cifs_dbg(FYI, "%s: target path: %s\n", __func__, *target_path);
> + kfree(utf16_path);
> + return rc;
> +}
> +
> struct smb_version_operations smb21_operations = {
> .compare_fids = smb2_compare_fids,
> .setup_request = smb2_setup_request,
> @@ -638,6 +690,7 @@ struct smb_version_operations smb21_operations = {
> .unlink = smb2_unlink,
> .rename = smb2_rename_path,
> .create_hardlink = smb2_create_hardlink,
> + .query_symlink = smb2_query_symlink,
> .open = smb2_open_file,
> .set_fid = smb2_set_fid,
> .close = smb2_close_file,
> @@ -706,6 +759,7 @@ struct smb_version_operations smb30_operations = {
> .unlink = smb2_unlink,
> .rename = smb2_rename_path,
> .create_hardlink = smb2_create_hardlink,
> + .query_symlink = smb2_query_symlink,
> .open = smb2_open_file,
> .set_fid = smb2_set_fid,
> .close = smb2_close_file,
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index c7ad06f..e4a6e2d 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -977,7 +977,8 @@ add_durable_context(struct kvec *iov, unsigned int *num_iovec,
>
> int
> SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
> - __u8 *oplock, struct smb2_file_all_info *buf)
> + __u8 *oplock, struct smb2_file_all_info *buf,
> + struct smb2_err_rsp **err_buf)
> {
> struct smb2_create_req *req;
> struct smb2_create_rsp *rsp;
> @@ -1081,6 +1082,12 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
>
> if (rc != 0) {
> cifs_stats_fail_inc(tcon, SMB2_CREATE_HE);
> + if (err_buf) {
> + unsigned int buf_size = get_rfc1002_length(rsp) + 4;
> + *err_buf = kmalloc(buf_size, GFP_KERNEL);
> + if (*err_buf)
> + memcpy(*err_buf, rsp, buf_size);
> + }
This should be replaced with kmemdup().
> goto creat_exit;
> }
>
> diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
> index 36b0d37..40baeae 100644
> --- a/fs/cifs/smb2pdu.h
> +++ b/fs/cifs/smb2pdu.h
> @@ -150,6 +150,20 @@ struct smb2_err_rsp {
> __u8 ErrorData[1]; /* variable length */
> } __packed;
>
> +struct smb2_symlink_err_rsp {
> + __le32 SymLinkLength;
> + __le32 SymLinkErrorTag;
> + __le32 ReparseTag;
> + __le16 ReparseDataLength;
> + __le16 UnparsedPathLength;
> + __le16 SubstituteNameOffset;
> + __le16 SubstituteNameLength;
> + __le16 PrintNameOffset;
> + __le16 PrintNameLength;
> + __le32 Flags;
> + __u8 PathBuffer[0];
> +} __packed;
> +
> #define SMB2_CLIENT_GUID_SIZE 16
>
> extern __u8 cifs_client_guid[SMB2_CLIENT_GUID_SIZE];
> diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
> index 1a5ecbe..1db89fd 100644
> --- a/fs/cifs/smb2proto.h
> +++ b/fs/cifs/smb2proto.h
> @@ -106,7 +106,8 @@ extern int SMB2_tcon(const unsigned int xid, struct cifs_ses *ses,
> extern int SMB2_tdis(const unsigned int xid, struct cifs_tcon *tcon);
> extern int SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms,
> __le16 *path, __u8 *oplock,
> - struct smb2_file_all_info *buf);
> + struct smb2_file_all_info *buf,
> + struct smb2_err_rsp **err_buf);
> extern int SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon,
> u64 persistent_fid, u64 volatile_fid, u32 opcode,
> bool is_fsctl, char *in_data, u32 indatalen,
Looks fairly reasonable otherwise...
Acked-by: Jeff Layton <jlayton@xxxxxxxxxx>
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