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Commit eb85d94b authored by Pavel Shilovsky's avatar Pavel Shilovsky Committed by Steve French
Browse files

CIFS: Fix symbolic links usage 



Now we treat any reparse point as a symbolic link and map it to a Unix
one that is not true in a common case due to many reparse point types
supported by SMB servers.

Distinguish reparse point types into two groups:
1) that can be accessed directly through a reparse point
(junctions, deduplicated files, NFS symlinks);
2) that need to be processed manually (Windows symbolic links, DFS);

and map only Windows symbolic links to Unix ones.

Cc: <stable@vger.kernel.org>
Acked-by: default avatarJeff Layton <jlayton@redhat.com>
Reported-and-tested-by: default avatarJoao Correia <joaomiguelcorreia@gmail.com>
Signed-off-by: default avatarPavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
parent 6c86ae29

fs/cifs/cifsglob.h

+1 −1
Original line number Diff line number Diff line
@@ -261,7 +261,7 @@ struct smb_version_operations { 
	/* query path data from the server */

	int (*query_path_info)(const unsigned int, struct cifs_tcon *,

			       struct cifs_sb_info *, const char *,

			       FILE_ALL_INFO *, bool *);

			       FILE_ALL_INFO *, bool *, bool *);

	/* query file data from the server */

	int (*query_file_info)(const unsigned int, struct cifs_tcon *,

			       struct cifs_fid *, FILE_ALL_INFO *);

fs/cifs/inode.c

+13 −10
Original line number Diff line number Diff line
@@ -542,7 +542,8 @@ static int cifs_sfu_mode(struct cifs_fattr *fattr, const unsigned char *path, 
/* Fill a cifs_fattr struct with info from FILE_ALL_INFO */

static void

cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,

		       struct cifs_sb_info *cifs_sb, bool adjust_tz)

		       struct cifs_sb_info *cifs_sb, bool adjust_tz,

		       bool symlink)

{

	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
@@ -569,7 +570,11 @@ cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info, 
	fattr->cf_createtime = le64_to_cpu(info->CreationTime);



	fattr->cf_nlink = le32_to_cpu(info->NumberOfLinks);

	if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {



	if (symlink) {

		fattr->cf_mode = S_IFLNK;

		fattr->cf_dtype = DT_LNK;

	} else if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {

		fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;

		fattr->cf_dtype = DT_DIR;

		/*
@@ -578,10 +583,6 @@ cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info, 
		 */

		if (!tcon->unix_ext)

			fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;

	} 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;
@@ -626,7 +627,8 @@ cifs_get_file_info(struct file *filp) 
	rc = server->ops->query_file_info(xid, tcon, &cfile->fid, &find_data);

	switch (rc) {

	case 0:

		cifs_all_info_to_fattr(&fattr, &find_data, cifs_sb, false);

		cifs_all_info_to_fattr(&fattr, &find_data, cifs_sb, false,

				       false);

		break;

	case -EREMOTE:

		cifs_create_dfs_fattr(&fattr, inode->i_sb);
@@ -673,6 +675,7 @@ cifs_get_inode_info(struct inode **inode, const char *full_path, 
	bool adjust_tz = false;

	struct cifs_fattr fattr;

	struct cifs_search_info *srchinf = NULL;

	bool symlink = false;



	tlink = cifs_sb_tlink(cifs_sb);

	if (IS_ERR(tlink))
@@ -702,12 +705,12 @@ cifs_get_inode_info(struct inode **inode, const char *full_path, 
		}

		data = (FILE_ALL_INFO *)buf;

		rc = server->ops->query_path_info(xid, tcon, cifs_sb, full_path,

						  data, &adjust_tz);

						  data, &adjust_tz, &symlink);

	}



	if (!rc) {

		cifs_all_info_to_fattr(&fattr, (FILE_ALL_INFO *)data, cifs_sb,

				       adjust_tz);

		cifs_all_info_to_fattr(&fattr, data, cifs_sb, adjust_tz,

				       symlink);

	} else if (rc == -EREMOTE) {

		cifs_create_dfs_fattr(&fattr, sb);

		rc = 0;

fs/cifs/readdir.c

+8 −32
Original line number Diff line number Diff line
@@ -134,22 +134,6 @@ cifs_prime_dcache(struct dentry *parent, struct qstr *name, 
	dput(dentry);

}



/*

 * Is it possible that this directory might turn out to be a DFS referral

 * once we go to try and use it?

 */

static bool

cifs_dfs_is_possible(struct cifs_sb_info *cifs_sb)

{

#ifdef CONFIG_CIFS_DFS_UPCALL

	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);



	if (tcon->Flags & SMB_SHARE_IS_IN_DFS)

		return true;

#endif

	return false;

}



static void

cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)

{
@@ -159,27 +143,19 @@ cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb) 
	if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {

		fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;

		fattr->cf_dtype = DT_DIR;

		/*

		 * Windows CIFS servers generally make DFS referrals look

		 * like directories in FIND_* responses with the reparse

		 * attribute flag also set (since DFS junctions are

		 * reparse points). We must revalidate at least these

		 * directory inodes before trying to use them (if

		 * they are DFS we will get PATH_NOT_COVERED back

		 * when queried directly and can then try to connect

		 * to the DFS target)

		 */

		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;

	}



	/*

	 * We need to revalidate it further to make a decision about whether it

	 * is a symbolic link, DFS referral or a reparse point with a direct

	 * access like junctions, deduplicated files, NFS symlinks.

	 */

	if (fattr->cf_cifsattrs & ATTR_REPARSE)

		fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;



	/* non-unix readdir doesn't provide nlink */

	fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;

fs/cifs/smb1ops.c

+20 −1
Original line number Diff line number Diff line
@@ -534,10 +534,12 @@ cifs_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon, 
static int

cifs_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,

		     struct cifs_sb_info *cifs_sb, const char *full_path,

		     FILE_ALL_INFO *data, bool *adjustTZ)

		     FILE_ALL_INFO *data, bool *adjustTZ, bool *symlink)

{

	int rc;



	*symlink = false;



	/* could do find first instead but this returns more info */

	rc = CIFSSMBQPathInfo(xid, tcon, full_path, data, 0 /* not legacy */,

			      cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
@@ -554,6 +556,23 @@ cifs_query_path_info(const unsigned int xid, struct cifs_tcon *tcon, 
						CIFS_MOUNT_MAP_SPECIAL_CHR);

		*adjustTZ = true;

	}



	if (!rc && (le32_to_cpu(data->Attributes) & ATTR_REPARSE)) {

		int tmprc;

		int oplock = 0;

		__u16 netfid;



		/* Need to check if this is a symbolic link or not */

		tmprc = CIFSSMBOpen(xid, tcon, full_path, FILE_OPEN,

				    FILE_READ_ATTRIBUTES, 0, &netfid, &oplock,

				    NULL, cifs_sb->local_nls,

			cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);

		if (tmprc == -EOPNOTSUPP)

			*symlink = true;

		else

			CIFSSMBClose(xid, tcon, netfid);

	}



	return rc;

}

fs/cifs/smb2inode.c

+12 −4
Original line number Diff line number Diff line
@@ -123,22 +123,30 @@ move_smb2_info_to_cifs(FILE_ALL_INFO *dst, struct smb2_file_all_info *src) 
int

smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,

		     struct cifs_sb_info *cifs_sb, const char *full_path,

		     FILE_ALL_INFO *data, bool *adjust_tz)

		     FILE_ALL_INFO *data, bool *adjust_tz, bool *symlink)

{

	int rc;

	struct smb2_file_all_info *smb2_data;



	*adjust_tz = false;

	*symlink = false;



	smb2_data = kzalloc(sizeof(struct smb2_file_all_info) + MAX_NAME * 2,

			    GFP_KERNEL);

	if (smb2_data == NULL)

		return -ENOMEM;



	rc = smb2_open_op_close(xid, tcon, cifs_sb, full_path,

				FILE_READ_ATTRIBUTES, FILE_OPEN, 0,

				smb2_data, SMB2_OP_QUERY_INFO);

	if (rc == -EOPNOTSUPP) {

		*symlink = true;

		/* Failed on a symbolic link - query a reparse point info */

		rc = smb2_open_op_close(xid, tcon, cifs_sb, full_path,

					FILE_READ_ATTRIBUTES, FILE_OPEN,

					OPEN_REPARSE_POINT, smb2_data,

					SMB2_OP_QUERY_INFO);

	}

	if (rc)

		goto out;