thodg/libgit2/src/diff_print.c

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• Hash : 1e4976cb
  Author :
  Date : 2014-05-08T10:17:14
  

  Be more careful with user-supplied buffers This adds in missing calls to `git_buf_sanitize` and fixes a number of places where `git_buf` APIs could inadvertently write NUL terminator bytes into invalid buffers. This also changes the behavior of `git_buf_sanitize` to NUL terminate a buffer if it can and of `git_buf_shorten` to do nothing if it can. Adds tests of filtering code with zeroed (i.e. unsanitized) buffer which was previously triggering a segfault.

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• src/diff_print.c

• /*
   * Copyright (C) the libgit2 contributors. All rights reserved.
   *
   * This file is part of libgit2, distributed under the GNU GPL v2 with
   * a Linking Exception. For full terms see the included COPYING file.
   */
  #include "common.h"
  #include "diff.h"
  #include "diff_patch.h"
  #include "fileops.h"
  #include "zstream.h"
  #include "blob.h"
  #include "delta.h"
  #include "git2/sys/diff.h"
  
  typedef struct {
  	git_diff *diff;
  	git_diff_format_t format;
  	git_diff_line_cb print_cb;
  	void *payload;
  	git_buf *buf;
  	uint32_t flags;
  	int oid_strlen;
  	git_diff_line line;
  } diff_print_info;
  
  static int diff_print_info_init(
  	diff_print_info *pi,
  	git_buf *out,
  	git_diff *diff,
  	git_diff_format_t format,
  	git_diff_line_cb cb,
  	void *payload)
  {
  	pi->diff     = diff;
  	pi->format   = format;
  	pi->print_cb = cb;
  	pi->payload  = payload;
  	pi->buf      = out;
  
  	if (diff)
  		pi->flags = diff->opts.flags;
  	else
  		pi->flags = 0;
  
  	if (diff && diff->opts.id_abbrev != 0)
  		pi->oid_strlen = diff->opts.id_abbrev;
  	else if (!diff || !diff->repo)
  		pi->oid_strlen = GIT_ABBREV_DEFAULT;
  	else if (git_repository__cvar(
  		&pi->oid_strlen, diff->repo, GIT_CVAR_ABBREV) < 0)
  		return -1;
  
  	pi->oid_strlen += 1; /* for NUL byte */
  
  	if (pi->oid_strlen < 2)
  		pi->oid_strlen = 2;
  	else if (pi->oid_strlen > GIT_OID_HEXSZ + 1)
  		pi->oid_strlen = GIT_OID_HEXSZ + 1;
  
  	memset(&pi->line, 0, sizeof(pi->line));
  	pi->line.old_lineno = -1;
  	pi->line.new_lineno = -1;
  	pi->line.num_lines  = 1;
  
  	return 0;
  }
  
  static char diff_pick_suffix(int mode)
  {
  	if (S_ISDIR(mode))
  		return '/';
  	else if (GIT_PERMS_IS_EXEC(mode)) /* -V536 */
  		/* in git, modes are very regular, so we must have 0100755 mode */
  		return '*';
  	else
  		return ' ';
  }
  
  char git_diff_status_char(git_delta_t status)
  {
  	char code;
  
  	switch (status) {
  	case GIT_DELTA_ADDED:     code = 'A'; break;
  	case GIT_DELTA_DELETED:   code = 'D'; break;
  	case GIT_DELTA_MODIFIED:  code = 'M'; break;
  	case GIT_DELTA_RENAMED:   code = 'R'; break;
  	case GIT_DELTA_COPIED:    code = 'C'; break;
  	case GIT_DELTA_IGNORED:   code = 'I'; break;
  	case GIT_DELTA_UNTRACKED: code = '?'; break;
  	default:                  code = ' '; break;
  	}
  
  	return code;
  }
  
  static int diff_print_one_name_only(
  	const git_diff_delta *delta, float progress, void *data)
  {
  	diff_print_info *pi = data;
  	git_buf *out = pi->buf;
  
  	GIT_UNUSED(progress);
  
  	if ((pi->flags & GIT_DIFF_SHOW_UNMODIFIED) == 0 &&
  		delta->status == GIT_DELTA_UNMODIFIED)
  		return 0;
  
  	git_buf_clear(out);
  	git_buf_puts(out, delta->new_file.path);
  	git_buf_putc(out, '\n');
  	if (git_buf_oom(out))
  		return -1;
  
  	pi->line.origin      = GIT_DIFF_LINE_FILE_HDR;
  	pi->line.content     = git_buf_cstr(out);
  	pi->line.content_len = git_buf_len(out);
  
  	return pi->print_cb(delta, NULL, &pi->line, pi->payload);
  }
  
  static int diff_print_one_name_status(
  	const git_diff_delta *delta, float progress, void *data)
  {
  	diff_print_info *pi = data;
  	git_buf *out = pi->buf;
  	char old_suffix, new_suffix, code = git_diff_status_char(delta->status);
  	int (*strcomp)(const char *, const char *) =
  		pi->diff ? pi->diff->strcomp : git__strcmp;
  
  	GIT_UNUSED(progress);
  
  	if ((pi->flags & GIT_DIFF_SHOW_UNMODIFIED) == 0 && code == ' ')
  		return 0;
  
  	old_suffix = diff_pick_suffix(delta->old_file.mode);
  	new_suffix = diff_pick_suffix(delta->new_file.mode);
  
  	git_buf_clear(out);
  
  	if (delta->old_file.path != delta->new_file.path &&
  		strcomp(delta->old_file.path,delta->new_file.path) != 0)
  		git_buf_printf(out, "%c\t%s%c %s%c\n", code,
  			delta->old_file.path, old_suffix, delta->new_file.path, new_suffix);
  	else if (delta->old_file.mode != delta->new_file.mode &&
  		delta->old_file.mode != 0 && delta->new_file.mode != 0)
  		git_buf_printf(out, "%c\t%s%c %s%c\n", code,
  			delta->old_file.path, old_suffix, delta->new_file.path, new_suffix);
  	else if (old_suffix != ' ')
  		git_buf_printf(out, "%c\t%s%c\n", code, delta->old_file.path, old_suffix);
  	else
  		git_buf_printf(out, "%c\t%s\n", code, delta->old_file.path);
  	if (git_buf_oom(out))
  		return -1;
  
  	pi->line.origin      = GIT_DIFF_LINE_FILE_HDR;
  	pi->line.content     = git_buf_cstr(out);
  	pi->line.content_len = git_buf_len(out);
  
  	return pi->print_cb(delta, NULL, &pi->line, pi->payload);
  }
  
  static int diff_print_one_raw(
  	const git_diff_delta *delta, float progress, void *data)
  {
  	diff_print_info *pi = data;
  	git_buf *out = pi->buf;
  	char code = git_diff_status_char(delta->status);
  	char start_oid[GIT_OID_HEXSZ+1], end_oid[GIT_OID_HEXSZ+1];
  
  	GIT_UNUSED(progress);
  
  	if ((pi->flags & GIT_DIFF_SHOW_UNMODIFIED) == 0 && code == ' ')
  		return 0;
  
  	git_buf_clear(out);
  
  	git_oid_tostr(start_oid, pi->oid_strlen, &delta->old_file.id);
  	git_oid_tostr(end_oid, pi->oid_strlen, &delta->new_file.id);
  
  	git_buf_printf(
  		out, (pi->oid_strlen <= GIT_OID_HEXSZ) ?
  			":%06o %06o %s... %s... %c" : ":%06o %06o %s %s %c",
  		delta->old_file.mode, delta->new_file.mode, start_oid, end_oid, code);
  
  	if (delta->similarity > 0)
  		git_buf_printf(out, "%03u", delta->similarity);
  
  	if (delta->old_file.path != delta->new_file.path)
  		git_buf_printf(
  			out, "\t%s %s\n", delta->old_file.path, delta->new_file.path);
  	else
  		git_buf_printf(
  			out, "\t%s\n", delta->old_file.path ?
  			delta->old_file.path : delta->new_file.path);
  
  	if (git_buf_oom(out))
  		return -1;
  
  	pi->line.origin      = GIT_DIFF_LINE_FILE_HDR;
  	pi->line.content     = git_buf_cstr(out);
  	pi->line.content_len = git_buf_len(out);
  
  	return pi->print_cb(delta, NULL, &pi->line, pi->payload);
  }
  
  static int diff_print_oid_range(
  	git_buf *out, const git_diff_delta *delta, int oid_strlen)
  {
  	char start_oid[GIT_OID_HEXSZ+1], end_oid[GIT_OID_HEXSZ+1];
  
  	git_oid_tostr(start_oid, oid_strlen, &delta->old_file.id);
  	git_oid_tostr(end_oid, oid_strlen, &delta->new_file.id);
  
  	/* TODO: Match git diff more closely */
  	if (delta->old_file.mode == delta->new_file.mode) {
  		git_buf_printf(out, "index %s..%s %o\n",
  			start_oid, end_oid, delta->old_file.mode);
  	} else {
  		if (delta->old_file.mode == 0) {
  			git_buf_printf(out, "new file mode %o\n", delta->new_file.mode);
  		} else if (delta->new_file.mode == 0) {
  			git_buf_printf(out, "deleted file mode %o\n", delta->old_file.mode);
  		} else {
  			git_buf_printf(out, "old mode %o\n", delta->old_file.mode);
  			git_buf_printf(out, "new mode %o\n", delta->new_file.mode);
  		}
  		git_buf_printf(out, "index %s..%s\n", start_oid, end_oid);
  	}
  
  	return git_buf_oom(out) ? -1 : 0;
  }
  
  static int diff_delta_format_with_paths(
  	git_buf *out,
  	const git_diff_delta *delta,
  	const char *oldpfx,
  	const char *newpfx,
  	const char *template)
  {
  	const char *oldpath = delta->old_file.path;
  	const char *newpath = delta->new_file.path;
  
  	if (git_oid_iszero(&delta->old_file.id)) {
  		oldpfx = "";
  		oldpath = "/dev/null";
  	}
  	if (git_oid_iszero(&delta->new_file.id)) {
  		newpfx = "";
  		newpath = "/dev/null";
  	}
  
  	return git_buf_printf(out, template, oldpfx, oldpath, newpfx, newpath);
  }
  
  int git_diff_delta__format_file_header(
  	git_buf *out,
  	const git_diff_delta *delta,
  	const char *oldpfx,
  	const char *newpfx,
  	int oid_strlen)
  {
  	if (!oldpfx)
  		oldpfx = DIFF_OLD_PREFIX_DEFAULT;
  	if (!newpfx)
  		newpfx = DIFF_NEW_PREFIX_DEFAULT;
  	if (!oid_strlen)
  		oid_strlen = GIT_ABBREV_DEFAULT + 1;
  
  	git_buf_clear(out);
  
  	git_buf_printf(out, "diff --git %s%s %s%s\n",
  		oldpfx, delta->old_file.path, newpfx, delta->new_file.path);
  
  	GITERR_CHECK_ERROR(diff_print_oid_range(out, delta, oid_strlen));
  
  	if ((delta->flags & GIT_DIFF_FLAG_BINARY) == 0)
  		diff_delta_format_with_paths(
  			out, delta, oldpfx, newpfx, "--- %s%s\n+++ %s%s\n");
  
  	return git_buf_oom(out) ? -1 : 0;
  }
  
  static int print_binary_hunk(diff_print_info *pi, git_blob *old, git_blob *new)
  {
  	git_buf deflate = GIT_BUF_INIT, delta = GIT_BUF_INIT, *out = NULL;
  	const void *old_data, *new_data;
  	size_t old_data_len, new_data_len, delta_data_len, inflated_len, remain;
  	const char *out_type = "literal";
  	char *ptr;
  	int error;
  
  	old_data = old ? git_blob_rawcontent(old) : NULL;
  	new_data = new ? git_blob_rawcontent(new) : NULL;
  
  	old_data_len = old ? (size_t)git_blob_rawsize(old) : 0;
  	new_data_len = new ? (size_t)git_blob_rawsize(new) : 0;
  
  	out = &deflate;
  	inflated_len = new_data_len;
  
  	if ((error = git_zstream_deflatebuf(
  		&deflate, new_data, new_data_len)) < 0)
  		goto done;
  
  	if (old && new) {
  		void *delta_data;
  
  		delta_data = git_delta(old_data, old_data_len, new_data,
  			new_data_len, &delta_data_len, deflate.size);
  
  		if (delta_data) {
  			error = git_zstream_deflatebuf(&delta, delta_data, delta_data_len);
  			free(delta_data);
  
  			if (error < 0)
  				goto done;
  
  			if (delta.size < deflate.size) {
  				out = &delta;
  				out_type = "delta";
  				inflated_len = delta_data_len;
  			}
  		}
  	}
  
  	git_buf_printf(pi->buf, "%s %" PRIuZ "\n", out_type, inflated_len);
  	pi->line.num_lines++;
  
  	for (ptr = out->ptr, remain = out->size; remain > 0; ) {
  		size_t chunk_len = (52 < remain) ? 52 : remain;
  
  		if (chunk_len <= 26)
  			git_buf_putc(pi->buf, chunk_len + 'A' - 1);
  		else
  			git_buf_putc(pi->buf, chunk_len - 26 + 'a' - 1);
  
  		git_buf_put_base85(pi->buf, ptr, chunk_len);
  		git_buf_putc(pi->buf, '\n');
  
  		if (git_buf_oom(pi->buf)) {
  			error = -1;
  			goto done;
  		}
  
  		ptr += chunk_len;
  		remain -= chunk_len;
  		pi->line.num_lines++;
  	}
  
  done:
  	git_buf_free(&deflate);
  	git_buf_free(&delta);
  
  	return error;
  }
  
  /* git diff --binary 8d7523f~2 8d7523f~1 */
  static int diff_print_patch_file_binary(
  	diff_print_info *pi, const git_diff_delta *delta,
  	const char *oldpfx, const char *newpfx)
  {
  	git_blob *old = NULL, *new = NULL;
  	const git_oid *old_id, *new_id;
  	int error;
  
  	if ((pi->flags & GIT_DIFF_SHOW_BINARY) == 0) {
  		pi->line.num_lines = 1;
  		return diff_delta_format_with_paths(
  			pi->buf, delta, oldpfx, newpfx,
  				"Binary files %s%s and %s%s differ\n");
  	}
  
  	git_buf_printf(pi->buf, "GIT binary patch\n");
  	pi->line.num_lines++;
  
  	old_id = (delta->status != GIT_DELTA_ADDED) ? &delta->old_file.id : NULL;
  	new_id = (delta->status != GIT_DELTA_DELETED) ? &delta->new_file.id : NULL;
  
  	if ((old_id && (error = git_blob_lookup(&old, pi->diff->repo, old_id)) < 0) ||
  		(new_id && (error = git_blob_lookup(&new, pi->diff->repo,new_id)) < 0) ||
  		(error = print_binary_hunk(pi, old, new)) < 0 ||
  		(error = git_buf_putc(pi->buf, '\n')) < 0 ||
  		(error = print_binary_hunk(pi, new, old)) < 0)
  		goto done;
  
  	pi->line.num_lines++;
  
  done:
  	git_blob_free(old);
  	git_blob_free(new);
  
  	return error;
  }
  
  static int diff_print_patch_file(
  	const git_diff_delta *delta, float progress, void *data)
  {
  	int error;
  	diff_print_info *pi = data;
  	const char *oldpfx =
  		pi->diff ? pi->diff->opts.old_prefix : DIFF_OLD_PREFIX_DEFAULT;
  	const char *newpfx =
  		pi->diff ? pi->diff->opts.new_prefix : DIFF_NEW_PREFIX_DEFAULT;
  
  	bool binary = !!(delta->flags & GIT_DIFF_FLAG_BINARY);
  	bool show_binary = !!(pi->flags & GIT_DIFF_SHOW_BINARY);
  	int oid_strlen = binary && show_binary ?
  		GIT_OID_HEXSZ + 1 : pi->oid_strlen;
  
  	GIT_UNUSED(progress);
  
  	if (S_ISDIR(delta->new_file.mode) ||
  		delta->status == GIT_DELTA_UNMODIFIED ||
  		delta->status == GIT_DELTA_IGNORED ||
  		(delta->status == GIT_DELTA_UNTRACKED &&
  		 (pi->flags & GIT_DIFF_SHOW_UNTRACKED_CONTENT) == 0))
  		return 0;
  
  	if ((error = git_diff_delta__format_file_header(
  			pi->buf, delta, oldpfx, newpfx, oid_strlen)) < 0)
  		return error;
  
  	pi->line.origin      = GIT_DIFF_LINE_FILE_HDR;
  	pi->line.content     = git_buf_cstr(pi->buf);
  	pi->line.content_len = git_buf_len(pi->buf);
  
  	if ((error = pi->print_cb(delta, NULL, &pi->line, pi->payload)) != 0)
  		return error;
  
  	if (!binary)
  		return 0;
  
  	git_buf_clear(pi->buf);
  
  	if ((error = diff_print_patch_file_binary(pi, delta, oldpfx, newpfx)) < 0)
  		return error;
  
  	pi->line.origin      = GIT_DIFF_LINE_BINARY;
  	pi->line.content     = git_buf_cstr(pi->buf);
  	pi->line.content_len = git_buf_len(pi->buf);
  
  	return pi->print_cb(delta, NULL, &pi->line, pi->payload);
  }
  
  static int diff_print_patch_hunk(
  	const git_diff_delta *d,
  	const git_diff_hunk *h,
  	void *data)
  {
  	diff_print_info *pi = data;
  
  	if (S_ISDIR(d->new_file.mode))
  		return 0;
  
  	pi->line.origin      = GIT_DIFF_LINE_HUNK_HDR;
  	pi->line.content     = h->header;
  	pi->line.content_len = h->header_len;
  
  	return pi->print_cb(d, h, &pi->line, pi->payload);
  }
  
  static int diff_print_patch_line(
  	const git_diff_delta *delta,
  	const git_diff_hunk *hunk,
  	const git_diff_line *line,
  	void *data)
  {
  	diff_print_info *pi = data;
  
  	if (S_ISDIR(delta->new_file.mode))
  		return 0;
  
  	return pi->print_cb(delta, hunk, line, pi->payload);
  }
  
  /* print a git_diff to an output callback */
  int git_diff_print(
  	git_diff *diff,
  	git_diff_format_t format,
  	git_diff_line_cb print_cb,
  	void *payload)
  {
  	int error;
  	git_buf buf = GIT_BUF_INIT;
  	diff_print_info pi;
  	git_diff_file_cb print_file = NULL;
  	git_diff_hunk_cb print_hunk = NULL;
  	git_diff_line_cb print_line = NULL;
  
  	switch (format) {
  	case GIT_DIFF_FORMAT_PATCH:
  		print_file = diff_print_patch_file;
  		print_hunk = diff_print_patch_hunk;
  		print_line = diff_print_patch_line;
  		break;
  	case GIT_DIFF_FORMAT_PATCH_HEADER:
  		print_file = diff_print_patch_file;
  		break;
  	case GIT_DIFF_FORMAT_RAW:
  		print_file = diff_print_one_raw;
  		break;
  	case GIT_DIFF_FORMAT_NAME_ONLY:
  		print_file = diff_print_one_name_only;
  		break;
  	case GIT_DIFF_FORMAT_NAME_STATUS:
  		print_file = diff_print_one_name_status;
  		break;
  	default:
  		giterr_set(GITERR_INVALID, "Unknown diff output format (%d)", format);
  		return -1;
  	}
  
  	if (!(error = diff_print_info_init(
  			&pi, &buf, diff, format, print_cb, payload)))
  	{
  		error = git_diff_foreach(
  			diff, print_file, print_hunk, print_line, &pi);
  
  		if (error) /* make sure error message is set */
  			giterr_set_after_callback_function(error, "git_diff_print");
  	}
  
  	git_buf_free(&buf);
  
  	return error;
  }
  
  /* print a git_patch to an output callback */
  int git_patch_print(
  	git_patch *patch,
  	git_diff_line_cb print_cb,
  	void *payload)
  {
  	int error;
  	git_buf temp = GIT_BUF_INIT;
  	diff_print_info pi;
  
  	assert(patch && print_cb);
  
  	if (!(error = diff_print_info_init(
  			&pi, &temp, git_patch__diff(patch),
  			GIT_DIFF_FORMAT_PATCH, print_cb, payload)))
  	{
  		error = git_patch__invoke_callbacks(
  			patch, diff_print_patch_file, diff_print_patch_hunk,
  			diff_print_patch_line, &pi);
  
  		if (error) /* make sure error message is set */
  			giterr_set_after_callback_function(error, "git_patch_print");
  	}
  
  	git_buf_free(&temp);
  
  	return error;
  }
  
  int git_diff_print_callback__to_buf(
  	const git_diff_delta *delta,
  	const git_diff_hunk *hunk,
  	const git_diff_line *line,
  	void *payload)
  {
  	git_buf *output = payload;
  	GIT_UNUSED(delta); GIT_UNUSED(hunk);
  
  	if (!output) {
  		giterr_set(GITERR_INVALID, "Buffer pointer must be provided");
  		return -1;
  	}
  
  	if (line->origin == GIT_DIFF_LINE_ADDITION ||
  		line->origin == GIT_DIFF_LINE_DELETION ||
  		line->origin == GIT_DIFF_LINE_CONTEXT)
  		git_buf_putc(output, line->origin);
  
  	return git_buf_put(output, line->content, line->content_len);
  }
  
  int git_diff_print_callback__to_file_handle(
  	const git_diff_delta *delta,
  	const git_diff_hunk *hunk,
  	const git_diff_line *line,
  	void *payload)
  {
  	FILE *fp = payload ? payload : stdout;
  
  	GIT_UNUSED(delta); GIT_UNUSED(hunk);
  
  	if (line->origin == GIT_DIFF_LINE_CONTEXT ||
  		line->origin == GIT_DIFF_LINE_ADDITION ||
  		line->origin == GIT_DIFF_LINE_DELETION)
  		fputc(line->origin, fp);
  	fwrite(line->content, 1, line->content_len, fp);
  	return 0;
  }
  
  /* print a git_patch to a git_buf */
  int git_patch_to_buf(git_buf *out, git_patch *patch)
  {
  	assert(out && patch);
  	git_buf_sanitize(out);
  	return git_patch_print(patch, git_diff_print_callback__to_buf, out);
  }
  

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