Some notable changes, from upstream's release notes: - sshd(8): Remove support for obsolete "host/port" syntax. - ssh(1): When prompting whether to record a new host key, accept the key fingerprint as a synonym for "yes". - ssh-keygen(1): when acting as a CA and signing certificates with an RSA key, default to using the rsa-sha2-512 signature algorithm. - ssh(1), sshd(8), ssh-keygen(1): this release removes the "ssh-rsa" (RSA/SHA1) algorithm from those accepted for certificate signatures. - ssh-sk-helper(8): this is a new binary. It is used by the FIDO/U2F support to provide address-space isolation for token middleware libraries (including the internal one). - ssh(1): this release enables UpdateHostkeys by default subject to some conservative preconditions. - scp(1): this release changes the behaviour of remote to remote copies (e.g. "scp host-a:/path host-b:") to transfer through the local host by default. - scp(1): experimental support for transfers using the SFTP protocol as a replacement for the venerable SCP/RCP protocol that it has traditionally used. Additional integration work is needed to support FIDO/U2F in the base system. Deprecation Notice ------------------ OpenSSH will disable the ssh-rsa signature scheme by default in the next release. Reviewed by: imp MFC after: 1 month Relnotes: Yes Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D29985
227 lines
6.0 KiB
C
227 lines
6.0 KiB
C
/* $OpenBSD: sftp-realpath.c,v 1.1 2019/07/05 04:55:40 djm Exp $ */
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/*
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* Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The names of the authors may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "includes.h"
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/stat.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <stddef.h>
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#include <string.h>
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#include <unistd.h>
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#include <limits.h>
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#ifndef SYMLOOP_MAX
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# define SYMLOOP_MAX 32
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#endif
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/* XXX rewrite sftp-server to use POSIX realpath and remove this hack */
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char *sftp_realpath(const char *path, char *resolved);
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/*
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* char *realpath(const char *path, char resolved[PATH_MAX]);
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*
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* Find the real name of path, by removing all ".", ".." and symlink
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* components. Returns (resolved) on success, or (NULL) on failure,
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* in which case the path which caused trouble is left in (resolved).
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*/
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char *
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sftp_realpath(const char *path, char *resolved)
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{
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struct stat sb;
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char *p, *q, *s;
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size_t left_len, resolved_len;
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unsigned symlinks;
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int serrno, slen, mem_allocated;
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char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
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if (path[0] == '\0') {
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errno = ENOENT;
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return (NULL);
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}
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serrno = errno;
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if (resolved == NULL) {
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resolved = malloc(PATH_MAX);
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if (resolved == NULL)
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return (NULL);
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mem_allocated = 1;
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} else
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mem_allocated = 0;
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symlinks = 0;
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if (path[0] == '/') {
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resolved[0] = '/';
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resolved[1] = '\0';
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if (path[1] == '\0')
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return (resolved);
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resolved_len = 1;
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left_len = strlcpy(left, path + 1, sizeof(left));
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} else {
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if (getcwd(resolved, PATH_MAX) == NULL) {
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if (mem_allocated)
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free(resolved);
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else
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strlcpy(resolved, ".", PATH_MAX);
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return (NULL);
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}
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resolved_len = strlen(resolved);
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left_len = strlcpy(left, path, sizeof(left));
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}
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if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) {
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errno = ENAMETOOLONG;
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goto err;
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}
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/*
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* Iterate over path components in `left'.
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*/
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while (left_len != 0) {
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/*
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* Extract the next path component and adjust `left'
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* and its length.
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*/
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p = strchr(left, '/');
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s = p ? p : left + left_len;
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if (s - left >= (ptrdiff_t)sizeof(next_token)) {
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errno = ENAMETOOLONG;
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goto err;
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}
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memcpy(next_token, left, s - left);
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next_token[s - left] = '\0';
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left_len -= s - left;
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if (p != NULL)
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memmove(left, s + 1, left_len + 1);
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if (resolved[resolved_len - 1] != '/') {
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if (resolved_len + 1 >= PATH_MAX) {
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errno = ENAMETOOLONG;
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goto err;
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}
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resolved[resolved_len++] = '/';
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resolved[resolved_len] = '\0';
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}
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if (next_token[0] == '\0')
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continue;
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else if (strcmp(next_token, ".") == 0)
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continue;
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else if (strcmp(next_token, "..") == 0) {
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/*
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* Strip the last path component except when we have
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* single "/"
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*/
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if (resolved_len > 1) {
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resolved[resolved_len - 1] = '\0';
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q = strrchr(resolved, '/') + 1;
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*q = '\0';
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resolved_len = q - resolved;
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}
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continue;
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}
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/*
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* Append the next path component and lstat() it. If
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* lstat() fails we still can return successfully if
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* there are no more path components left.
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*/
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resolved_len = strlcat(resolved, next_token, PATH_MAX);
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if (resolved_len >= PATH_MAX) {
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errno = ENAMETOOLONG;
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goto err;
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}
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if (lstat(resolved, &sb) != 0) {
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if (errno == ENOENT && p == NULL) {
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errno = serrno;
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return (resolved);
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}
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goto err;
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}
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if (S_ISLNK(sb.st_mode)) {
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if (symlinks++ > SYMLOOP_MAX) {
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errno = ELOOP;
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goto err;
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}
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slen = readlink(resolved, symlink, sizeof(symlink) - 1);
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if (slen < 0)
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goto err;
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symlink[slen] = '\0';
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if (symlink[0] == '/') {
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resolved[1] = 0;
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resolved_len = 1;
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} else if (resolved_len > 1) {
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/* Strip the last path component. */
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resolved[resolved_len - 1] = '\0';
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q = strrchr(resolved, '/') + 1;
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*q = '\0';
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resolved_len = q - resolved;
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}
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/*
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* If there are any path components left, then
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* append them to symlink. The result is placed
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* in `left'.
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*/
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if (p != NULL) {
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if (symlink[slen - 1] != '/') {
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if (slen + 1 >=
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(ptrdiff_t)sizeof(symlink)) {
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errno = ENAMETOOLONG;
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goto err;
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}
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symlink[slen] = '/';
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symlink[slen + 1] = 0;
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}
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left_len = strlcat(symlink, left, sizeof(symlink));
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if (left_len >= sizeof(symlink)) {
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errno = ENAMETOOLONG;
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goto err;
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}
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}
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left_len = strlcpy(left, symlink, sizeof(left));
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}
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}
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/*
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* Remove trailing slash except when the resolved pathname
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* is a single "/".
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*/
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if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
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resolved[resolved_len - 1] = '\0';
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return (resolved);
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err:
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if (mem_allocated)
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free(resolved);
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return (NULL);
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}
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