git/http-backend.c
brian m. carlson f786ae9ff9 http-backend: allow 64-character hex names
In an SHA-256-backed repository using the http-backend handler for dumb
protocol clients, it may be necessary to access the raw packs using
their full SHA-256-specified names.  Allow packs and loose objects to be
accessed using their full SHA-256-specified 64-character hex names.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-01 11:57:38 +09:00

796 lines
19 KiB
C

#include "cache.h"
#include "config.h"
#include "repository.h"
#include "refs.h"
#include "pkt-line.h"
#include "object.h"
#include "tag.h"
#include "exec-cmd.h"
#include "run-command.h"
#include "string-list.h"
#include "url.h"
#include "argv-array.h"
#include "packfile.h"
#include "object-store.h"
#include "protocol.h"
static const char content_type[] = "Content-Type";
static const char content_length[] = "Content-Length";
static const char last_modified[] = "Last-Modified";
static int getanyfile = 1;
static unsigned long max_request_buffer = 10 * 1024 * 1024;
static struct string_list *query_params;
struct rpc_service {
const char *name;
const char *config_name;
unsigned buffer_input : 1;
signed enabled : 2;
};
static struct rpc_service rpc_service[] = {
{ "upload-pack", "uploadpack", 1, 1 },
{ "receive-pack", "receivepack", 0, -1 },
};
static struct string_list *get_parameters(void)
{
if (!query_params) {
const char *query = getenv("QUERY_STRING");
query_params = xcalloc(1, sizeof(*query_params));
while (query && *query) {
char *name = url_decode_parameter_name(&query);
char *value = url_decode_parameter_value(&query);
struct string_list_item *i;
i = string_list_lookup(query_params, name);
if (!i)
i = string_list_insert(query_params, name);
else
free(i->util);
i->util = value;
}
}
return query_params;
}
static const char *get_parameter(const char *name)
{
struct string_list_item *i;
i = string_list_lookup(get_parameters(), name);
return i ? i->util : NULL;
}
__attribute__((format (printf, 2, 3)))
static void format_write(int fd, const char *fmt, ...)
{
static char buffer[1024];
va_list args;
unsigned n;
va_start(args, fmt);
n = vsnprintf(buffer, sizeof(buffer), fmt, args);
va_end(args);
if (n >= sizeof(buffer))
die("protocol error: impossibly long line");
write_or_die(fd, buffer, n);
}
static void http_status(struct strbuf *hdr, unsigned code, const char *msg)
{
strbuf_addf(hdr, "Status: %u %s\r\n", code, msg);
}
static void hdr_str(struct strbuf *hdr, const char *name, const char *value)
{
strbuf_addf(hdr, "%s: %s\r\n", name, value);
}
static void hdr_int(struct strbuf *hdr, const char *name, uintmax_t value)
{
strbuf_addf(hdr, "%s: %" PRIuMAX "\r\n", name, value);
}
static void hdr_date(struct strbuf *hdr, const char *name, timestamp_t when)
{
const char *value = show_date(when, 0, DATE_MODE(RFC2822));
hdr_str(hdr, name, value);
}
static void hdr_nocache(struct strbuf *hdr)
{
hdr_str(hdr, "Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
hdr_str(hdr, "Pragma", "no-cache");
hdr_str(hdr, "Cache-Control", "no-cache, max-age=0, must-revalidate");
}
static void hdr_cache_forever(struct strbuf *hdr)
{
timestamp_t now = time(NULL);
hdr_date(hdr, "Date", now);
hdr_date(hdr, "Expires", now + 31536000);
hdr_str(hdr, "Cache-Control", "public, max-age=31536000");
}
static void end_headers(struct strbuf *hdr)
{
strbuf_add(hdr, "\r\n", 2);
write_or_die(1, hdr->buf, hdr->len);
strbuf_release(hdr);
}
__attribute__((format (printf, 2, 3)))
static NORETURN void not_found(struct strbuf *hdr, const char *err, ...)
{
va_list params;
http_status(hdr, 404, "Not Found");
hdr_nocache(hdr);
end_headers(hdr);
va_start(params, err);
if (err && *err)
vfprintf(stderr, err, params);
va_end(params);
exit(0);
}
__attribute__((format (printf, 2, 3)))
static NORETURN void forbidden(struct strbuf *hdr, const char *err, ...)
{
va_list params;
http_status(hdr, 403, "Forbidden");
hdr_nocache(hdr);
end_headers(hdr);
va_start(params, err);
if (err && *err)
vfprintf(stderr, err, params);
va_end(params);
exit(0);
}
static void select_getanyfile(struct strbuf *hdr)
{
if (!getanyfile)
forbidden(hdr, "Unsupported service: getanyfile");
}
static void send_strbuf(struct strbuf *hdr,
const char *type, struct strbuf *buf)
{
hdr_int(hdr, content_length, buf->len);
hdr_str(hdr, content_type, type);
end_headers(hdr);
write_or_die(1, buf->buf, buf->len);
}
static void send_local_file(struct strbuf *hdr, const char *the_type,
const char *name)
{
char *p = git_pathdup("%s", name);
size_t buf_alloc = 8192;
char *buf = xmalloc(buf_alloc);
int fd;
struct stat sb;
fd = open(p, O_RDONLY);
if (fd < 0)
not_found(hdr, "Cannot open '%s': %s", p, strerror(errno));
if (fstat(fd, &sb) < 0)
die_errno("Cannot stat '%s'", p);
hdr_int(hdr, content_length, sb.st_size);
hdr_str(hdr, content_type, the_type);
hdr_date(hdr, last_modified, sb.st_mtime);
end_headers(hdr);
for (;;) {
ssize_t n = xread(fd, buf, buf_alloc);
if (n < 0)
die_errno("Cannot read '%s'", p);
if (!n)
break;
write_or_die(1, buf, n);
}
close(fd);
free(buf);
free(p);
}
static void get_text_file(struct strbuf *hdr, char *name)
{
select_getanyfile(hdr);
hdr_nocache(hdr);
send_local_file(hdr, "text/plain", name);
}
static void get_loose_object(struct strbuf *hdr, char *name)
{
select_getanyfile(hdr);
hdr_cache_forever(hdr);
send_local_file(hdr, "application/x-git-loose-object", name);
}
static void get_pack_file(struct strbuf *hdr, char *name)
{
select_getanyfile(hdr);
hdr_cache_forever(hdr);
send_local_file(hdr, "application/x-git-packed-objects", name);
}
static void get_idx_file(struct strbuf *hdr, char *name)
{
select_getanyfile(hdr);
hdr_cache_forever(hdr);
send_local_file(hdr, "application/x-git-packed-objects-toc", name);
}
static void http_config(void)
{
int i, value = 0;
struct strbuf var = STRBUF_INIT;
git_config_get_bool("http.getanyfile", &getanyfile);
git_config_get_ulong("http.maxrequestbuffer", &max_request_buffer);
for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
struct rpc_service *svc = &rpc_service[i];
strbuf_addf(&var, "http.%s", svc->config_name);
if (!git_config_get_bool(var.buf, &value))
svc->enabled = value;
strbuf_reset(&var);
}
strbuf_release(&var);
}
static struct rpc_service *select_service(struct strbuf *hdr, const char *name)
{
const char *svc_name;
struct rpc_service *svc = NULL;
int i;
if (!skip_prefix(name, "git-", &svc_name))
forbidden(hdr, "Unsupported service: '%s'", name);
for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
struct rpc_service *s = &rpc_service[i];
if (!strcmp(s->name, svc_name)) {
svc = s;
break;
}
}
if (!svc)
forbidden(hdr, "Unsupported service: '%s'", name);
if (svc->enabled < 0) {
const char *user = getenv("REMOTE_USER");
svc->enabled = (user && *user) ? 1 : 0;
}
if (!svc->enabled)
forbidden(hdr, "Service not enabled: '%s'", svc->name);
return svc;
}
static void write_to_child(int out, const unsigned char *buf, ssize_t len, const char *prog_name)
{
if (write_in_full(out, buf, len) < 0)
die("unable to write to '%s'", prog_name);
}
/*
* This is basically strbuf_read(), except that if we
* hit max_request_buffer we die (we'd rather reject a
* maliciously large request than chew up infinite memory).
*/
static ssize_t read_request_eof(int fd, unsigned char **out)
{
size_t len = 0, alloc = 8192;
unsigned char *buf = xmalloc(alloc);
if (max_request_buffer < alloc)
max_request_buffer = alloc;
while (1) {
ssize_t cnt;
cnt = read_in_full(fd, buf + len, alloc - len);
if (cnt < 0) {
free(buf);
return -1;
}
/* partial read from read_in_full means we hit EOF */
len += cnt;
if (len < alloc) {
*out = buf;
return len;
}
/* otherwise, grow and try again (if we can) */
if (alloc == max_request_buffer)
die("request was larger than our maximum size (%lu);"
" try setting GIT_HTTP_MAX_REQUEST_BUFFER",
max_request_buffer);
alloc = alloc_nr(alloc);
if (alloc > max_request_buffer)
alloc = max_request_buffer;
REALLOC_ARRAY(buf, alloc);
}
}
static ssize_t read_request_fixed_len(int fd, ssize_t req_len, unsigned char **out)
{
unsigned char *buf = NULL;
ssize_t cnt = 0;
if (max_request_buffer < req_len) {
die("request was larger than our maximum size (%lu): "
"%" PRIuMAX "; try setting GIT_HTTP_MAX_REQUEST_BUFFER",
max_request_buffer, (uintmax_t)req_len);
}
buf = xmalloc(req_len);
cnt = read_in_full(fd, buf, req_len);
if (cnt < 0) {
free(buf);
return -1;
}
*out = buf;
return cnt;
}
static ssize_t get_content_length(void)
{
ssize_t val = -1;
const char *str = getenv("CONTENT_LENGTH");
if (str && *str && !git_parse_ssize_t(str, &val))
die("failed to parse CONTENT_LENGTH: %s", str);
return val;
}
static ssize_t read_request(int fd, unsigned char **out, ssize_t req_len)
{
if (req_len < 0)
return read_request_eof(fd, out);
else
return read_request_fixed_len(fd, req_len, out);
}
static void inflate_request(const char *prog_name, int out, int buffer_input, ssize_t req_len)
{
git_zstream stream;
unsigned char *full_request = NULL;
unsigned char in_buf[8192];
unsigned char out_buf[8192];
unsigned long cnt = 0;
int req_len_defined = req_len >= 0;
size_t req_remaining_len = req_len;
memset(&stream, 0, sizeof(stream));
git_inflate_init_gzip_only(&stream);
while (1) {
ssize_t n;
if (buffer_input) {
if (full_request)
n = 0; /* nothing left to read */
else
n = read_request(0, &full_request, req_len);
stream.next_in = full_request;
} else {
ssize_t buffer_len;
if (req_len_defined && req_remaining_len <= sizeof(in_buf))
buffer_len = req_remaining_len;
else
buffer_len = sizeof(in_buf);
n = xread(0, in_buf, buffer_len);
stream.next_in = in_buf;
if (req_len_defined && n > 0)
req_remaining_len -= n;
}
if (n <= 0)
die("request ended in the middle of the gzip stream");
stream.avail_in = n;
while (0 < stream.avail_in) {
int ret;
stream.next_out = out_buf;
stream.avail_out = sizeof(out_buf);
ret = git_inflate(&stream, Z_NO_FLUSH);
if (ret != Z_OK && ret != Z_STREAM_END)
die("zlib error inflating request, result %d", ret);
n = stream.total_out - cnt;
write_to_child(out, out_buf, stream.total_out - cnt, prog_name);
cnt = stream.total_out;
if (ret == Z_STREAM_END)
goto done;
}
}
done:
git_inflate_end(&stream);
close(out);
free(full_request);
}
static void copy_request(const char *prog_name, int out, ssize_t req_len)
{
unsigned char *buf;
ssize_t n = read_request(0, &buf, req_len);
if (n < 0)
die_errno("error reading request body");
write_to_child(out, buf, n, prog_name);
close(out);
free(buf);
}
static void pipe_fixed_length(const char *prog_name, int out, size_t req_len)
{
unsigned char buf[8192];
size_t remaining_len = req_len;
while (remaining_len > 0) {
size_t chunk_length = remaining_len > sizeof(buf) ? sizeof(buf) : remaining_len;
ssize_t n = xread(0, buf, chunk_length);
if (n < 0)
die_errno("Reading request failed");
write_to_child(out, buf, n, prog_name);
remaining_len -= n;
}
close(out);
}
static void run_service(const char **argv, int buffer_input)
{
const char *encoding = getenv("HTTP_CONTENT_ENCODING");
const char *user = getenv("REMOTE_USER");
const char *host = getenv("REMOTE_ADDR");
int gzipped_request = 0;
struct child_process cld = CHILD_PROCESS_INIT;
ssize_t req_len = get_content_length();
if (encoding && !strcmp(encoding, "gzip"))
gzipped_request = 1;
else if (encoding && !strcmp(encoding, "x-gzip"))
gzipped_request = 1;
if (!user || !*user)
user = "anonymous";
if (!host || !*host)
host = "(none)";
if (!getenv("GIT_COMMITTER_NAME"))
argv_array_pushf(&cld.env_array, "GIT_COMMITTER_NAME=%s", user);
if (!getenv("GIT_COMMITTER_EMAIL"))
argv_array_pushf(&cld.env_array,
"GIT_COMMITTER_EMAIL=%s@http.%s", user, host);
cld.argv = argv;
if (buffer_input || gzipped_request || req_len >= 0)
cld.in = -1;
cld.git_cmd = 1;
cld.clean_on_exit = 1;
cld.wait_after_clean = 1;
if (start_command(&cld))
exit(1);
close(1);
if (gzipped_request)
inflate_request(argv[0], cld.in, buffer_input, req_len);
else if (buffer_input)
copy_request(argv[0], cld.in, req_len);
else if (req_len >= 0)
pipe_fixed_length(argv[0], cld.in, req_len);
else
close(0);
if (finish_command(&cld))
exit(1);
}
static int show_text_ref(const char *name, const struct object_id *oid,
int flag, void *cb_data)
{
const char *name_nons = strip_namespace(name);
struct strbuf *buf = cb_data;
struct object *o = parse_object(the_repository, oid);
if (!o)
return 0;
strbuf_addf(buf, "%s\t%s\n", oid_to_hex(oid), name_nons);
if (o->type == OBJ_TAG) {
o = deref_tag(the_repository, o, name, 0);
if (!o)
return 0;
strbuf_addf(buf, "%s\t%s^{}\n", oid_to_hex(&o->oid),
name_nons);
}
return 0;
}
static void get_info_refs(struct strbuf *hdr, char *arg)
{
const char *service_name = get_parameter("service");
struct strbuf buf = STRBUF_INIT;
hdr_nocache(hdr);
if (service_name) {
const char *argv[] = {NULL /* service name */,
"--stateless-rpc", "--advertise-refs",
".", NULL};
struct rpc_service *svc = select_service(hdr, service_name);
strbuf_addf(&buf, "application/x-git-%s-advertisement",
svc->name);
hdr_str(hdr, content_type, buf.buf);
end_headers(hdr);
if (determine_protocol_version_server() != protocol_v2) {
packet_write_fmt(1, "# service=git-%s\n", svc->name);
packet_flush(1);
}
argv[0] = svc->name;
run_service(argv, 0);
} else {
select_getanyfile(hdr);
for_each_namespaced_ref(show_text_ref, &buf);
send_strbuf(hdr, "text/plain", &buf);
}
strbuf_release(&buf);
}
static int show_head_ref(const char *refname, const struct object_id *oid,
int flag, void *cb_data)
{
struct strbuf *buf = cb_data;
if (flag & REF_ISSYMREF) {
const char *target = resolve_ref_unsafe(refname,
RESOLVE_REF_READING,
NULL, NULL);
if (target)
strbuf_addf(buf, "ref: %s\n", strip_namespace(target));
} else {
strbuf_addf(buf, "%s\n", oid_to_hex(oid));
}
return 0;
}
static void get_head(struct strbuf *hdr, char *arg)
{
struct strbuf buf = STRBUF_INIT;
select_getanyfile(hdr);
head_ref_namespaced(show_head_ref, &buf);
send_strbuf(hdr, "text/plain", &buf);
strbuf_release(&buf);
}
static void get_info_packs(struct strbuf *hdr, char *arg)
{
size_t objdirlen = strlen(get_object_directory());
struct strbuf buf = STRBUF_INIT;
struct packed_git *p;
size_t cnt = 0;
select_getanyfile(hdr);
for (p = get_all_packs(the_repository); p; p = p->next) {
if (p->pack_local)
cnt++;
}
strbuf_grow(&buf, cnt * 53 + 2);
for (p = get_all_packs(the_repository); p; p = p->next) {
if (p->pack_local)
strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
}
strbuf_addch(&buf, '\n');
hdr_nocache(hdr);
send_strbuf(hdr, "text/plain; charset=utf-8", &buf);
strbuf_release(&buf);
}
static void check_content_type(struct strbuf *hdr, const char *accepted_type)
{
const char *actual_type = getenv("CONTENT_TYPE");
if (!actual_type)
actual_type = "";
if (strcmp(actual_type, accepted_type)) {
http_status(hdr, 415, "Unsupported Media Type");
hdr_nocache(hdr);
end_headers(hdr);
format_write(1,
"Expected POST with Content-Type '%s',"
" but received '%s' instead.\n",
accepted_type, actual_type);
exit(0);
}
}
static void service_rpc(struct strbuf *hdr, char *service_name)
{
const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
struct rpc_service *svc = select_service(hdr, service_name);
struct strbuf buf = STRBUF_INIT;
strbuf_reset(&buf);
strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
check_content_type(hdr, buf.buf);
hdr_nocache(hdr);
strbuf_reset(&buf);
strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
hdr_str(hdr, content_type, buf.buf);
end_headers(hdr);
argv[0] = svc->name;
run_service(argv, svc->buffer_input);
strbuf_release(&buf);
}
static int dead;
static NORETURN void die_webcgi(const char *err, va_list params)
{
if (dead <= 1) {
struct strbuf hdr = STRBUF_INIT;
vreportf("fatal: ", err, params);
http_status(&hdr, 500, "Internal Server Error");
hdr_nocache(&hdr);
end_headers(&hdr);
}
exit(0); /* we successfully reported a failure ;-) */
}
static int die_webcgi_recursing(void)
{
return dead++ > 1;
}
static char* getdir(void)
{
struct strbuf buf = STRBUF_INIT;
char *pathinfo = getenv("PATH_INFO");
char *root = getenv("GIT_PROJECT_ROOT");
char *path = getenv("PATH_TRANSLATED");
if (root && *root) {
if (!pathinfo || !*pathinfo)
die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
if (daemon_avoid_alias(pathinfo))
die("'%s': aliased", pathinfo);
end_url_with_slash(&buf, root);
if (pathinfo[0] == '/')
pathinfo++;
strbuf_addstr(&buf, pathinfo);
return strbuf_detach(&buf, NULL);
} else if (path && *path) {
return xstrdup(path);
} else
die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
return NULL;
}
static struct service_cmd {
const char *method;
const char *pattern;
void (*imp)(struct strbuf *, char *);
} services[] = {
{"GET", "/HEAD$", get_head},
{"GET", "/info/refs$", get_info_refs},
{"GET", "/objects/info/alternates$", get_text_file},
{"GET", "/objects/info/http-alternates$", get_text_file},
{"GET", "/objects/info/packs$", get_info_packs},
{"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
{"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{62}$", get_loose_object},
{"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
{"GET", "/objects/pack/pack-[0-9a-f]{64}\\.pack$", get_pack_file},
{"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
{"GET", "/objects/pack/pack-[0-9a-f]{64}\\.idx$", get_idx_file},
{"POST", "/git-upload-pack$", service_rpc},
{"POST", "/git-receive-pack$", service_rpc}
};
static int bad_request(struct strbuf *hdr, const struct service_cmd *c)
{
const char *proto = getenv("SERVER_PROTOCOL");
if (proto && !strcmp(proto, "HTTP/1.1")) {
http_status(hdr, 405, "Method Not Allowed");
hdr_str(hdr, "Allow",
!strcmp(c->method, "GET") ? "GET, HEAD" : c->method);
} else
http_status(hdr, 400, "Bad Request");
hdr_nocache(hdr);
end_headers(hdr);
return 0;
}
int cmd_main(int argc, const char **argv)
{
char *method = getenv("REQUEST_METHOD");
char *dir;
struct service_cmd *cmd = NULL;
char *cmd_arg = NULL;
int i;
struct strbuf hdr = STRBUF_INIT;
set_die_routine(die_webcgi);
set_die_is_recursing_routine(die_webcgi_recursing);
if (!method)
die("No REQUEST_METHOD from server");
if (!strcmp(method, "HEAD"))
method = "GET";
dir = getdir();
for (i = 0; i < ARRAY_SIZE(services); i++) {
struct service_cmd *c = &services[i];
regex_t re;
regmatch_t out[1];
if (regcomp(&re, c->pattern, REG_EXTENDED))
die("Bogus regex in service table: %s", c->pattern);
if (!regexec(&re, dir, 1, out, 0)) {
size_t n;
if (strcmp(method, c->method))
return bad_request(&hdr, c);
cmd = c;
n = out[0].rm_eo - out[0].rm_so;
cmd_arg = xmemdupz(dir + out[0].rm_so + 1, n - 1);
dir[out[0].rm_so] = 0;
break;
}
regfree(&re);
}
if (!cmd)
not_found(&hdr, "Request not supported: '%s'", dir);
setup_path();
if (!enter_repo(dir, 0))
not_found(&hdr, "Not a git repository: '%s'", dir);
if (!getenv("GIT_HTTP_EXPORT_ALL") &&
access("git-daemon-export-ok", F_OK) )
not_found(&hdr, "Repository not exported: '%s'", dir);
http_config();
max_request_buffer = git_env_ulong("GIT_HTTP_MAX_REQUEST_BUFFER",
max_request_buffer);
cmd->imp(&hdr, cmd_arg);
return 0;
}