Sync with 2.21.1

* maint-2.21: (42 commits)
  Git 2.21.1
  mingw: sh arguments need quoting in more circumstances
  mingw: fix quoting of empty arguments for `sh`
  mingw: use MSYS2 quoting even when spawning shell scripts
  mingw: detect when MSYS2's sh is to be spawned more robustly
  t7415: drop v2.20.x-specific work-around
  Git 2.20.2
  t7415: adjust test for dubiously-nested submodule gitdirs for v2.20.x
  Git 2.19.3
  Git 2.18.2
  Git 2.17.3
  Git 2.16.6
  test-drop-caches: use `has_dos_drive_prefix()`
  Git 2.15.4
  Git 2.14.6
  mingw: handle `subst`-ed "DOS drives"
  mingw: refuse to access paths with trailing spaces or periods
  mingw: refuse to access paths with illegal characters
  unpack-trees: let merged_entry() pass through do_add_entry()'s errors
  quote-stress-test: offer to test quoting arguments for MSYS2 sh
  ...

Documentation/RelNotes/2.14.6.txt

@@ -0,0 +1,54 @@
+Git v2.14.6 Release Notes
+=========================
+
+This release addresses the security issues CVE-2019-1348,
+CVE-2019-1349, CVE-2019-1350, CVE-2019-1351, CVE-2019-1352,
+CVE-2019-1353, CVE-2019-1354, and CVE-2019-1387.
+
+Fixes since v2.14.5
+-------------------
+
+ * CVE-2019-1348:
+   The --export-marks option of git fast-import is exposed also via
+   the in-stream command feature export-marks=... and it allows
+   overwriting arbitrary paths.
+
+ * CVE-2019-1349:
+   When submodules are cloned recursively, under certain circumstances
+   Git could be fooled into using the same Git directory twice. We now
+   require the directory to be empty.
+
+ * CVE-2019-1350:
+   Incorrect quoting of command-line arguments allowed remote code
+   execution during a recursive clone in conjunction with SSH URLs.
+
+ * CVE-2019-1351:
+   While the only permitted drive letters for physical drives on
+   Windows are letters of the US-English alphabet, this restriction
+   does not apply to virtual drives assigned via subst <letter>:
+   <path>. Git mistook such paths for relative paths, allowing writing
+   outside of the worktree while cloning.
+
+ * CVE-2019-1352:
+   Git was unaware of NTFS Alternate Data Streams, allowing files
+   inside the .git/ directory to be overwritten during a clone.
+
+ * CVE-2019-1353:
+   When running Git in the Windows Subsystem for Linux (also known as
+   "WSL") while accessing a working directory on a regular Windows
+   drive, none of the NTFS protections were active.
+
+ * CVE-2019-1354:
+   Filenames on Linux/Unix can contain backslashes. On Windows,
+   backslashes are directory separators. Git did not use to refuse to
+   write out tracked files with such filenames.
+
+ * CVE-2019-1387:
+   Recursive clones are currently affected by a vulnerability that is
+   caused by too-lax validation of submodule names, allowing very
+   targeted attacks via remote code execution in recursive clones.
+
+Credit for finding these vulnerabilities goes to Microsoft Security
+Response Center, in particular to Nicolas Joly. The `fast-import`
+fixes were provided by Jeff King, the other fixes by Johannes
+Schindelin with help from Garima Singh.

Documentation/RelNotes/2.15.4.txt

@@ -0,0 +1,11 @@
+Git v2.15.4 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.14.6 to address
+the security issues CVE-2019-1348, CVE-2019-1349, CVE-2019-1350,
+CVE-2019-1351, CVE-2019-1352, CVE-2019-1353, CVE-2019-1354, and
+CVE-2019-1387; see the release notes for that version for details.
+
+In conjunction with a vulnerability that was fixed in v2.20.2,
+`.gitmodules` is no longer allowed to contain entries of the form
+`submodule.<name>.update=!command`.

Documentation/RelNotes/2.16.6.txt

@@ -0,0 +1,8 @@
+Git v2.16.6 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.14.6 and in
+v2.15.4 addressing the security issues CVE-2019-1348, CVE-2019-1349,
+CVE-2019-1350, CVE-2019-1351, CVE-2019-1352, CVE-2019-1353,
+CVE-2019-1354, and CVE-2019-1387; see the release notes for those
+versions for details.

Documentation/RelNotes/2.17.3.txt

@@ -0,0 +1,12 @@
+Git v2.17.3 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.14.6 and in
+v2.15.4 addressing the security issues CVE-2019-1348, CVE-2019-1349,
+CVE-2019-1350, CVE-2019-1351, CVE-2019-1352, CVE-2019-1353,
+CVE-2019-1354, and CVE-2019-1387; see the release notes for those
+versions for details.
+
+In addition, `git fsck` was taught to identify `.gitmodules` entries
+of the form `submodule.<name>.update=!command`, which have been
+disallowed in v2.15.4.

Documentation/RelNotes/2.18.2.txt

@@ -0,0 +1,8 @@
+Git v2.18.2 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.14.6, v2.15.4
+and in v2.17.3, addressing the security issues CVE-2019-1348,
+CVE-2019-1349, CVE-2019-1350, CVE-2019-1351, CVE-2019-1352,
+CVE-2019-1353, CVE-2019-1354, and CVE-2019-1387; see the release notes
+for those versions for details.

Documentation/RelNotes/2.19.3.txt

@@ -0,0 +1,8 @@
+Git v2.19.3 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.14.6, v2.15.4
+and in v2.17.3, addressing the security issues CVE-2019-1348,
+CVE-2019-1349, CVE-2019-1350, CVE-2019-1351, CVE-2019-1352,
+CVE-2019-1353, CVE-2019-1354, and CVE-2019-1387; see the release notes
+for those versions for details.

Documentation/RelNotes/2.20.2.txt

@@ -0,0 +1,18 @@
+Git v2.20.2 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.14.6, v2.15.4
+and in v2.17.3, addressing the security issues CVE-2019-1348,
+CVE-2019-1349, CVE-2019-1350, CVE-2019-1351, CVE-2019-1352,
+CVE-2019-1353, CVE-2019-1354, and CVE-2019-1387; see the release notes
+for those versions for details.
+
+The change to disallow `submodule.<name>.update=!command` entries in
+`.gitmodules` which was introduced v2.15.4 (and for which v2.17.3
+added explicit fsck checks) fixes the vulnerability in v2.20.x where a
+recursive clone followed by a submodule update could execute code
+contained within the repository without the user explicitly having
+asked for that (CVE-2019-19604).
+
+Credit for finding this vulnerability goes to Joern Schneeweisz,
+credit for the fixes goes to Jonathan Nieder.

Documentation/RelNotes/2.21.1.txt

@@ -0,0 +1,12 @@
+Git v2.21.1 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.14.6, v2.15.4,
+v2.17.3 and in v2.20.2, addressing the security issues CVE-2019-1348,
+CVE-2019-1349, CVE-2019-1350, CVE-2019-1351, CVE-2019-1352,
+CVE-2019-1353, CVE-2019-1354, CVE-2019-1387, and CVE-2019-19604;
+see the release notes for those versions for details.
+
+Additionally, this version also includes a couple of fixes for the
+Windows-specific quoting of command-line arguments when Git executes
+a Unix shell on Windows.

Documentation/git-fast-import.txt

@@ -51,6 +51,21 @@ OPTIONS
 	memory used by fast-import during this run.  Showing this output
 	is currently the default, but can be disabled with --quiet.
 
+--allow-unsafe-features::
+	Many command-line options can be provided as part of the
+	fast-import stream itself by using the `feature` or `option`
+	commands. However, some of these options are unsafe (e.g.,
+	allowing fast-import to access the filesystem outside of the
+	repository). These options are disabled by default, but can be
+	allowed by providing this option on the command line.  This
+	currently impacts only the `export-marks`, `import-marks`, and
+	`import-marks-if-exists` feature commands.
++
+	Only enable this option if you trust the program generating the
+	fast-import stream! This option is enabled automatically for
+	remote-helpers that use the `import` capability, as they are
+	already trusted to run their own code.
+
 Options for Frontends
 ~~~~~~~~~~~~~~~~~~~~~
 

Documentation/gitmodules.txt

@@ -44,9 +44,8 @@ submodule.<name>.update::
 	submodule init` to initialize the configuration variable of
 	the same name. Allowed values here are 'checkout', 'rebase',
 	'merge' or 'none'. See description of 'update' command in
-	linkgit:git-submodule[1] for their meaning. Note that the
-	'!command' form is intentionally ignored here for security
-	reasons.
+	linkgit:git-submodule[1] for their meaning. For security
+	reasons, the '!command' form is not accepted here.
 
 submodule.<name>.branch::
 	A remote branch name for tracking updates in the upstream submodule.

builtin/clone.c

@@ -777,7 +777,7 @@ static int checkout(int submodule_progress)
 
 	if (!err && (option_recurse_submodules.nr > 0)) {
 		struct argv_array args = ARGV_ARRAY_INIT;
-		argv_array_pushl(&args, "submodule", "update", "--init", "--recursive", NULL);
+		argv_array_pushl(&args, "submodule", "update", "--require-init", "--recursive", NULL);
 
 		if (option_shallow_submodules == 1)
 			argv_array_push(&args, "--depth=1");

builtin/submodule--helper.c

@@ -19,6 +19,7 @@
 #include "diffcore.h"
 #include "diff.h"
 #include "object-store.h"
+#include "dir.h"
 
 #define OPT_QUIET (1 << 0)
 #define OPT_CACHED (1 << 1)
@@ -1359,7 +1360,7 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	char *p, *path = NULL, *sm_gitdir;
 	struct strbuf sb = STRBUF_INIT;
 	struct string_list reference = STRING_LIST_INIT_NODUP;
-	int dissociate = 0;
+	int dissociate = 0, require_init = 0;
 	char *sm_alternate = NULL, *error_strategy = NULL;
 
 	struct option module_clone_options[] = {
@@ -1386,6 +1387,8 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 		OPT__QUIET(&quiet, "Suppress output for cloning a submodule"),
 		OPT_BOOL(0, "progress", &progress,
 			   N_("force cloning progress")),
+		OPT_BOOL(0, "require-init", &require_init,
+			   N_("disallow cloning into non-empty directory")),
 		OPT_END()
 	};
 
@@ -1413,6 +1416,10 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	} else
 		path = xstrdup(path);
 
+	if (validate_submodule_git_dir(sm_gitdir, name) < 0)
+		die(_("refusing to create/use '%s' in another submodule's "
+			"git dir"), sm_gitdir);
+
 	if (!file_exists(sm_gitdir)) {
 		if (safe_create_leading_directories_const(sm_gitdir) < 0)
 			die(_("could not create directory '%s'"), sm_gitdir);
@@ -1424,6 +1431,8 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 			die(_("clone of '%s' into submodule path '%s' failed"),
 			    url, path);
 	} else {
+		if (require_init && !access(path, X_OK) && !is_empty_dir(path))
+			die(_("directory not empty: '%s'"), path);
 		if (safe_create_leading_directories_const(path) < 0)
 			die(_("could not create directory '%s'"), path);
 		strbuf_addf(&sb, "%s/index", sm_gitdir);
@@ -1478,6 +1487,8 @@ static void determine_submodule_update_strategy(struct repository *r,
 			die(_("Invalid update mode '%s' configured for submodule path '%s'"),
 				val, path);
 	} else if (sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {
+		if (sub->update_strategy.type == SM_UPDATE_COMMAND)
+			BUG("how did we read update = !command from .gitmodules?");
 		out->type = sub->update_strategy.type;
 		out->command = sub->update_strategy.command;
 	} else
@@ -1536,6 +1547,7 @@ struct submodule_update_clone {
 	int recommend_shallow;
 	struct string_list references;
 	int dissociate;
+	unsigned require_init;
 	const char *depth;
 	const char *recursive_prefix;
 	const char *prefix;
@@ -1554,7 +1566,7 @@ struct submodule_update_clone {
 	int max_jobs;
 };
 #define SUBMODULE_UPDATE_CLONE_INIT {0, MODULE_LIST_INIT, 0, \
-	SUBMODULE_UPDATE_STRATEGY_INIT, 0, 0, -1, STRING_LIST_INIT_DUP, 0, \
+	SUBMODULE_UPDATE_STRATEGY_INIT, 0, 0, -1, STRING_LIST_INIT_DUP, 0, 0, \
 	NULL, NULL, NULL, \
 	NULL, 0, 0, 0, NULL, 0, 0, 1}
 
@@ -1681,6 +1693,8 @@ static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
 		argv_array_pushl(&child->args, "--prefix", suc->prefix, NULL);
 	if (suc->recommend_shallow && sub->recommend_shallow == 1)
 		argv_array_push(&child->args, "--depth=1");
+	if (suc->require_init)
+		argv_array_push(&child->args, "--require-init");
 	argv_array_pushl(&child->args, "--path", sub->path, NULL);
 	argv_array_pushl(&child->args, "--name", sub->name, NULL);
 	argv_array_pushl(&child->args, "--url", url, NULL);
@@ -1870,6 +1884,8 @@ static int update_clone(int argc, const char **argv, const char *prefix)
 		OPT__QUIET(&suc.quiet, N_("don't print cloning progress")),
 		OPT_BOOL(0, "progress", &suc.progress,
 			    N_("force cloning progress")),
+		OPT_BOOL(0, "require-init", &suc.require_init,
+			   N_("disallow cloning into non-empty directory")),
 		OPT_END()
 	};