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
url.c
#include "cache.h"
#include "url.h"
int is_urlschemechar(int first_flag, int ch)
{
/*
* The set of valid URL schemes, as per STD66 (RFC3986) is
* '[A-Za-z][A-Za-z0-9+.-]*'. But use sightly looser check
* of '[A-Za-z0-9][A-Za-z0-9+.-]*' because earlier version
* of check used '[A-Za-z0-9]+' so not to break any remote
* helpers.
*/
int alphanumeric, special;
alphanumeric = ch > 0 && isalnum(ch);
special = ch == '+' || ch == '-' || ch == '.';
return alphanumeric || (!first_flag && special);
}
int is_url(const char *url)
{
/* Is "scheme" part reasonable? */
if (!url || !is_urlschemechar(1, *url++))
return 0;
while (*url && *url != ':') {
if (!is_urlschemechar(0, *url++))
return 0;
}
/* We've seen "scheme"; we want colon-slash-slash */
return (url[0] == ':' && url[1] == '/' && url[2] == '/');
}
static int url_decode_char(const char *q)
{
int i;
unsigned char val = 0;
for (i = 0; i < 2; i++) {
unsigned char c = *q++;
val <<= 4;
if (c >= '0' && c <= '9')
val += c - '0';
else if (c >= 'a' && c <= 'f')
val += c - 'a' + 10;
else if (c >= 'A' && c <= 'F')
val += c - 'A' + 10;
else
return -1;
}
return val;
}
static char *url_decode_internal(const char **query, int len,
const char *stop_at, struct strbuf *out,
int decode_plus)
{
const char *q = *query;
while (len) {
unsigned char c = *q;
if (!c)
break;
if (stop_at && strchr(stop_at, c)) {
q++;
len--;
break;
}
if (c == '%') {
int val = url_decode_char(q + 1);
if (0 <= val) {
strbuf_addch(out, val);
q += 3;
len -= 3;
continue;
}
}
if (decode_plus && c == '+')
strbuf_addch(out, ' ');
else
strbuf_addch(out, c);
q++;
len--;
}
*query = q;
return strbuf_detach(out, NULL);
}
char *url_decode(const char *url)
{
return url_decode_mem(url, strlen(url));
}
char *url_decode_mem(const char *url, int len)
{
struct strbuf out = STRBUF_INIT;
const char *colon = memchr(url, ':', len);
/* Skip protocol part if present */
if (colon && url < colon) {
strbuf_add(&out, url, colon - url);
len -= colon - url;
url = colon;
}
return url_decode_internal(&url, len, NULL, &out, 0);
}
char *url_decode_parameter_name(const char **query)
{
struct strbuf out = STRBUF_INIT;
return url_decode_internal(query, -1, "&=", &out, 1);
}
char *url_decode_parameter_value(const char **query)
{
struct strbuf out = STRBUF_INIT;
return url_decode_internal(query, -1, "&", &out, 1);
}
void end_url_with_slash(struct strbuf *buf, const char *url)
{
strbuf_addstr(buf, url);
if (buf->len && buf->buf[buf->len - 1] != '/')
strbuf_addch(buf, '/');
}
void str_end_url_with_slash(const char *url, char **dest) {
struct strbuf buf = STRBUF_INIT;
end_url_with_slash(&buf, url);
free(*dest);
*dest = strbuf_detach(&buf, NULL);
}
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