Merge pull request #4834 from pks-t/pks/v0.27.5

Security release v0.27.5

CHANGELOG.md

+v0.27.5
+-------
+
+This is a security release fixing the following list of issues:
+
+- Submodule URLs and paths with a leading "-" are now ignored.
+  This is due to the recently discovered CVE-2018-17456, which
+  can lead to arbitrary code execution in upstream git. While
+  libgit2 itself is not vulnerable, it can be used to inject
+  options in an implementation which performs a recursive clone
+  by executing an external command.
+
+- When running repack while doing repo writes,
+  `packfile_load__cb()` could see some temporary files in the
+  directory that were bigger than the usual, and makes `memcmp`
+  overflow on the `p->pack_name` string. This issue was reported
+  and fixed by bisho.
+
+- The configuration file parser used unbounded recursion to parse
+  multiline variables, which could lead to a stack overflow. The
+  issue was reported by the oss-fuzz project, issue 10048 and
+  fixed by Nelson Elhage.
+
+- The fix to the unbounded recursion introduced a memory leak in
+  the config parser. While this leak was never in a public
+  release, the oss-fuzz project reported this as issue 10127. The
+  fix was implemented by Nelson Elhage and Patrick Steinhardt.
+
+- When parsing "ok" packets received via the smart protocol, our
+  parsing code did not correctly verify the bounds of the
+  packets, which could result in a heap-buffer overflow. The
+  issue was reported by the oss-fuzz project, issue 9749 and
+  fixed by Patrick Steinhardt.
+
+- The parsing code for the smart protocol has been tightened in
+  general, fixing heap-buffer overflows when parsing the packet
+  type as well as for "ACK" and "unpack" packets. The issue was
+  discovered and fixed by Patrick Steinhardt.
+
+- Fixed potential integer overflows on platforms with 16 bit
+  integers when parsing packets for the smart protocol. The issue
+  was discovered and fixed by Patrick Steinhardt.
+
+- Fixed potential NULL pointer dereference when parsing
+  configuration files which have "include.path" or
+  "includeIf..path" statements without a value.
+
 v0.27.4
 -------
 

include/git2/version.h

@@ -7,10 +7,10 @@
 #ifndef INCLUDE_git_version_h__
 #define INCLUDE_git_version_h__
 
-#define LIBGIT2_VERSION "0.27.4"
+#define LIBGIT2_VERSION "0.27.5"
 #define LIBGIT2_VER_MAJOR 0
 #define LIBGIT2_VER_MINOR 27
-#define LIBGIT2_VER_REVISION 4
+#define LIBGIT2_VER_REVISION 5
 #define LIBGIT2_VER_PATCH 0
 
 #define LIBGIT2_SOVERSION 27

src/config_file.c

@@ -928,6 +928,9 @@ static int parse_include(git_config_parser *reader,
 	char *dir;
 	int result;
 
+	if (!file)
+		return 0;
+
 	if ((result = git_path_dirname_r(&path, reader->file->path)) < 0)
 		return result;
 
@@ -1029,7 +1032,7 @@ static int parse_conditional_include(git_config_parser *reader,
 	size_t i;
 	int error = 0, matches;
 
-	if (!parse_data->repo)
+	if (!parse_data->repo || !file)
 		return 0;
 
 	condition = git__substrdup(section + strlen("includeIf."),

src/config_parse.c

@@ -315,49 +315,51 @@ done:
 
 static int parse_multiline_variable(git_config_parser *reader, git_buf *value, int in_quotes)
 {
-	char *line = NULL, *proc_line = NULL;
 	int quote_count;
-	bool multiline;
+	bool multiline = true;
+
+	while (multiline) {
+		char *line = NULL, *proc_line = NULL;
+		int error;
 
 		/* Check that the next line exists */
 		git_parse_advance_line(&reader->ctx);
 		line = git__strndup(reader->ctx.line, reader->ctx.line_len);
-	if (line == NULL)
-		return -1;
+		GITERR_CHECK_ALLOC(line);
 
-	/* We've reached the end of the file, there is no continuation.
+		/*
+		 * We've reached the end of the file, there is no continuation.
 		 * (this is not an error).
 		 */
 		if (line[0] == '\0') {
-		git__free(line);
-		return 0;
+			error = 0;
+			goto out;
 		}
 
+		/* If it was just a comment, pretend it didn't exist */
 		quote_count = strip_comments(line, !!in_quotes);
+		if (line[0] == '\0')
+			goto next;
 
-	/* If it was just a comment, pretend it didn't exist */
-	if (line[0] == '\0') {
-		git__free(line);
-		return parse_multiline_variable(reader, value, quote_count);
-		/* TODO: unbounded recursion. This **could** be exploitable */
-	}
+		if ((error = unescape_line(&proc_line, &multiline,
+					   line, in_quotes)) < 0)
+			goto out;
 
-	if (unescape_line(&proc_line, &multiline, line, in_quotes) < 0) {
-		git__free(line);
-		return -1;
-	}
-	/* add this line to the multiline var */
+		/* Add this line to the multiline var */
+		if ((error = git_buf_puts(value, proc_line)) < 0)
+			goto out;
 
-	git_buf_puts(value, proc_line);
+next:
 		git__free(line);
 		git__free(proc_line);
+		in_quotes = quote_count;
+		continue;
 
-	/*
-	 * If we need to continue reading the next line, let's just
-	 * keep putting stuff in the buffer
-	 */
-	if (multiline)
-		return parse_multiline_variable(reader, value, quote_count);
+out:
+		git__free(line);
+		git__free(proc_line);
+		return error;
+	}
 
 	return 0;
 }

src/odb_pack.c

@@ -210,7 +210,7 @@ static int packfile_load__cb(void *data, git_buf *path)
 	for (i = 0; i < backend->packs.length; ++i) {
 		struct git_pack_file *p = git_vector_get(&backend->packs, i);
 
-		if (memcmp(p->pack_name, path_str, cmp_len) == 0)
+		if (strncmp(p->pack_name, path_str, cmp_len) == 0)
 			return 0;
 	}
 

src/submodule.c

@@ -1813,6 +1813,14 @@ static int get_value(const char **out, git_config *cfg, git_buf *buf, const char
 	return error;
 }
 
+static bool looks_like_command_line_option(const char *s)
+{
+	if (s && s[0] == '-')
+		return true;
+
+	return false;
+}
+
 static int submodule_read_config(git_submodule *sm, git_config *cfg)
 {
 	git_buf key = GIT_BUF_INIT;
@@ -1826,6 +1834,8 @@ static int submodule_read_config(git_submodule *sm, git_config *cfg)
 
 	if ((error = get_value(&value, cfg, &key, sm->name, "path")) == 0) {
 		in_config = 1;
+		/* We would warn here if we had that API */
+		if (!looks_like_command_line_option(value)) {
 	/*
 	 * TODO: if case insensitive filesystem, then the following strcmp
 	 * should be strcasecmp
@@ -1836,14 +1846,19 @@ static int submodule_read_config(git_submodule *sm, git_config *cfg)
 				sm->path = git__strdup(value);
 				GITERR_CHECK_ALLOC(sm->path);
 			}
+
+		}
 	} else if (error != GIT_ENOTFOUND) {
 		goto cleanup;
 	}
 
 	if ((error = get_value(&value, cfg, &key, sm->name, "url")) == 0) {
+		/* We would warn here if we had that API */
+		if (!looks_like_command_line_option(value)) {
 			in_config = 1;
 			sm->url = git__strdup(value);
 			GITERR_CHECK_ALLOC(sm->url);
+		}
 	} else if (error != GIT_ENOTFOUND) {
 		goto cleanup;
 	}

src/transports/smart.h

@@ -33,14 +33,14 @@
 
 extern bool git_smart__ofs_delta_enabled;
 
-enum git_pkt_type {
+typedef enum {
 	GIT_PKT_CMD,
 	GIT_PKT_FLUSH,
 	GIT_PKT_REF,
 	GIT_PKT_HAVE,
 	GIT_PKT_ACK,
 	GIT_PKT_NAK,
-	GIT_PKT_PACK,
+	GIT_PKT_PACK__UNUSED,
 	GIT_PKT_COMMENT,
 	GIT_PKT_ERR,
 	GIT_PKT_DATA,
@@ -48,7 +48,7 @@ enum git_pkt_type {
 	GIT_PKT_OK,
 	GIT_PKT_NG,
 	GIT_PKT_UNPACK,
-};
+} git_pkt_type;
 
 /* Used for multi_ack and mutli_ack_detailed */
 enum git_ack_status {
@@ -60,11 +60,11 @@ enum git_ack_status {
 
 /* This would be a flush pkt */
 typedef struct {
-	enum git_pkt_type type;
+	git_pkt_type type;
 } git_pkt;
 
 struct git_pkt_cmd {
-	enum git_pkt_type type;
+	git_pkt_type type;
 	char *cmd;
 	char *path;
 	char *host;
@@ -72,50 +72,50 @@ struct git_pkt_cmd {
 
 /* This is a pkt-line with some info in it */
 typedef struct {
-	enum git_pkt_type type;
+	git_pkt_type type;
 	git_remote_head head;
 	char *capabilities;
 } git_pkt_ref;
 
 /* Useful later */
 typedef struct {
-	enum git_pkt_type type;
+	git_pkt_type type;
 	git_oid oid;
 	enum git_ack_status status;
 } git_pkt_ack;
 
 typedef struct {
-	enum git_pkt_type type;
+	git_pkt_type type;
 	char comment[GIT_FLEX_ARRAY];
 } git_pkt_comment;
 
 typedef struct {
-	enum git_pkt_type type;
-	int len;
+	git_pkt_type type;
+	size_t len;
 	char data[GIT_FLEX_ARRAY];
 } git_pkt_data;
 
 typedef git_pkt_data git_pkt_progress;
 
 typedef struct {
-	enum git_pkt_type type;
-	int len;
+	git_pkt_type type;
+	size_t len;
 	char error[GIT_FLEX_ARRAY];
 } git_pkt_err;
 
 typedef struct {
-	enum git_pkt_type type;
+	git_pkt_type type;
 	char *ref;
 } git_pkt_ok;
 
 typedef struct {
-	enum git_pkt_type type;
+	git_pkt_type type;
 	char *ref;
 	char *msg;
 } git_pkt_ng;
 
 typedef struct {
-	enum git_pkt_type type;
+	git_pkt_type type;
 	int unpack_ok;
 } git_pkt_unpack;
 
@@ -189,7 +189,7 @@ int git_smart__get_push_stream(transport_smart *t, git_smart_subtransport_stream
 int git_smart__update_heads(transport_smart *t, git_vector *symrefs);
 
 /* smart_pkt.c */
-int git_pkt_parse_line(git_pkt **head, const char *line, const char **out, size_t len);
+int git_pkt_parse_line(git_pkt **head, const char **endptr, const char *line, size_t linelen);
 int git_pkt_buffer_flush(git_buf *buf);
 int git_pkt_send_flush(GIT_SOCKET s);
 int git_pkt_buffer_done(git_buf *buf);

src/transports/smart_protocol.c

@@ -44,7 +44,7 @@ int git_smart__store_refs(transport_smart *t, int flushes)
 
 	do {
 		if (buf->offset > 0)
-			error = git_pkt_parse_line(&pkt, buf->data, &line_end, buf->offset);
+			error = git_pkt_parse_line(&pkt, &line_end, buf->data, buf->offset);
 		else
 			error = GIT_EBUFS;
 
@@ -209,15 +209,15 @@ int git_smart__detect_caps(git_pkt_ref *pkt, transport_smart_caps *caps, git_vec
 	return 0;
 }
 
-static int recv_pkt(git_pkt **out, gitno_buffer *buf)
+static int recv_pkt(git_pkt **out, git_pkt_type *pkt_type, gitno_buffer *buf)
 {
 	const char *ptr = buf->data, *line_end = ptr;
 	git_pkt *pkt = NULL;
-	int pkt_type, error = 0, ret;
+	int error = 0, ret;
 
 	do {
 		if (buf->offset > 0)
-			error = git_pkt_parse_line(&pkt, ptr, &line_end, buf->offset);
+			error = git_pkt_parse_line(&pkt, &line_end, ptr, buf->offset);
 		else
 			error = GIT_EBUFS;
 
@@ -236,13 +236,14 @@ static int recv_pkt(git_pkt **out, gitno_buffer *buf)
 	} while (error);
 
 	gitno_consume(buf, line_end);
-	pkt_type = pkt->type;
+	if (pkt_type)
+		*pkt_type = pkt->type;
 	if (out != NULL)
 		*out = pkt;
 	else
 		git__free(pkt);
 
-	return pkt_type;
+	return error;
 }
 
 static int store_common(transport_smart *t)
@@ -252,7 +253,7 @@ static int store_common(transport_smart *t)
 	int error;
 
 	do {
-		if ((error = recv_pkt(&pkt, buf)) < 0)
+		if ((error = recv_pkt(&pkt, NULL, buf)) < 0)
 			return error;
 
 		if (pkt->type == GIT_PKT_ACK) {
@@ -320,7 +321,7 @@ static int wait_while_ack(gitno_buffer *buf)
 	while (1) {
 		git__free(pkt);
 
-		if ((error = recv_pkt((git_pkt **)&pkt, buf)) < 0)
+		if ((error = recv_pkt((git_pkt **)&pkt, NULL, buf)) < 0)
 			return error;
 
 		if (pkt->type == GIT_PKT_NAK)
@@ -345,7 +346,8 @@ int git_smart__negotiate_fetch(git_transport *transport, git_repository *repo, c
 	gitno_buffer *buf = &t->buffer;
 	git_buf data = GIT_BUF_INIT;
 	git_revwalk *walk = NULL;
-	int error = -1, pkt_type;
+	int error = -1;
+	git_pkt_type pkt_type;
 	unsigned int i;
 	git_oid oid;
 
@@ -395,16 +397,13 @@ int git_smart__negotiate_fetch(git_transport *transport, git_repository *repo, c
 				if ((error = store_common(t)) < 0)
 					goto on_error;
 			} else {
-				pkt_type = recv_pkt(NULL, buf);
-
-				if (pkt_type == GIT_PKT_ACK) {
+				error = recv_pkt(NULL, &pkt_type, buf);
+				if (error < 0) {
+					goto on_error;
+				} else if (pkt_type == GIT_PKT_ACK) {
 					break;
 				} else if (pkt_type == GIT_PKT_NAK) {
 					continue;
-				} else if (pkt_type < 0) {
-					/* recv_pkt returned an error */
-					error = pkt_type;
-					goto on_error;
 				} else {
 					giterr_set(GITERR_NET, "Unexpected pkt type");
 					error = -1;
@@ -470,10 +469,10 @@ int git_smart__negotiate_fetch(git_transport *transport, git_repository *repo, c
 
 	/* Now let's eat up whatever the server gives us */
 	if (!t->caps.multi_ack && !t->caps.multi_ack_detailed) {
-		pkt_type = recv_pkt(NULL, buf);
+		error = recv_pkt(NULL, &pkt_type, buf);
 
-		if (pkt_type < 0) {
-			return pkt_type;
+		if (error < 0) {
+			return error;
 		} else if (pkt_type != GIT_PKT_ACK && pkt_type != GIT_PKT_NAK) {
 			giterr_set(GITERR_NET, "Unexpected pkt type");
 			return -1;
@@ -594,7 +593,7 @@ int git_smart__download_pack(
 			goto done;
 		}
 
-		if ((error = recv_pkt(&pkt, buf)) >= 0) {
+		if ((error = recv_pkt(&pkt, NULL, buf)) >= 0) {
 			/* Check cancellation after network call */
 			if (t->cancelled.val) {
 				giterr_clear();
@@ -752,7 +751,7 @@ static int add_push_report_sideband_pkt(git_push *push, git_pkt_data *data_pkt,
 	}
 
 	while (line_len > 0) {
-		error = git_pkt_parse_line(&pkt, line, &line_end, line_len);
+		error = git_pkt_parse_line(&pkt, &line_end, line, line_len);
 
 		if (error == GIT_EBUFS) {
 			/* Buffer the data when the inner packet is split
@@ -795,8 +794,8 @@ static int parse_report(transport_smart *transport, git_push *push)
 
 	for (;;) {
 		if (buf->offset > 0)
-			error = git_pkt_parse_line(&pkt, buf->data,
-						   &line_end, buf->offset);
+			error = git_pkt_parse_line(&pkt, &line_end,
+						   buf->data, buf->offset);
 		else
 			error = GIT_EBUFS;
 

tests/config/include.c

@@ -35,6 +35,8 @@ void test_config_include__absolute(void)
 
 	cl_git_pass(git_config_get_string_buf(&buf, cfg, "foo.bar.baz"));
 	cl_assert_equal_s("huzzah", git_buf_cstr(&buf));
+
+	cl_git_pass(p_unlink("config-include-absolute"));
 }
 
 void test_config_include__homedir(void)
@@ -48,6 +50,8 @@ void test_config_include__homedir(void)
 	cl_assert_equal_s("huzzah", git_buf_cstr(&buf));
 
 	cl_sandbox_set_search_path_defaults();
+
+	cl_git_pass(p_unlink("config-include-homedir"));
 }
 
 /* We need to pretend that the variables were defined where the file was included */
@@ -66,6 +70,9 @@ void test_config_include__ordering(void)
 	git_buf_clear(&buf);
 	cl_git_pass(git_config_get_string_buf(&buf, cfg, "foo.bar.baz"));
 	cl_assert_equal_s("huzzah", git_buf_cstr(&buf));
+
+	cl_git_pass(p_unlink("included"));
+	cl_git_pass(p_unlink("including"));
 }
 
 /* We need to pretend that the variables were defined where the file was included */
@@ -76,8 +83,18 @@ void test_config_include__depth(void)
 
 	cl_git_fail(git_config_open_ondisk(&cfg, "a"));
 
-	p_unlink("a");
-	p_unlink("b");
+	cl_git_pass(p_unlink("a"));
+	cl_git_pass(p_unlink("b"));
+}
+
+void test_config_include__empty_path_sanely_handled(void)
+{
+	cl_git_mkfile("a", "[include]\npath");
+	cl_git_pass(git_config_open_ondisk(&cfg, "a"));
+	cl_git_pass(git_config_get_string_buf(&buf, cfg, "include.path"));
+	cl_assert_equal_s("", git_buf_cstr(&buf));
+
+	cl_git_pass(p_unlink("a"));
 }
 
 void test_config_include__missing(void)
@@ -89,6 +106,8 @@ void test_config_include__missing(void)
 	cl_assert(giterr_last() == NULL);
 	cl_git_pass(git_config_get_string_buf(&buf, cfg, "foo.bar"));
 	cl_assert_equal_s("baz", git_buf_cstr(&buf));
+
+	cl_git_pass(p_unlink("including"));
 }
 
 void test_config_include__missing_homedir(void)
@@ -103,6 +122,7 @@ void test_config_include__missing_homedir(void)
 	cl_assert_equal_s("baz", git_buf_cstr(&buf));
 
 	cl_sandbox_set_search_path_defaults();
+	cl_git_pass(p_unlink("including"));
 }
 
 #define replicate10(s) s s s s s s s s s s
@@ -122,6 +142,10 @@ void test_config_include__depth2(void)
 	git_buf_clear(&buf);
 	cl_git_pass(git_config_get_string_buf(&buf, cfg, "foo.bar2"));
 	cl_assert_equal_s("baz2", git_buf_cstr(&buf));
+
+	cl_git_pass(p_unlink("top-level"));
+	cl_git_pass(p_unlink("middle"));
+	cl_git_pass(p_unlink("bottom"));
 }
 
 void test_config_include__removing_include_removes_values(void)
@@ -132,6 +156,9 @@ void test_config_include__removing_include_removes_values(void)
 	cl_git_pass(git_config_open_ondisk(&cfg, "top-level"));
 	cl_git_mkfile("top-level", "");
 	cl_git_fail(git_config_get_string_buf(&buf, cfg, "foo.bar"));
+
+	cl_git_pass(p_unlink("top-level"));
+	cl_git_pass(p_unlink("included"));
 }
 
 void test_config_include__rewriting_include_refreshes_values(void)
@@ -145,6 +172,10 @@ void test_config_include__rewriting_include_refreshes_values(void)
 	cl_git_fail(git_config_get_string_buf(&buf, cfg, "foo.bar"));
 	cl_git_pass(git_config_get_string_buf(&buf, cfg, "first.other"));
 	cl_assert_equal_s(buf.ptr, "value");
+
+	cl_git_pass(p_unlink("top-level"));
+	cl_git_pass(p_unlink("first"));
+	cl_git_pass(p_unlink("second"));
 }
 
 void test_config_include__included_variables_cannot_be_deleted(void)
@@ -154,13 +185,20 @@ void test_config_include__included_variables_cannot_be_deleted(void)
 
 	cl_git_pass(git_config_open_ondisk(&cfg, "top-level"));
 	cl_git_fail(git_config_delete_entry(cfg, "foo.bar"));
+
+	cl_git_pass(p_unlink("top-level"));
+	cl_git_pass(p_unlink("included"));
 }
 
 void test_config_include__included_variables_cannot_be_modified(void)
 {
 	cl_git_mkfile("top-level", "[include]\npath = included\n");
+
 	cl_git_mkfile("included", "[foo]\nbar = value");
 
 	cl_git_pass(git_config_open_ondisk(&cfg, "top-level"));
 	cl_git_fail(git_config_set_string(cfg, "foo.bar", "other-value"));
+
+	cl_git_pass(p_unlink("top-level"));
+	cl_git_pass(p_unlink("included"));
 }

tests/submodule/inject_option.c

+#include "clar_libgit2.h"
+#include "posix.h"
+#include "path.h"
+#include "submodule_helpers.h"
+#include "fileops.h"
+#include "repository.h"
+
+static git_repository *g_repo = NULL;
+
+void test_submodule_inject_option__initialize(void)
+{
+	g_repo = setup_fixture_submodule_simple();
+}
+
+void test_submodule_inject_option__cleanup(void)
+{
+	cl_git_sandbox_cleanup();
+}
+
+static int find_naughty(git_submodule *sm, const char *name, void *payload)
+{
+	int *foundit = (int *) payload;
+
+	GIT_UNUSED(sm);
+
+	if (!git__strcmp("naughty", name))
+		*foundit = true;
+
+	return 0;
+}
+
+void test_submodule_inject_option__url(void)
+{
+	int foundit;
+	git_submodule *sm;
+	git_buf buf = GIT_BUF_INIT;
+
+	cl_git_pass(git_buf_joinpath(&buf, git_repository_workdir(g_repo), ".gitmodules"));
+	cl_git_rewritefile(buf.ptr,
+			   "[submodule \"naughty\"]\n"
+			   "    path = testrepo\n"
+			   "    url = -u./payload\n");
+	git_buf_free(&buf);
+
+	/* We do want to find it, but with the appropriate field empty */
+	foundit = 0;
+	cl_git_pass(git_submodule_foreach(g_repo, find_naughty, &foundit));
+	cl_assert_equal_i(1, foundit);
+
+	cl_git_pass(git_submodule_lookup(&sm, g_repo, "naughty"));
+	cl_assert_equal_s("testrepo", git_submodule_path(sm));
+	cl_assert_equal_p(NULL, git_submodule_url(sm));
+
+	git_submodule_free(sm);
+}
+
+void test_submodule_inject_option__path(void)
+{
+	int foundit;
+	git_submodule *sm;
+	git_buf buf = GIT_BUF_INIT;
+
+	cl_git_pass(git_buf_joinpath(&buf, git_repository_workdir(g_repo), ".gitmodules"));
+	cl_git_rewritefile(buf.ptr,
+			   "[submodule \"naughty\"]\n"
+			   "    path = --something\n"
+			   "    url = blah.git\n");
+	git_buf_free(&buf);
+
+	/* We do want to find it, but with the appropriate field empty */
+	foundit = 0;
+	cl_git_pass(git_submodule_foreach(g_repo, find_naughty, &foundit));
+	cl_assert_equal_i(1, foundit);
+
+	cl_git_pass(git_submodule_lookup(&sm, g_repo, "naughty"));
+	cl_assert_equal_s("naughty", git_submodule_path(sm));
+	cl_assert_equal_s("blah.git", git_submodule_url(sm));
+
+	git_submodule_free(sm);
+}