thodg/libgit2/tests/diff/binary.c

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• Hash : 7db25870
  Author :
  Date : 2018-06-29T07:45:18
  

  delta: fix sign-extension of big left-shift Our delta code was originally adapted from JGit, which itself adapted it from git itself. Due to this heritage, we inherited a bug from git.git in how we compute the delta offset, which was fixed upstream in 48fb7deb5 (Fix big left-shifts of unsigned char, 2009-06-17). As explained by Linus: Shifting 'unsigned char' or 'unsigned short' left can result in sign extension errors, since the C integer promotion rules means that the unsigned char/short will get implicitly promoted to a signed 'int' due to the shift (or due to other operations). This normally doesn't matter, but if you shift things up sufficiently, it will now set the sign bit in 'int', and a subsequent cast to a bigger type (eg 'long' or 'unsigned long') will now sign-extend the value despite the original expression being unsigned. One example of this would be something like unsigned long size; unsigned char c; size += c << 24; where despite all the variables being unsigned, 'c << 24' ends up being a signed entity, and will get sign-extended when then doing the addition in an 'unsigned long' type. Since git uses 'unsigned char' pointers extensively, we actually have this bug in a couple of places. In our delta code, we inherited such a bogus shift when computing the offset at which the delta base is to be found. Due to the sign extension we can end up with an offset where all the bits are set. This can allow an arbitrary memory read, as the addition in `base_len < off + len` can now overflow if `off` has all its bits set. Fix the issue by casting the result of `*delta++ << 24UL` to an unsigned integer again. Add a test with a crafted delta that would actually succeed with an out-of-bounds read in case where the cast wouldn't exist. Reported-by: Riccardo Schirone <rschiron@redhat.com> Test-provided-by: Riccardo Schirone <rschiron@redhat.com>

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• tests/diff/binary.c

• #include "clar_libgit2.h"
  
  #include "git2/sys/diff.h"
  
  #include "buffer.h"
  #include "delta.h"
  #include "filebuf.h"
  #include "repository.h"
  
  static git_repository *repo;
  
  void test_diff_binary__initialize(void)
  {
  }
  
  void test_diff_binary__cleanup(void)
  {
  	cl_git_sandbox_cleanup();
  }
  
  void test_patch(
  	const char *one,
  	const char *two,
  	const git_diff_options *opts,
  	const char *expected)
  {
  	git_oid id_one, id_two;
  	git_index *index = NULL;
  	git_commit *commit_one, *commit_two = NULL;
  	git_tree *tree_one, *tree_two;
  	git_diff *diff;
  	git_patch *patch;
  	git_buf actual = GIT_BUF_INIT;
  
  	cl_git_pass(git_oid_fromstr(&id_one, one));
  	cl_git_pass(git_commit_lookup(&commit_one, repo, &id_one));
  	cl_git_pass(git_commit_tree(&tree_one, commit_one));
  
  	if (two) {
  		cl_git_pass(git_oid_fromstr(&id_two, two));
  		cl_git_pass(git_commit_lookup(&commit_two, repo, &id_two));
  		cl_git_pass(git_commit_tree(&tree_two, commit_two));
  	} else {
  		cl_git_pass(git_repository_index(&index, repo));
  		cl_git_pass(git_index_write_tree(&id_two, index));
  		cl_git_pass(git_tree_lookup(&tree_two, repo, &id_two));
  	}
  
  	cl_git_pass(git_diff_tree_to_tree(&diff, repo, tree_one, tree_two, opts));
  
  	cl_git_pass(git_patch_from_diff(&patch, diff, 0));
  	cl_git_pass(git_patch_to_buf(&actual, patch));
  
  	cl_assert_equal_s(expected, actual.ptr);
  
  	git_buf_clear(&actual);
  	cl_git_pass(git_diff_print(diff, GIT_DIFF_FORMAT_PATCH, git_diff_print_callback__to_buf, &actual));
  
  	cl_assert_equal_s(expected, actual.ptr);
  
  	git_buf_dispose(&actual);
  	git_patch_free(patch);
  	git_diff_free(diff);
  	git_tree_free(tree_one);
  	git_tree_free(tree_two);
  	git_commit_free(commit_one);
  	git_commit_free(commit_two);
  	git_index_free(index);
  }
  
  void test_diff_binary__add_normal(void)
  {
  	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
  	const char *expected =
  		"diff --git a/binary.bin b/binary.bin\n" \
  		"new file mode 100644\n" \
  		"index 0000000..bd474b2\n" \
  		"Binary files /dev/null and b/binary.bin differ\n";
  
  	repo = cl_git_sandbox_init("diff_format_email");
  	test_patch(
  		"873806f6f27e631eb0b23e4b56bea2bfac14a373",
  		"897d3af16ca9e420cd071b1c4541bd2b91d04c8c",
  		&opts,
  		expected);
  }
  
  void test_diff_binary__add(void)
  {
  	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
  	const char *expected =
  		"diff --git a/binary.bin b/binary.bin\n" \
  		"new file mode 100644\n" \
  		"index 0000000000000000000000000000000000000000..bd474b2519cc15eab801ff851cc7d50f0dee49a1\n" \
  		"GIT binary patch\n" \
  		"literal 3\n" \
  		"Kc${Nk-~s>u4FC%O\n"
  		"\n" \
  		"literal 0\n" \
  		"Hc$@<O00001\n" \
  		"\n";
  
  	opts.flags = GIT_DIFF_SHOW_BINARY;
  	opts.id_abbrev = GIT_OID_HEXSZ;
  
  	repo = cl_git_sandbox_init("diff_format_email");
  	test_patch(
  		"873806f6f27e631eb0b23e4b56bea2bfac14a373",
  		"897d3af16ca9e420cd071b1c4541bd2b91d04c8c",
  		&opts,
  		expected);
  }
  
  void test_diff_binary__modify_normal(void)
  {
  	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
  	const char *expected =
  		"diff --git a/binary.bin b/binary.bin\n" \
  		"index bd474b2..9ac35ff 100644\n" \
  		"Binary files a/binary.bin and b/binary.bin differ\n";
  
  	repo = cl_git_sandbox_init("diff_format_email");
  	test_patch(
  		"897d3af16ca9e420cd071b1c4541bd2b91d04c8c",
  		"8d7523f6fcb2404257889abe0d96f093d9f524f9",
  		&opts,
  		expected);
  }
  
  void test_diff_binary__modify(void)
  {
  	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
  	const char *expected =
  		"diff --git a/binary.bin b/binary.bin\n" \
  		"index bd474b2519cc15eab801ff851cc7d50f0dee49a1..9ac35ff15cd8864aeafd889e4826a3150f0b06c4 100644\n" \
  		"GIT binary patch\n" \
  		"literal 5\n" \
  		"Mc${NkU}WL~000&M4gdfE\n" \
  		"\n" \
  		"literal 3\n" \
  		"Kc${Nk-~s>u4FC%O\n" \
  		"\n";
  
  	opts.flags = GIT_DIFF_SHOW_BINARY;
  
  	repo = cl_git_sandbox_init("diff_format_email");
  	test_patch(
  		"897d3af16ca9e420cd071b1c4541bd2b91d04c8c",
  		"8d7523f6fcb2404257889abe0d96f093d9f524f9",
  		&opts,
  		expected);
  }
  
  void test_diff_binary__delete_normal(void)
  {
  	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
  	const char *expected =
  		"diff --git a/binary.bin b/binary.bin\n" \
  		"deleted file mode 100644\n" \
  		"index bd474b2..0000000\n" \
  		"Binary files a/binary.bin and /dev/null differ\n";
  
  	repo = cl_git_sandbox_init("diff_format_email");
  	test_patch(
  		"897d3af16ca9e420cd071b1c4541bd2b91d04c8c",
  		"873806f6f27e631eb0b23e4b56bea2bfac14a373",
  		&opts,
  		expected);
  }
  
  void test_diff_binary__delete(void)
  {
  	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
  	const char *expected =
  		"diff --git a/binary.bin b/binary.bin\n" \
  		"deleted file mode 100644\n" \
  		"index bd474b2519cc15eab801ff851cc7d50f0dee49a1..0000000000000000000000000000000000000000\n" \
  		"GIT binary patch\n" \
  		"literal 0\n" \
  		"Hc$@<O00001\n" \
  		"\n" \
  		"literal 3\n" \
  		"Kc${Nk-~s>u4FC%O\n" \
  		"\n";
  
  	opts.flags = GIT_DIFF_SHOW_BINARY;
  	opts.id_abbrev = GIT_OID_HEXSZ;
  
  	repo = cl_git_sandbox_init("diff_format_email");
  	test_patch(
  		"897d3af16ca9e420cd071b1c4541bd2b91d04c8c",
  		"873806f6f27e631eb0b23e4b56bea2bfac14a373",
  		&opts,
  		expected);
  }
  
  void test_diff_binary__delta(void)
  {
  	git_index *index;
  	git_buf contents = GIT_BUF_INIT;
  	size_t i;
  	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
  	const char *expected =
  		"diff --git a/songof7cities.txt b/songof7cities.txt\n" \
  		"index 4210ffd5c390b21dd5483375e75288dea9ede512..cc84ec183351c9944ed90a619ca08911924055b5 100644\n" \
  		"GIT binary patch\n" \
  		"delta 198\n" \
  		"zc$}LmI8{(0BqLQJI6p64AwNwaIJGP_Pa)Ye#M3o+qJ$<Jl;sX*mF<MGCYv&*L7AHu\n" \
  		"zGA1*^gt?gYVN82wTbPO_W)+x<&1+cP;HrPHR>PQ;Y(X&QMK*C5^Br3bjG4d=XI^5@\n" \
  		"JfH567LIG)KJdFSV\n" \
  		"\n" \
  		"delta 198\n" \
  		"zc$}LmI8{(0BqLQJI6p64AwNwaIJGP_Pr*5}Br~;mqJ$<Jl;sX*mF<MGCYv&*L7AHu\n" \
  		"zGA1*^gt?gYVN82wTbPO_W)+x<&1+cP;HrPHR>PQ;Y(X&QMK*C5^Br3bjG4d=XI^5@\n" \
  		"JfH567LIF3FM2!Fd\n" \
  		"\n";
  
  	opts.flags = GIT_DIFF_SHOW_BINARY | GIT_DIFF_FORCE_BINARY;
  	opts.id_abbrev = GIT_OID_HEXSZ;
  
  	repo = cl_git_sandbox_init("renames");
  	cl_git_pass(git_repository_index(&index, repo));
  
  	cl_git_pass(git_futils_readbuffer(&contents, "renames/songof7cities.txt"));
  
  	for (i = 0; i < contents.size - 6; i++) {
  		if (strncmp(&contents.ptr[i], "Cities", 6) == 0)
  			memcpy(&contents.ptr[i], "cITIES", 6);
  	}
  
  	cl_git_rewritefile("renames/songof7cities.txt", contents.ptr);
  	cl_git_pass(git_index_add_bypath(index, "songof7cities.txt"));
  	cl_git_pass(git_index_write(index));
  
  	test_patch(
  		"19dd32dfb1520a64e5bbaae8dce6ef423dfa2f13",
  		NULL,
  		&opts,
  		expected);
  
  	git_index_free(index);
  	git_buf_dispose(&contents);
  }
  
  void test_diff_binary__delta_append(void)
  {
  	git_index *index;
  	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
  	const char *expected =
  		"diff --git a/untimely.txt b/untimely.txt\n" \
  		"index 9a69d960ae94b060f56c2a8702545e2bb1abb935..1111d4f11f4b35bf6759e0fb714fe09731ef0840 100644\n" \
  		"GIT binary patch\n" \
  		"delta 32\n" \
  		"nc%1vf+QYWt3zLL@hC)e3Vu?a>QDRl4f_G*?PG(-ZA}<#J$+QbW\n" \
  		"\n" \
  		"delta 7\n" \
  		"Oc%18D`@*{63ljhg(E~C7\n" \
  		"\n";
  
  	opts.flags = GIT_DIFF_SHOW_BINARY | GIT_DIFF_FORCE_BINARY;
  	opts.id_abbrev = GIT_OID_HEXSZ;
  
  	repo = cl_git_sandbox_init("renames");
  	cl_git_pass(git_repository_index(&index, repo));
  
  	cl_git_append2file("renames/untimely.txt", "Oh that crazy Kipling!\r\n");
  	cl_git_pass(git_index_add_bypath(index, "untimely.txt"));
  	cl_git_pass(git_index_write(index));
  
  	test_patch(
  		"19dd32dfb1520a64e5bbaae8dce6ef423dfa2f13",
  		NULL,
  		&opts,
  		expected);
  
  	git_index_free(index);
  }
  
  void test_diff_binary__empty_for_no_diff(void)
  {
  	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
  	git_oid id;
  	git_commit *commit;
  	git_tree *tree;
  	git_diff *diff;
  	git_buf actual = GIT_BUF_INIT;
  
  	opts.flags = GIT_DIFF_SHOW_BINARY | GIT_DIFF_FORCE_BINARY;
  	opts.id_abbrev = GIT_OID_HEXSZ;
  
  	repo = cl_git_sandbox_init("renames");
  
  	cl_git_pass(git_oid_fromstr(&id, "19dd32dfb1520a64e5bbaae8dce6ef423dfa2f13"));
  	cl_git_pass(git_commit_lookup(&commit, repo, &id));
  	cl_git_pass(git_commit_tree(&tree, commit));
  
  	cl_git_pass(git_diff_tree_to_tree(&diff, repo, tree, tree, &opts));
  	cl_git_pass(git_diff_print(diff, GIT_DIFF_FORMAT_PATCH, git_diff_print_callback__to_buf, &actual));
  
  	cl_assert_equal_s("", actual.ptr);
  
  	git_buf_dispose(&actual);
  	git_diff_free(diff);
  	git_commit_free(commit);
  	git_tree_free(tree);
  }
  
  void test_diff_binary__index_to_workdir(void)
  {
  	git_index *index;
  	git_diff *diff;
  	git_patch *patch;
  	git_buf actual = GIT_BUF_INIT;
  	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
  	const char *expected =
  		"diff --git a/untimely.txt b/untimely.txt\n" \
  		"index 9a69d960ae94b060f56c2a8702545e2bb1abb935..1111d4f11f4b35bf6759e0fb714fe09731ef0840 100644\n" \
  		"GIT binary patch\n" \
  		"delta 32\n" \
  		"nc%1vf+QYWt3zLL@hC)e3Vu?a>QDRl4f_G*?PG(-ZA}<#J$+QbW\n" \
  		"\n" \
  		"delta 7\n" \
  		"Oc%18D`@*{63ljhg(E~C7\n" \
  		"\n";
  
  	opts.flags = GIT_DIFF_SHOW_BINARY | GIT_DIFF_FORCE_BINARY;
  	opts.id_abbrev = GIT_OID_HEXSZ;
  
  	repo = cl_git_sandbox_init("renames");
  	cl_git_pass(git_repository_index(&index, repo));
  
  	cl_git_append2file("renames/untimely.txt", "Oh that crazy Kipling!\r\n");
  
  	cl_git_pass(git_diff_index_to_workdir(&diff, repo, index, &opts));
  
  	cl_git_pass(git_patch_from_diff(&patch, diff, 0));
  	cl_git_pass(git_patch_to_buf(&actual, patch));
  
  	cl_assert_equal_s(expected, actual.ptr);
  
  	cl_git_pass(git_index_add_bypath(index, "untimely.txt"));
  	cl_git_pass(git_index_write(index));
  
  	test_patch(
  		"19dd32dfb1520a64e5bbaae8dce6ef423dfa2f13",
  		NULL,
  		&opts,
  		expected);
  
  	git_buf_dispose(&actual);
  	git_patch_free(patch);
  	git_diff_free(diff);
  	git_index_free(index);
  }
  
  static int print_cb(
  	const git_diff_delta *delta,
  	const git_diff_hunk *hunk,
  	const git_diff_line *line,
  	void *payload)
  {
  	git_buf *buf = (git_buf *)payload;
  
  	GIT_UNUSED(delta);
  
  	if (hunk)
  		git_buf_put(buf, hunk->header, hunk->header_len);
  
  	if (line)
  		git_buf_put(buf, line->content, line->content_len);
  
  	return git_buf_oom(buf) ? -1 : 0;
  }
  
  void test_diff_binary__print_patch_from_diff(void)
  {
  	git_index *index;
  	git_diff *diff;
  	git_buf actual = GIT_BUF_INIT;
  	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
  	const char *expected =
  		"diff --git a/untimely.txt b/untimely.txt\n" \
  		"index 9a69d960ae94b060f56c2a8702545e2bb1abb935..1111d4f11f4b35bf6759e0fb714fe09731ef0840 100644\n" \
  		"GIT binary patch\n" \
  		"delta 32\n" \
  		"nc%1vf+QYWt3zLL@hC)e3Vu?a>QDRl4f_G*?PG(-ZA}<#J$+QbW\n" \
  		"\n" \
  		"delta 7\n" \
  		"Oc%18D`@*{63ljhg(E~C7\n" \
  		"\n";
  
  	opts.flags = GIT_DIFF_SHOW_BINARY | GIT_DIFF_FORCE_BINARY;
  	opts.id_abbrev = GIT_OID_HEXSZ;
  
  	repo = cl_git_sandbox_init("renames");
  	cl_git_pass(git_repository_index(&index, repo));
  
  	cl_git_append2file("renames/untimely.txt", "Oh that crazy Kipling!\r\n");
  
  	cl_git_pass(git_diff_index_to_workdir(&diff, repo, index, &opts));
  
  	cl_git_pass(git_diff_print(diff, GIT_DIFF_FORMAT_PATCH, print_cb, &actual));
  
  	cl_assert_equal_s(expected, actual.ptr);
  
  	git_buf_dispose(&actual);
  	git_diff_free(diff);
  	git_index_free(index);
  }
  
  struct diff_data {
  	char *old_path;
  	git_oid old_id;
  	git_buf old_binary_base85;
  	size_t old_binary_inflatedlen;
  	git_diff_binary_t old_binary_type;
  
  	char *new_path;
  	git_oid new_id;
  	git_buf new_binary_base85;
  	size_t new_binary_inflatedlen;
  	git_diff_binary_t new_binary_type;
  };
  
  static int file_cb(
  	const git_diff_delta *delta,
  	float progress,
  	void *payload)
  {
  	struct diff_data *diff_data = payload;
  
  	GIT_UNUSED(progress);
  
  	if (delta->old_file.path)
  		diff_data->old_path = git__strdup(delta->old_file.path);
  
  	if (delta->new_file.path)
  		diff_data->new_path = git__strdup(delta->new_file.path);
  
  	git_oid_cpy(&diff_data->old_id, &delta->old_file.id);
  	git_oid_cpy(&diff_data->new_id, &delta->new_file.id);
  
  	return 0;
  }
  
  static int binary_cb(
  	const git_diff_delta *delta,
  	const git_diff_binary *binary,
  	void *payload)
  {
  	struct diff_data *diff_data = payload;
  
  	GIT_UNUSED(delta);
  
  	git_buf_encode_base85(&diff_data->old_binary_base85,
  		binary->old_file.data, binary->old_file.datalen);
  	diff_data->old_binary_inflatedlen = binary->old_file.inflatedlen;
  	diff_data->old_binary_type = binary->old_file.type;
  
  	git_buf_encode_base85(&diff_data->new_binary_base85,
  		binary->new_file.data, binary->new_file.datalen);
  	diff_data->new_binary_inflatedlen = binary->new_file.inflatedlen;
  	diff_data->new_binary_type = binary->new_file.type;
  
  	return 0;
  }
  
  static int hunk_cb(
  	const git_diff_delta *delta,
  	const git_diff_hunk *hunk,
  	void *payload)
  {
  	GIT_UNUSED(delta);
  	GIT_UNUSED(hunk);
  	GIT_UNUSED(payload);
  
  	cl_fail("did not expect hunk callback");
  	return 0;
  }
  
  static int line_cb(
  	const git_diff_delta *delta,
  	const git_diff_hunk *hunk,
  	const git_diff_line *line,
  	void *payload)
  {
  	GIT_UNUSED(delta);
  	GIT_UNUSED(hunk);
  	GIT_UNUSED(line);
  	GIT_UNUSED(payload);
  
  	cl_fail("did not expect line callback");
  	return 0;
  }
  
  void test_diff_binary__blob_to_blob(void)
  {
  	git_index *index;
  	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
  	git_blob *old_blob, *new_blob;
  	git_oid old_id, new_id;
  	struct diff_data diff_data = {0};
  
  	opts.flags = GIT_DIFF_SHOW_BINARY | GIT_DIFF_FORCE_BINARY;
  	opts.id_abbrev = GIT_OID_HEXSZ;
  
  	repo = cl_git_sandbox_init("renames");
  	cl_git_pass(git_repository_index__weakptr(&index, repo));
  
  	cl_git_append2file("renames/untimely.txt", "Oh that crazy Kipling!\r\n");
  	cl_git_pass(git_index_add_bypath(index, "untimely.txt"));
  	cl_git_pass(git_index_write(index));
  
  	git_oid_fromstr(&old_id, "9a69d960ae94b060f56c2a8702545e2bb1abb935");
  	git_oid_fromstr(&new_id, "1111d4f11f4b35bf6759e0fb714fe09731ef0840");
  
  	cl_git_pass(git_blob_lookup(&old_blob, repo, &old_id));
  	cl_git_pass(git_blob_lookup(&new_blob, repo, &new_id));
  
  	cl_git_pass(git_diff_blobs(old_blob,
  		"untimely.txt", new_blob, "untimely.txt", &opts,
  		file_cb, binary_cb, hunk_cb, line_cb, &diff_data));
  
  	cl_assert_equal_s("untimely.txt", diff_data.old_path);
  	cl_assert_equal_oid(&old_id, &diff_data.old_id);
  	cl_assert_equal_i(GIT_DIFF_BINARY_DELTA, diff_data.old_binary_type);
  	cl_assert_equal_i(7, diff_data.old_binary_inflatedlen);
  	cl_assert_equal_s("c%18D`@*{63ljhg(E~C7",
  		diff_data.old_binary_base85.ptr);
  
  	cl_assert_equal_s("untimely.txt", diff_data.new_path);
  	cl_assert_equal_oid(&new_id, &diff_data.new_id);
  	cl_assert_equal_i(GIT_DIFF_BINARY_DELTA, diff_data.new_binary_type);
  	cl_assert_equal_i(32, diff_data.new_binary_inflatedlen);
  	cl_assert_equal_s("c%1vf+QYWt3zLL@hC)e3Vu?a>QDRl4f_G*?PG(-ZA}<#J$+QbW",
  		diff_data.new_binary_base85.ptr);
  
  	git_blob_free(old_blob);
  	git_blob_free(new_blob);
  
  	git__free(diff_data.old_path);
  	git__free(diff_data.new_path);
  
  	git_buf_dispose(&diff_data.old_binary_base85);
  	git_buf_dispose(&diff_data.new_binary_base85);
  }
  

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