Revision 9cf85473209ea8ae2b56c13145c4704d12ee1374 authored by Filip Hejsek on 28 January 2024, 04:09:17 UTC, committed by Johannes Schindelin on 17 April 2024, 20:30:01 UTC
While it is expected to have several git dirs within the `.git/modules/` tree, it is important that they do not interfere with each other. For example, if one submodule was called "captain" and another submodule "captain/hooks", their respective git dirs would clash, as they would be located in `.git/modules/captain/` and `.git/modules/captain/hooks/`, respectively, i.e. the latter's files could clash with the actual Git hooks of the former. To prevent these clashes, and in particular to prevent hooks from being written and then executed as part of a recursive clone, we introduced checks as part of the fix for CVE-2019-1387 in a8dee3ca61 (Disallow dubiously-nested submodule git directories, 2019-10-01). It is currently possible to bypass the check for clashing submodule git dirs in two ways: 1. parallel cloning 2. checkout --recurse-submodules Let's check not only before, but also after parallel cloning (and before checking out the submodule), that the git dir is not clashing with another one, otherwise fail. This addresses the parallel cloning issue. As to the parallel checkout issue: It requires quite a few manual steps to create clashing git dirs because Git itself would refuse to initialize the inner one, as demonstrated by the test case. Nevertheless, let's teach the recursive checkout (namely, the `submodule_move_head()` function that is used by the recursive checkout) to be careful to verify that it does not use a clashing git dir, and if it does, disable it (by deleting the `HEAD` file so that subsequent Git calls won't recognize it as a git dir anymore). Note: The parallel cloning test case contains a `cat err` that proved to be highly useful when analyzing the racy nature of the operation (the operation can fail with three different error messages, depending on timing), and was left on purpose to ease future debugging should the need arise. Signed-off-by: Filip Hejsek <filip.hejsek@gmail.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
1 parent b20c10f
upload-archive.c
/*
* Copyright (c) 2006 Franck Bui-Huu
*/
#include "cache.h"
#include "builtin.h"
#include "archive.h"
#include "pkt-line.h"
#include "sideband.h"
#include "run-command.h"
#include "strvec.h"
static const char upload_archive_usage[] =
"git upload-archive <repository>";
static const char deadchild[] =
"git upload-archive: archiver died with error";
#define MAX_ARGS (64)
int cmd_upload_archive_writer(int argc, const char **argv, const char *prefix)
{
struct strvec sent_argv = STRVEC_INIT;
const char *arg_cmd = "argument ";
if (argc != 2 || !strcmp(argv[1], "-h"))
usage(upload_archive_usage);
if (!enter_repo(argv[1], 0))
die("'%s' does not appear to be a git repository", argv[1]);
init_archivers();
/* put received options in sent_argv[] */
strvec_push(&sent_argv, "git-upload-archive");
for (;;) {
char *buf = packet_read_line(0, NULL);
if (!buf)
break; /* got a flush */
if (sent_argv.nr > MAX_ARGS)
die("Too many options (>%d)", MAX_ARGS - 1);
if (!starts_with(buf, arg_cmd))
die("'argument' token or flush expected");
strvec_push(&sent_argv, buf + strlen(arg_cmd));
}
/* parse all options sent by the client */
return write_archive(sent_argv.nr, sent_argv.v, prefix,
the_repository, NULL, 1);
}
__attribute__((format (printf, 1, 2)))
static void error_clnt(const char *fmt, ...)
{
struct strbuf buf = STRBUF_INIT;
va_list params;
va_start(params, fmt);
strbuf_vaddf(&buf, fmt, params);
va_end(params);
send_sideband(1, 3, buf.buf, buf.len, LARGE_PACKET_MAX);
die("sent error to the client: %s", buf.buf);
}
static ssize_t process_input(int child_fd, int band)
{
char buf[16384];
ssize_t sz = read(child_fd, buf, sizeof(buf));
if (sz < 0) {
if (errno != EAGAIN && errno != EINTR)
error_clnt("read error: %s\n", strerror(errno));
return sz;
}
send_sideband(1, band, buf, sz, LARGE_PACKET_MAX);
return sz;
}
int cmd_upload_archive(int argc, const char **argv, const char *prefix)
{
struct child_process writer = CHILD_PROCESS_INIT;
if (argc == 2 && !strcmp(argv[1], "-h"))
usage(upload_archive_usage);
/*
* Set up sideband subprocess.
*
* We (parent) monitor and read from child, sending its fd#1 and fd#2
* multiplexed out to our fd#1. If the child dies, we tell the other
* end over channel #3.
*/
writer.out = writer.err = -1;
writer.git_cmd = 1;
strvec_push(&writer.args, "upload-archive--writer");
strvec_pushv(&writer.args, argv + 1);
if (start_command(&writer)) {
int err = errno;
packet_write_fmt(1, "NACK unable to spawn subprocess\n");
die("upload-archive: %s", strerror(err));
}
packet_write_fmt(1, "ACK\n");
packet_flush(1);
while (1) {
struct pollfd pfd[2];
pfd[0].fd = writer.out;
pfd[0].events = POLLIN;
pfd[1].fd = writer.err;
pfd[1].events = POLLIN;
if (poll(pfd, 2, -1) < 0) {
if (errno != EINTR) {
error_errno("poll failed resuming");
sleep(1);
}
continue;
}
if (pfd[1].revents & POLLIN)
/* Status stream ready */
if (process_input(pfd[1].fd, 2))
continue;
if (pfd[0].revents & POLLIN)
/* Data stream ready */
if (process_input(pfd[0].fd, 1))
continue;
if (finish_command(&writer))
error_clnt("%s", deadchild);
packet_flush(1);
break;
}
return 0;
}
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