From: Paulo Alcantara <p...@cjr.nz>
commit ff2c54a04097dee0b8899c485360719844d923f8 upstream.
Handle the case where a resolved target share is like
//server/users/dir, and the user "foo" has no read permission to
access the parent folder "users" but has access to the final path
component "dir".
is_path_remote() already implements that, so call it directly.
Signed-off-by: Paulo Alcantara (SUSE) <p...@cjr.nz>
Cc: sta...@vger.kernel.org # 5.11
Signed-off-by: Steve French <stfre...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
fs/cifs/connect.c | 93 +++++++++++++++++++-----------------------------------
1 file changed, 33 insertions(+), 60 deletions(-)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3280,73 +3280,46 @@ static void put_root_ses(struct cifs_ses
cifs_put_smb_ses(ses);
}
-/* Check if a path component is remote and then update @dfs_path accordingly */
-static int check_dfs_prepath(struct cifs_sb_info *cifs_sb, struct
smb3_fs_context *ctx,
- const unsigned int xid, struct TCP_Server_Info
*server,
- struct cifs_tcon *tcon, char **dfs_path)
+/* Set up next dfs prefix path in @dfs_path */
+static int next_dfs_prepath(struct cifs_sb_info *cifs_sb, struct
smb3_fs_context *ctx,
+ const unsigned int xid, struct TCP_Server_Info
*server,
+ struct cifs_tcon *tcon, char **dfs_path)
{
- char *path, *s;
- char sep = CIFS_DIR_SEP(cifs_sb), tmp;
- char *npath;
- int rc = 0;
- int added_treename = tcon->Flags & SMB_SHARE_IS_IN_DFS;
- int skip = added_treename;
+ char *path, *npath;
+ int added_treename = is_tcon_dfs(tcon);
+ int rc;
path = cifs_build_path_to_root(ctx, cifs_sb, tcon, added_treename);
if (!path)
return -ENOMEM;
- /*
- * Walk through the path components in @path and check if they're
accessible. In case any of
- * the components is -EREMOTE, then update @dfs_path with the next DFS
referral request path
- * (NOT including the remaining components).
- */
- s = path;
- do {
- /* skip separators */
- while (*s && *s == sep)
- s++;
- if (!*s)
- break;
- /* next separator */
- while (*s && *s != sep)
- s++;
- /*
- * if the treename is added, we then have to skip the first
- * part within the separators
- */
- if (skip) {
- skip = 0;
- continue;
+ rc = is_path_remote(cifs_sb, ctx, xid, server, tcon);
+ if (rc == -EREMOTE) {
+ struct smb3_fs_context v = {NULL};
+ /* if @path contains a tree name, skip it in the prefix path */
+ if (added_treename) {
+ rc = smb3_parse_devname(path, &v);
+ if (rc)
+ goto out;
+ npath = build_unc_path_to_root(&v, cifs_sb, true);
+ smb3_cleanup_fs_context_contents(&v);
+ } else {
+ v.UNC = ctx->UNC;
+ v.prepath = path + 1;
+ npath = build_unc_path_to_root(&v, cifs_sb, true);
}
- tmp = *s;
- *s = 0;
- rc = server->ops->is_path_accessible(xid, tcon, cifs_sb, path);
- if (rc && rc == -EREMOTE) {
- struct smb3_fs_context v = {NULL};
- /* if @path contains a tree name, skip it in the prefix
path */
- if (added_treename) {
- rc = smb3_parse_devname(path, &v);
- if (rc)
- break;
- rc = -EREMOTE;
- npath = build_unc_path_to_root(&v, cifs_sb,
true);
- smb3_cleanup_fs_context_contents(&v);
- } else {
- v.UNC = ctx->UNC;
- v.prepath = path + 1;
- npath = build_unc_path_to_root(&v, cifs_sb,
true);
- }
- if (IS_ERR(npath)) {
- rc = PTR_ERR(npath);
- break;
- }
- kfree(*dfs_path);
- *dfs_path = npath;
+
+ if (IS_ERR(npath)) {
+ rc = PTR_ERR(npath);
+ goto out;
}
- *s = tmp;
- } while (rc == 0);
+ kfree(*dfs_path);
+ *dfs_path = npath;
+ rc = -EREMOTE;
+ }
+
+out:
kfree(path);
return rc;
}
@@ -3432,8 +3405,8 @@ int cifs_mount(struct cifs_sb_info *cifs
put_root_ses(root_ses);
set_root_ses(cifs_sb, ses, &root_ses);
}
- /* Check for remaining path components and then continue
chasing them (-EREMOTE) */
- rc = check_dfs_prepath(cifs_sb, ctx, xid, server, tcon,
&ref_path);
+ /* Get next dfs path and then continue chasing them if -EREMOTE
*/
+ rc = next_dfs_prepath(cifs_sb, ctx, xid, server, tcon,
&ref_path);
/* Prevent recursion on broken link referrals */
if (rc == -EREMOTE && ++count > MAX_NESTED_LINKS)
rc = -ELOOP;
