From: Paulo Alcantara pc@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) pc@cjr.nz Cc: stable@vger.kernel.org # 5.11 Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@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;