Revision 3ec804490a265f4c418a321428c12f3f18b7eff5 authored by Jeff King on 29 April 2017, 12:36:44 UTC, committed by Junio C Hamano on 05 May 2017, 03:07:27 UTC
When a remote server uses git-shell, the client side will connect to it like: ssh server "git-upload-pack 'foo.git'" and we literally exec ("git-upload-pack", "foo.git"). In early versions of upload-pack and receive-pack, we took a repository argument and nothing else. But over time they learned to accept dashed options. If the user passes a repository name that starts with a dash, the results are confusing at best (we complain of a bogus option instead of a non-existent repository) and malicious at worst (the user can start an interactive pager via "--help"). We could pass "--" to the sub-process to make sure the user's argument is interpreted as a branch name. I.e.: git-upload-pack -- -foo.git But adding "--" automatically would make us inconsistent with a normal shell (i.e., when git-shell is not in use), where "-foo.git" would still be an error. For that case, the client would have to specify the "--", but they can't do so reliably, as existing versions of git-shell do not allow more than a single argument. The simplest thing is to simply disallow "-" at the start of the repo name argument. This hasn't worked either with or without git-shell since version 1.0.0, and nobody has complained. Note that this patch just applies to do_generic_cmd(), which runs upload-pack, receive-pack, and upload-archive. There are two other types of commands that git-shell runs: - do_cvs_cmd(), but this already restricts the argument to be the literal string "server" - admin-provided commands in the git-shell-commands directory. We'll pass along arbitrary arguments there, so these commands could have similar problems. But these commands might actually understand dashed arguments, so we cannot just block them here. It's up to the writer of the commands to make sure they are safe. With great power comes great responsibility. Reported-by: Timo Schmid <tschmid@ernw.de> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 7654286
abspath.c
#include "cache.h"
/*
* Do not use this for inspecting *tracked* content. When path is a
* symlink to a directory, we do not want to say it is a directory when
* dealing with tracked content in the working tree.
*/
int is_directory(const char *path)
{
struct stat st;
return (!stat(path, &st) && S_ISDIR(st.st_mode));
}
/* We allow "recursive" symbolic links. Only within reason, though. */
#define MAXDEPTH 5
/*
* Return the real path (i.e., absolute path, with symlinks resolved
* and extra slashes removed) equivalent to the specified path. (If
* you want an absolute path but don't mind links, use
* absolute_path().) The return value is a pointer to a static
* buffer.
*
* The input and all intermediate paths must be shorter than MAX_PATH.
* The directory part of path (i.e., everything up to the last
* dir_sep) must denote a valid, existing directory, but the last
* component need not exist. If die_on_error is set, then die with an
* informative error message if there is a problem. Otherwise, return
* NULL on errors (without generating any output).
*
* If path is our buffer, then return path, as it's already what the
* user wants.
*/
static const char *real_path_internal(const char *path, int die_on_error)
{
static struct strbuf sb = STRBUF_INIT;
char *retval = NULL;
/*
* If we have to temporarily chdir(), store the original CWD
* here so that we can chdir() back to it at the end of the
* function:
*/
struct strbuf cwd = STRBUF_INIT;
int depth = MAXDEPTH;
char *last_elem = NULL;
struct stat st;
/* We've already done it */
if (path == sb.buf)
return path;
if (!*path) {
if (die_on_error)
die("The empty string is not a valid path");
else
goto error_out;
}
strbuf_reset(&sb);
strbuf_addstr(&sb, path);
while (depth--) {
if (!is_directory(sb.buf)) {
char *last_slash = find_last_dir_sep(sb.buf);
if (last_slash) {
last_elem = xstrdup(last_slash + 1);
strbuf_setlen(&sb, last_slash - sb.buf + 1);
} else {
last_elem = xmemdupz(sb.buf, sb.len);
strbuf_reset(&sb);
}
}
if (sb.len) {
if (!cwd.len && strbuf_getcwd(&cwd)) {
if (die_on_error)
die_errno("Could not get current working directory");
else
goto error_out;
}
if (chdir(sb.buf)) {
if (die_on_error)
die_errno("Could not switch to '%s'",
sb.buf);
else
goto error_out;
}
}
if (strbuf_getcwd(&sb)) {
if (die_on_error)
die_errno("Could not get current working directory");
else
goto error_out;
}
if (last_elem) {
if (sb.len && !is_dir_sep(sb.buf[sb.len - 1]))
strbuf_addch(&sb, '/');
strbuf_addstr(&sb, last_elem);
free(last_elem);
last_elem = NULL;
}
if (!lstat(sb.buf, &st) && S_ISLNK(st.st_mode)) {
struct strbuf next_sb = STRBUF_INIT;
ssize_t len = strbuf_readlink(&next_sb, sb.buf, 0);
if (len < 0) {
if (die_on_error)
die_errno("Invalid symlink '%s'",
sb.buf);
else
goto error_out;
}
strbuf_swap(&sb, &next_sb);
strbuf_release(&next_sb);
} else
break;
}
retval = sb.buf;
error_out:
free(last_elem);
if (cwd.len && chdir(cwd.buf))
die_errno("Could not change back to '%s'", cwd.buf);
strbuf_release(&cwd);
return retval;
}
const char *real_path(const char *path)
{
return real_path_internal(path, 1);
}
const char *real_path_if_valid(const char *path)
{
return real_path_internal(path, 0);
}
/*
* Use this to get an absolute path from a relative one. If you want
* to resolve links, you should use real_path.
*/
const char *absolute_path(const char *path)
{
static struct strbuf sb = STRBUF_INIT;
strbuf_reset(&sb);
strbuf_add_absolute_path(&sb, path);
return sb.buf;
}
/*
* Unlike prefix_path, this should be used if the named file does
* not have to interact with index entry; i.e. name of a random file
* on the filesystem.
*/
const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
{
static struct strbuf path = STRBUF_INIT;
#ifndef GIT_WINDOWS_NATIVE
if (!pfx_len || is_absolute_path(arg))
return arg;
strbuf_reset(&path);
strbuf_add(&path, pfx, pfx_len);
strbuf_addstr(&path, arg);
#else
char *p;
/* don't add prefix to absolute paths, but still replace '\' by '/' */
strbuf_reset(&path);
if (is_absolute_path(arg))
pfx_len = 0;
else if (pfx_len)
strbuf_add(&path, pfx, pfx_len);
strbuf_addstr(&path, arg);
for (p = path.buf + pfx_len; *p; p++)
if (*p == '\\')
*p = '/';
#endif
return path.buf;
}
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