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
show-index.c
#include "cache.h"
#include "pack.h"
static const char show_index_usage[] =
"git show-index < <packed archive index>";
int main(int argc, char **argv)
{
int i;
unsigned nr;
unsigned int version;
static unsigned int top_index[256];
git_setup_gettext();
if (argc != 1)
usage(show_index_usage);
if (fread(top_index, 2 * 4, 1, stdin) != 1)
die("unable to read header");
if (top_index[0] == htonl(PACK_IDX_SIGNATURE)) {
version = ntohl(top_index[1]);
if (version < 2 || version > 2)
die("unknown index version");
if (fread(top_index, 256 * 4, 1, stdin) != 1)
die("unable to read index");
} else {
version = 1;
if (fread(&top_index[2], 254 * 4, 1, stdin) != 1)
die("unable to read index");
}
nr = 0;
for (i = 0; i < 256; i++) {
unsigned n = ntohl(top_index[i]);
if (n < nr)
die("corrupt index file");
nr = n;
}
if (version == 1) {
for (i = 0; i < nr; i++) {
unsigned int offset, entry[6];
if (fread(entry, 4 + 20, 1, stdin) != 1)
die("unable to read entry %u/%u", i, nr);
offset = ntohl(entry[0]);
printf("%u %s\n", offset, sha1_to_hex((void *)(entry+1)));
}
} else {
unsigned off64_nr = 0;
struct {
unsigned char sha1[20];
uint32_t crc;
uint32_t off;
} *entries = xmalloc(nr * sizeof(entries[0]));
for (i = 0; i < nr; i++)
if (fread(entries[i].sha1, 20, 1, stdin) != 1)
die("unable to read sha1 %u/%u", i, nr);
for (i = 0; i < nr; i++)
if (fread(&entries[i].crc, 4, 1, stdin) != 1)
die("unable to read crc %u/%u", i, nr);
for (i = 0; i < nr; i++)
if (fread(&entries[i].off, 4, 1, stdin) != 1)
die("unable to read 32b offset %u/%u", i, nr);
for (i = 0; i < nr; i++) {
uint64_t offset;
uint32_t off = ntohl(entries[i].off);
if (!(off & 0x80000000)) {
offset = off;
} else {
uint32_t off64[2];
if ((off & 0x7fffffff) != off64_nr)
die("inconsistent 64b offset index");
if (fread(off64, 8, 1, stdin) != 1)
die("unable to read 64b offset %u", off64_nr);
offset = (((uint64_t)ntohl(off64[0])) << 32) |
ntohl(off64[1]);
off64_nr++;
}
printf("%" PRIuMAX " %s (%08"PRIx32")\n",
(uintmax_t) offset,
sha1_to_hex(entries[i].sha1),
ntohl(entries[i].crc));
}
free(entries);
}
return 0;
}
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