Revision 24036686c4af84c9e84e486ef3debab6e6d8e6b5 authored by Jeff King on 19 April 2020, 03:48:05 UTC, committed by Jonathan Nieder on 19 April 2020, 23:10:57 UTC
We may feed a URL like "cert:///path/to/cert.pem" into the credential
machinery to get the key for a client-side certificate. That
credential has no hostname field, which is about to be disallowed (to
avoid confusion with protocols where a helper _would_ expect a
hostname).

This means as of the next patch, credential helpers won't work for
unlocking certs. Let's fix that by doing two things:

  - when we parse a url with an empty host, set the host field to the
    empty string (asking only to match stored entries with an empty
    host) rather than NULL (asking to match _any_ host).

  - when we build a cert:// credential by hand, similarly assign an
    empty string

It's the latter that is more likely to impact real users in practice,
since it's what's used for http connections. But we don't have good
infrastructure to test it.

The url-parsing version will help anybody using git-credential in a
script, and is easy to test.

Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
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Raw File
zlib.c
/*
 * zlib wrappers to make sure we don't silently miss errors
 * at init time.
 */
#include "cache.h"

static const char *zerr_to_string(int status)
{
	switch (status) {
	case Z_MEM_ERROR:
		return "out of memory";
	case Z_VERSION_ERROR:
		return "wrong version";
	case Z_NEED_DICT:
		return "needs dictionary";
	case Z_DATA_ERROR:
		return "data stream error";
	case Z_STREAM_ERROR:
		return "stream consistency error";
	default:
		return "unknown error";
	}
}

/*
 * avail_in and avail_out in zlib are counted in uInt, which typically
 * limits the size of the buffer we can use to 4GB when interacting
 * with zlib in a single call to inflate/deflate.
 */
/* #define ZLIB_BUF_MAX ((uInt)-1) */
#define ZLIB_BUF_MAX ((uInt) 1024 * 1024 * 1024) /* 1GB */
static inline uInt zlib_buf_cap(unsigned long len)
{
	return (ZLIB_BUF_MAX < len) ? ZLIB_BUF_MAX : len;
}

static void zlib_pre_call(git_zstream *s)
{
	s->z.next_in = s->next_in;
	s->z.next_out = s->next_out;
	s->z.total_in = s->total_in;
	s->z.total_out = s->total_out;
	s->z.avail_in = zlib_buf_cap(s->avail_in);
	s->z.avail_out = zlib_buf_cap(s->avail_out);
}

static void zlib_post_call(git_zstream *s)
{
	unsigned long bytes_consumed;
	unsigned long bytes_produced;

	bytes_consumed = s->z.next_in - s->next_in;
	bytes_produced = s->z.next_out - s->next_out;
	if (s->z.total_out != s->total_out + bytes_produced)
		die("BUG: total_out mismatch");
	if (s->z.total_in != s->total_in + bytes_consumed)
		die("BUG: total_in mismatch");

	s->total_out = s->z.total_out;
	s->total_in = s->z.total_in;
	s->next_in = s->z.next_in;
	s->next_out = s->z.next_out;
	s->avail_in -= bytes_consumed;
	s->avail_out -= bytes_produced;
}

void git_inflate_init(git_zstream *strm)
{
	int status;

	zlib_pre_call(strm);
	status = inflateInit(&strm->z);
	zlib_post_call(strm);
	if (status == Z_OK)
		return;
	die("inflateInit: %s (%s)", zerr_to_string(status),
	    strm->z.msg ? strm->z.msg : "no message");
}

void git_inflate_init_gzip_only(git_zstream *strm)
{
	/*
	 * Use default 15 bits, +16 is to accept only gzip and to
	 * yield Z_DATA_ERROR when fed zlib format.
	 */
	const int windowBits = 15 + 16;
	int status;

	zlib_pre_call(strm);
	status = inflateInit2(&strm->z, windowBits);
	zlib_post_call(strm);
	if (status == Z_OK)
		return;
	die("inflateInit2: %s (%s)", zerr_to_string(status),
	    strm->z.msg ? strm->z.msg : "no message");
}

void git_inflate_end(git_zstream *strm)
{
	int status;

	zlib_pre_call(strm);
	status = inflateEnd(&strm->z);
	zlib_post_call(strm);
	if (status == Z_OK)
		return;
	error("inflateEnd: %s (%s)", zerr_to_string(status),
	      strm->z.msg ? strm->z.msg : "no message");
}

int git_inflate(git_zstream *strm, int flush)
{
	int status;

	for (;;) {
		zlib_pre_call(strm);
		/* Never say Z_FINISH unless we are feeding everything */
		status = inflate(&strm->z,
				 (strm->z.avail_in != strm->avail_in)
				 ? 0 : flush);
		if (status == Z_MEM_ERROR)
			die("inflate: out of memory");
		zlib_post_call(strm);

		/*
		 * Let zlib work another round, while we can still
		 * make progress.
		 */
		if ((strm->avail_out && !strm->z.avail_out) &&
		    (status == Z_OK || status == Z_BUF_ERROR))
			continue;
		break;
	}

	switch (status) {
	/* Z_BUF_ERROR: normal, needs more space in the output buffer */
	case Z_BUF_ERROR:
	case Z_OK:
	case Z_STREAM_END:
		return status;
	default:
		break;
	}
	error("inflate: %s (%s)", zerr_to_string(status),
	      strm->z.msg ? strm->z.msg : "no message");
	return status;
}

#if defined(NO_DEFLATE_BOUND) || ZLIB_VERNUM < 0x1200
#define deflateBound(c,s)  ((s) + (((s) + 7) >> 3) + (((s) + 63) >> 6) + 11)
#endif

unsigned long git_deflate_bound(git_zstream *strm, unsigned long size)
{
	return deflateBound(&strm->z, size);
}

void git_deflate_init(git_zstream *strm, int level)
{
	int status;

	memset(strm, 0, sizeof(*strm));
	zlib_pre_call(strm);
	status = deflateInit(&strm->z, level);
	zlib_post_call(strm);
	if (status == Z_OK)
		return;
	die("deflateInit: %s (%s)", zerr_to_string(status),
	    strm->z.msg ? strm->z.msg : "no message");
}

static void do_git_deflate_init(git_zstream *strm, int level, int windowBits)
{
	int status;

	memset(strm, 0, sizeof(*strm));
	zlib_pre_call(strm);
	status = deflateInit2(&strm->z, level,
				  Z_DEFLATED, windowBits,
				  8, Z_DEFAULT_STRATEGY);
	zlib_post_call(strm);
	if (status == Z_OK)
		return;
	die("deflateInit2: %s (%s)", zerr_to_string(status),
	    strm->z.msg ? strm->z.msg : "no message");
}

void git_deflate_init_gzip(git_zstream *strm, int level)
{
	/*
	 * Use default 15 bits, +16 is to generate gzip header/trailer
	 * instead of the zlib wrapper.
	 */
	do_git_deflate_init(strm, level, 15 + 16);
}

void git_deflate_init_raw(git_zstream *strm, int level)
{
	/*
	 * Use default 15 bits, negate the value to get raw compressed
	 * data without zlib header and trailer.
	 */
	do_git_deflate_init(strm, level, -15);
}

int git_deflate_abort(git_zstream *strm)
{
	int status;

	zlib_pre_call(strm);
	status = deflateEnd(&strm->z);
	zlib_post_call(strm);
	return status;
}

void git_deflate_end(git_zstream *strm)
{
	int status = git_deflate_abort(strm);

	if (status == Z_OK)
		return;
	error("deflateEnd: %s (%s)", zerr_to_string(status),
	      strm->z.msg ? strm->z.msg : "no message");
}

int git_deflate_end_gently(git_zstream *strm)
{
	int status;

	zlib_pre_call(strm);
	status = deflateEnd(&strm->z);
	zlib_post_call(strm);
	return status;
}

int git_deflate(git_zstream *strm, int flush)
{
	int status;

	for (;;) {
		zlib_pre_call(strm);

		/* Never say Z_FINISH unless we are feeding everything */
		status = deflate(&strm->z,
				 (strm->z.avail_in != strm->avail_in)
				 ? 0 : flush);
		if (status == Z_MEM_ERROR)
			die("deflate: out of memory");
		zlib_post_call(strm);

		/*
		 * Let zlib work another round, while we can still
		 * make progress.
		 */
		if ((strm->avail_out && !strm->z.avail_out) &&
		    (status == Z_OK || status == Z_BUF_ERROR))
			continue;
		break;
	}

	switch (status) {
	/* Z_BUF_ERROR: normal, needs more space in the output buffer */
	case Z_BUF_ERROR:
	case Z_OK:
	case Z_STREAM_END:
		return status;
	default:
		break;
	}
	error("deflate: %s (%s)", zerr_to_string(status),
	      strm->z.msg ? strm->z.msg : "no message");
	return status;
}
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