upstream: SFTP protocol extension to allow the server to expand
~-prefixed paths, in particular ~user ones. Allows scp in sftp mode to accept these paths, like scp in rcp mode does. prompted by and much discussion deraadt@ ok markus@ OpenBSD-Commit-ID: 7d794def9e4de348e1e777f6030fc9bafdfff392
This commit is contained in:
djm@openbsd.org
Damien Miller
parent
41b019ac06
commit
2ab864010e
21
PROTOCOL
21
PROTOCOL
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@ -525,6 +525,25 @@ limits.
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This extension is advertised in the SSH_FXP_VERSION hello with version
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"1".
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3.9. sftp: Extension request "expand-path@openssh.com"
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This request supports canonicalisation of relative paths and
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those that need tilde-expansion, i.e. "~", "~/..." and "~user/..."
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These paths are expanded using shell-like rules and the resultant
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path is canonicalised similarly to SSH2_FXP_REALPATH.
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It is implemented as a SSH_FXP_EXTENDED request with the following
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format:
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uint32 id
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string "expand-path@openssh.com"
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string path
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Its reply is the same format as that of SSH2_FXP_REALPATH.
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This extension is advertised in the SSH_FXP_VERSION hello with version
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"1".
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4. Miscellaneous changes
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4.1 Public key format
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@ -556,4 +575,4 @@ OpenSSH's connection multiplexing uses messages as described in
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PROTOCOL.mux over a Unix domain socket for communications between a
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master instance and later clients.
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$OpenBSD: PROTOCOL,v 1.41 2021/02/18 02:49:35 djm Exp $
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$OpenBSD: PROTOCOL,v 1.42 2021/08/09 23:47:44 djm Exp $
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49
misc.c
49
misc.c
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@ -1,4 +1,4 @@
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/* $OpenBSD: misc.c,v 1.168 2021/07/12 06:22:57 dtucker Exp $ */
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/* $OpenBSD: misc.c,v 1.169 2021/08/09 23:47:44 djm Exp $ */
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/*
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* Copyright (c) 2000 Markus Friedl. All rights reserved.
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* Copyright (c) 2005-2020 Damien Miller. All rights reserved.
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@ -1115,29 +1115,37 @@ freeargs(arglist *args)
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* Expands tildes in the file name. Returns data allocated by xmalloc.
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* Warning: this calls getpw*.
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*/
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char *
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tilde_expand_filename(const char *filename, uid_t uid)
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int
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tilde_expand(const char *filename, uid_t uid, char **retp)
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{
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const char *path, *sep;
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char user[128], *ret;
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struct passwd *pw;
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u_int len, slash;
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if (*filename != '~')
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return (xstrdup(filename));
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if (*filename != '~') {
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*retp = xstrdup(filename);
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return 0;
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}
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filename++;
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path = strchr(filename, '/');
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if (path != NULL && path > filename) { /* ~user/path */
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slash = path - filename;
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if (slash > sizeof(user) - 1)
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fatal("tilde_expand_filename: ~username too long");
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if (slash > sizeof(user) - 1) {
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error_f("~username too long");
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return -1;
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}
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memcpy(user, filename, slash);
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user[slash] = '\0';
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if ((pw = getpwnam(user)) == NULL)
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fatal("tilde_expand_filename: No such user %s", user);
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} else if ((pw = getpwuid(uid)) == NULL) /* ~/path */
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fatal("tilde_expand_filename: No such uid %ld", (long)uid);
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if ((pw = getpwnam(user)) == NULL) {
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error_f("No such user %s", user);
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return -1;
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}
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} else if ((pw = getpwuid(uid)) == NULL) { /* ~/path */
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error_f("No such uid %ld", (long)uid);
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return -1;
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}
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/* Make sure directory has a trailing '/' */
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len = strlen(pw->pw_dir);
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@ -1150,10 +1158,23 @@ tilde_expand_filename(const char *filename, uid_t uid)
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if (path != NULL)
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filename = path + 1;
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if (xasprintf(&ret, "%s%s%s", pw->pw_dir, sep, filename) >= PATH_MAX)
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fatal("tilde_expand_filename: Path too long");
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if (xasprintf(&ret, "%s%s%s", pw->pw_dir, sep, filename) >= PATH_MAX) {
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error_f("Path too long");
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return -1;
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}
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return (ret);
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*retp = ret;
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return 0;
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}
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char *
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tilde_expand_filename(const char *filename, uid_t uid)
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{
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char *ret;
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if (tilde_expand(filename, uid, &ret) != 0)
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cleanup_exit(255);
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return ret;
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}
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/*
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3
misc.h
3
misc.h
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@ -1,4 +1,4 @@
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/* $OpenBSD: misc.h,v 1.97 2021/06/08 06:54:40 djm Exp $ */
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/* $OpenBSD: misc.h,v 1.98 2021/08/09 23:47:44 djm Exp $ */
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/*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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@ -71,6 +71,7 @@ int parse_user_host_port(const char *, char **, char **, int *);
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int parse_uri(const char *, const char *, char **, char **, int *, char **);
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int convtime(const char *);
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const char *fmt_timeframe(time_t t);
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int tilde_expand(const char *, uid_t, char **);
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char *tilde_expand_filename(const char *, uid_t);
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char *dollar_expand(int *, const char *string, ...);
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17
scp.c
17
scp.c
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@ -1,4 +1,4 @@
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/* $OpenBSD: scp.c,v 1.226 2021/08/09 23:44:32 djm Exp $ */
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/* $OpenBSD: scp.c,v 1.227 2021/08/09 23:47:44 djm Exp $ */
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/*
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* scp - secure remote copy. This is basically patched BSD rcp which
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* uses ssh to do the data transfer (instead of using rcmd).
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@ -1255,10 +1255,14 @@ tolocal(int argc, char **argv, enum scp_mode_e mode, char *sftp_direct)
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/* Canonicalise a remote path, handling ~ by assuming cwd is the homedir */
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static char *
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absolute_remote_path(const char *path, const char *remote_path)
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absolute_remote_path(struct sftp_conn *conn, const char *path,
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const char *remote_path)
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{
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char *ret;
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if (can_expand_path(conn))
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return do_expand_path(conn, path);
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/* Handle ~ prefixed paths */
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if (*path != '~')
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ret = xstrdup(path);
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@ -1296,7 +1300,7 @@ source_sftp(int argc, char *src, char *targ,
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* No need to glob here - the local shell already took care of
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* the expansions
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*/
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if ((target = absolute_remote_path(targ, *remote_path)) == NULL)
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if ((target = absolute_remote_path(conn, targ, *remote_path)) == NULL)
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cleanup_exit(255);
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target_is_dir = remote_is_dir(conn, target);
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if (targetshouldbedirectory && !target_is_dir) {
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@ -1508,7 +1512,7 @@ sink_sftp(int argc, char *dst, const char *src, struct sftp_conn *conn)
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goto out;
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}
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if ((abs_src = absolute_remote_path(src, remote_path)) == NULL) {
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if ((abs_src = absolute_remote_path(conn, src, remote_path)) == NULL) {
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err = -1;
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goto out;
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}
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@ -1920,8 +1924,9 @@ throughlocal_sftp(struct sftp_conn *from, struct sftp_conn *to,
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if ((filename = basename(src)) == NULL)
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fatal("basename %s: %s", src, strerror(errno));
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if ((abs_src = absolute_remote_path(src, from_remote_path)) == NULL ||
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(target = absolute_remote_path(targ, *to_remote_path)) == NULL)
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if ((abs_src = absolute_remote_path(from, src,
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from_remote_path)) == NULL ||
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(target = absolute_remote_path(to, targ, *to_remote_path)) == NULL)
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cleanup_exit(255);
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free(from_remote_path);
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memset(&g, 0, sizeof(g));
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@ -1,4 +1,4 @@
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/* $OpenBSD: sftp-client.c,v 1.153 2021/08/09 07:16:09 djm Exp $ */
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/* $OpenBSD: sftp-client.c,v 1.154 2021/08/09 23:47:44 djm Exp $ */
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/*
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* Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
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*
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@ -102,6 +102,7 @@ struct sftp_conn {
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#define SFTP_EXT_FSYNC 0x00000010
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#define SFTP_EXT_LSETSTAT 0x00000020
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#define SFTP_EXT_LIMITS 0x00000040
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#define SFTP_EXT_PATH_EXPAND 0x00000080
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u_int exts;
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u_int64_t limit_kbps;
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struct bwlimit bwlimit_in, bwlimit_out;
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@ -529,6 +530,10 @@ do_init(int fd_in, int fd_out, u_int transfer_buflen, u_int num_requests,
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strcmp((char *)value, "1") == 0) {
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ret->exts |= SFTP_EXT_LIMITS;
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known = 1;
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} else if (strcmp(name, "expand-path@openssh.com") == 0 &&
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strcmp((char *)value, "1") == 0) {
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ret->exts |= SFTP_EXT_PATH_EXPAND;
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known = 1;
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}
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if (known) {
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debug2("Server supports extension \"%s\" revision %s",
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@ -964,8 +969,9 @@ do_fsetstat(struct sftp_conn *conn, const u_char *handle, u_int handle_len,
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return status == SSH2_FX_OK ? 0 : -1;
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}
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char *
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do_realpath(struct sftp_conn *conn, const char *path)
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/* Implements both the realpath and expand-path operations */
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static char *
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do_realpath_expand(struct sftp_conn *conn, const char *path, int expand)
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{
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struct sshbuf *msg;
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u_int expected_id, count, id;
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@ -973,14 +979,26 @@ do_realpath(struct sftp_conn *conn, const char *path)
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Attrib a;
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u_char type;
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int r;
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const char *what = "SSH2_FXP_REALPATH";
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expected_id = id = conn->msg_id++;
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send_string_request(conn, id, SSH2_FXP_REALPATH, path,
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strlen(path));
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if (expand)
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what = "expand-path@openssh.com";
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if ((msg = sshbuf_new()) == NULL)
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fatal_f("sshbuf_new failed");
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expected_id = id = conn->msg_id++;
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if (expand) {
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if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED)) != 0 ||
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(r = sshbuf_put_u32(msg, id)) != 0 ||
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(r = sshbuf_put_cstring(msg,
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"expand-path@openssh.com")) != 0 ||
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(r = sshbuf_put_cstring(msg, path)) != 0)
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fatal_fr(r, "compose %s", what);
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send_msg(conn, msg);
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} else {
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send_string_request(conn, id, SSH2_FXP_REALPATH,
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path, strlen(path));
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}
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get_msg(conn, msg);
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if ((r = sshbuf_get_u8(msg, &type)) != 0 ||
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(r = sshbuf_get_u32(msg, &id)) != 0)
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@ -1004,15 +1022,14 @@ do_realpath(struct sftp_conn *conn, const char *path)
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if ((r = sshbuf_get_u32(msg, &count)) != 0)
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fatal_fr(r, "parse count");
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if (count != 1)
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fatal("Got multiple names (%d) from SSH_FXP_REALPATH", count);
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fatal("Got multiple names (%d) from %s", count, what);
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if ((r = sshbuf_get_cstring(msg, &filename, NULL)) != 0 ||
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(r = sshbuf_get_cstring(msg, &longname, NULL)) != 0 ||
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(r = decode_attrib(msg, &a)) != 0)
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fatal_fr(r, "parse filename/attrib");
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debug3("SSH_FXP_REALPATH %s -> %s size %lu", path, filename,
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(unsigned long)a.size);
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debug3("%s %s -> %s", what, path, filename);
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free(longname);
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@ -1021,6 +1038,28 @@ do_realpath(struct sftp_conn *conn, const char *path)
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return(filename);
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}
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char *
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do_realpath(struct sftp_conn *conn, const char *path)
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{
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return do_realpath_expand(conn, path, 0);
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}
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int
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can_expand_path(struct sftp_conn *conn)
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{
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return (conn->exts & SFTP_EXT_PATH_EXPAND) != 0;
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}
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char *
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do_expand_path(struct sftp_conn *conn, const char *path)
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{
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if (!can_expand_path(conn)) {
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debug3_f("no server support, fallback to realpath");
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return do_realpath_expand(conn, path, 0);
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}
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return do_realpath_expand(conn, path, 1);
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}
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int
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do_rename(struct sftp_conn *conn, const char *oldpath, const char *newpath,
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int force_legacy)
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@ -1,4 +1,4 @@
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/* $OpenBSD: sftp-client.h,v 1.33 2021/08/07 00:12:09 djm Exp $ */
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/* $OpenBSD: sftp-client.h,v 1.34 2021/08/09 23:47:44 djm Exp $ */
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/*
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* Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
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@ -113,11 +113,17 @@ int do_lsetstat(struct sftp_conn *conn, const char *path, Attrib *a);
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/* Canonicalise 'path' - caller must free result */
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char *do_realpath(struct sftp_conn *, const char *);
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/* Canonicalisation with tilde expansion (requires server extension) */
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char *do_expand_path(struct sftp_conn *, const char *);
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/* Returns non-zero if server can tilde-expand paths */
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int can_expand_path(struct sftp_conn *);
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/* Get statistics for filesystem hosting file at "path" */
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int do_statvfs(struct sftp_conn *, const char *, struct sftp_statvfs *, int);
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/* Rename 'oldpath' to 'newpath' */
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int do_rename(struct sftp_conn *, const char *, const char *, int force_legacy);
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int do_rename(struct sftp_conn *, const char *, const char *, int);
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/* Link 'oldpath' to 'newpath' */
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int do_hardlink(struct sftp_conn *, const char *, const char *);
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|
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@ -1,4 +1,4 @@
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/* $OpenBSD: sftp-server.c,v 1.128 2021/06/06 03:15:39 djm Exp $ */
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/* $OpenBSD: sftp-server.c,v 1.129 2021/08/09 23:47:44 djm Exp $ */
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/*
|
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* Copyright (c) 2000-2004 Markus Friedl. All rights reserved.
|
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*
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@ -115,6 +115,7 @@ static void process_extended_hardlink(u_int32_t id);
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static void process_extended_fsync(u_int32_t id);
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static void process_extended_lsetstat(u_int32_t id);
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static void process_extended_limits(u_int32_t id);
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static void process_extended_expand(u_int32_t id);
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static void process_extended(u_int32_t id);
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struct sftp_handler {
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@ -158,6 +159,8 @@ static const struct sftp_handler extended_handlers[] = {
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{ "fsync", "fsync@openssh.com", 0, process_extended_fsync, 1 },
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{ "lsetstat", "lsetstat@openssh.com", 0, process_extended_lsetstat, 1 },
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{ "limits", "limits@openssh.com", 0, process_extended_limits, 0 },
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{ "expand-path", "expand-path@openssh.com", 0,
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process_extended_expand, 0 },
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{ NULL, NULL, 0, NULL, 0 }
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};
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@ -706,6 +709,7 @@ process_init(void)
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compose_extension(msg, "fsync@openssh.com", "1");
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compose_extension(msg, "lsetstat@openssh.com", "1");
|
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compose_extension(msg, "limits@openssh.com", "1");
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compose_extension(msg, "expand-path@openssh.com", "1");
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send_msg(msg);
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sshbuf_free(msg);
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@ -1519,6 +1523,63 @@ process_extended_limits(u_int32_t id)
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sshbuf_free(msg);
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}
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|
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static void
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process_extended_expand(u_int32_t id)
|
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{
|
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char cwd[PATH_MAX], resolvedname[PATH_MAX];
|
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char *path, *npath;
|
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int r;
|
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Stat s;
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|
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if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
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fatal_fr(r, "parse");
|
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if (getcwd(cwd, sizeof(cwd)) == NULL) {
|
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send_status(id, errno_to_portable(errno));
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goto out;
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}
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|
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debug3("request %u: expand, original \"%s\"", id, path);
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if (path[0] == '\0') {
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/* empty path */
|
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free(path);
|
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path = xstrdup(".");
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} else if (*path == '~') {
|
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/* ~ expand path */
|
||||
/* Special-case for "~" and "~/" to respect homedir flag */
|
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if (strcmp(path, "~") == 0) {
|
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free(path);
|
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path = xstrdup(cwd);
|
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} else if (strncmp(path, "~/", 2) == 0) {
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npath = xstrdup(path + 2);
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free(path);
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xasprintf(&path, "%s/%s", cwd, npath);
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} else {
|
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/* ~user expansions */
|
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if (tilde_expand(path, pw->pw_uid, &npath) != 0) {
|
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send_status(id, errno_to_portable(EINVAL));
|
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goto out;
|
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}
|
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free(path);
|
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path = npath;
|
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}
|
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} else if (*path != '/') {
|
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/* relative path */
|
||||
xasprintf(&npath, "%s/%s", cwd, path);
|
||||
free(path);
|
||||
path = npath;
|
||||
}
|
||||
verbose("expand \"%s\"", path);
|
||||
if (sftp_realpath(path, resolvedname) == NULL) {
|
||||
send_status(id, errno_to_portable(errno));
|
||||
goto out;
|
||||
}
|
||||
attrib_clear(&s.attrib);
|
||||
s.name = s.long_name = resolvedname;
|
||||
send_names(id, 1, &s);
|
||||
out:
|
||||
free(path);
|
||||
}
|
||||
|
||||
static void
|
||||
process_extended(u_int32_t id)
|
||||
{
|
||||
|
|
|
|||
Loading…
Reference in New Issue