Merge tag 'v2.47.1.windows.2' into rebase-to-v2.48.0

This merges Git for Windows v2.47.1(2) which was released on January
14th, 2025, in an embargoed release that was massively coordinated
between GitHub Desktop, Visual Studio, Git Credential Manager, Git LFS,
Git and Git for Windows.

Most notably, this merges in the fixes for:

  * CVE-2024-50349: When prompting the user for a password in the
    terminal, Git does not neutralize control characters.
  * CVE-2024-52005: The sideband channel does not neutralize control
    characters.
  * CVE-2024-52006: Similar to CVE-2020-5260, affecting credential
    helpers that interpret Carriage Returns as newlines.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

Documentation/config.txt

@@ -524,6 +524,8 @@ include::config/sequencer.txt[]
 
 include::config/showbranch.txt[]
 
+include::config/sideband.txt[]
+
 include::config/sparse.txt[]
 
 include::config/splitindex.txt[]

Documentation/config/credential.txt

@@ -22,6 +22,17 @@ credential.useHttpPath::
 	or https URL to be important. Defaults to false. See
 	linkgit:gitcredentials[7] for more information.
 
+credential.sanitizePrompt::
+	By default, user names and hosts that are shown as part of the
+	password prompt are not allowed to contain control characters (they
+	will be URL-encoded by default). Configure this setting to `false` to
+	override that behavior.
+
+credential.protectProtocol::
+	By default, Carriage Return characters are not allowed in the protocol
+	that is used when Git talks to a credential helper. This setting allows
+	users to override this default.
+
 credential.username::
 	If no username is set for a network authentication, use this username
 	by default. See credential.<context>.* below, and

Documentation/config/sideband.txt

@@ -0,0 +1,16 @@
+sideband.allowControlCharacters::
+	By default, control characters that are delivered via the sideband
+	are masked, except ANSI color sequences. This prevents potentially
+	unwanted ANSI escape sequences from being sent to the terminal. Use
+	this config setting to override this behavior:
++
+--
+	color::
+		Allow ANSI color sequences, line feeds and horizontal tabs,
+		but mask all other control characters. This is the default.
+	false::
+		Mask all control characters other than line feeds and
+		horizontal tabs.
+	true::
+		Allow all control characters to be sent to the terminal.
+--

credential.c

@@ -130,6 +130,10 @@ static int credential_config_callback(const char *var, const char *value,
 	}
 	else if (!strcmp(key, "usehttppath"))
 		c->use_http_path = git_config_bool(var, value);
+	else if (!strcmp(key, "sanitizeprompt"))
+		c->sanitize_prompt = git_config_bool(var, value);
+	else if (!strcmp(key, "protectprotocol"))
+		c->protect_protocol = git_config_bool(var, value);
 
 	return 0;
 }
@@ -227,7 +231,8 @@ static void credential_format(struct credential *c, struct strbuf *out)
 		strbuf_addch(out, '@');
 	}
 	if (c->host)
-		strbuf_addstr(out, c->host);
+		strbuf_add_percentencode(out, c->host,
+					 STRBUF_ENCODE_HOST_AND_PORT);
 	if (c->path) {
 		strbuf_addch(out, '/');
 		strbuf_add_percentencode(out, c->path, 0);
@@ -241,7 +246,10 @@ static char *credential_ask_one(const char *what, struct credential *c,
 	struct strbuf prompt = STRBUF_INIT;
 	char *r;
 
-	credential_describe(c, &desc);
+	if (c->sanitize_prompt)
+		credential_format(c, &desc);
+	else
+		credential_describe(c, &desc);
 	if (desc.len)
 		strbuf_addf(&prompt, "%s for '%s': ", what, desc.buf);
 	else
@@ -382,7 +390,8 @@ int credential_read(struct credential *c, FILE *fp,
 	return 0;
 }
 
-static void credential_write_item(FILE *fp, const char *key, const char *value,
+static void credential_write_item(const struct credential *c,
+				  FILE *fp, const char *key, const char *value,
 				  int required)
 {
 	if (!value && required)
@@ -391,41 +400,45 @@ static void credential_write_item(FILE *fp, const char *key, const char *value,
 		return;
 	if (strchr(value, '\n'))
 		die("credential value for %s contains newline", key);
+	if (c->protect_protocol && strchr(value, '\r'))
+		die("credential value for %s contains carriage return\n"
+		    "If this is intended, set `credential.protectProtocol=false`",
+		    key);
 	fprintf(fp, "%s=%s\n", key, value);
 }
 
 void credential_write(const struct credential *c, FILE *fp,
 		      enum credential_op_type op_type)
 {
 	if (credential_has_capability(&c->capa_authtype, op_type))
-		credential_write_item(fp, "capability[]", "authtype", 0);
+		credential_write_item(c, fp, "capability[]", "authtype", 0);
 	if (credential_has_capability(&c->capa_state, op_type))
-		credential_write_item(fp, "capability[]", "state", 0);
+		credential_write_item(c, fp, "capability[]", "state", 0);
 
 	if (credential_has_capability(&c->capa_authtype, op_type)) {
-		credential_write_item(fp, "authtype", c->authtype, 0);
-		credential_write_item(fp, "credential", c->credential, 0);
+		credential_write_item(c, fp, "authtype", c->authtype, 0);
+		credential_write_item(c, fp, "credential", c->credential, 0);
 		if (c->ephemeral)
-			credential_write_item(fp, "ephemeral", "1", 0);
+			credential_write_item(c, fp, "ephemeral", "1", 0);
 	}
-	credential_write_item(fp, "protocol", c->protocol, 1);
-	credential_write_item(fp, "host", c->host, 1);
-	credential_write_item(fp, "path", c->path, 0);
-	credential_write_item(fp, "username", c->username, 0);
-	credential_write_item(fp, "password", c->password, 0);
-	credential_write_item(fp, "oauth_refresh_token", c->oauth_refresh_token, 0);
+	credential_write_item(c, fp, "protocol", c->protocol, 1);
+	credential_write_item(c, fp, "host", c->host, 1);
+	credential_write_item(c, fp, "path", c->path, 0);
+	credential_write_item(c, fp, "username", c->username, 0);
+	credential_write_item(c, fp, "password", c->password, 0);
+	credential_write_item(c, fp, "oauth_refresh_token", c->oauth_refresh_token, 0);
 	if (c->password_expiry_utc != TIME_MAX) {
 		char *s = xstrfmt("%"PRItime, c->password_expiry_utc);
-		credential_write_item(fp, "password_expiry_utc", s, 0);
+		credential_write_item(c, fp, "password_expiry_utc", s, 0);
 		free(s);
 	}
 	for (size_t i = 0; i < c->wwwauth_headers.nr; i++)
-		credential_write_item(fp, "wwwauth[]", c->wwwauth_headers.v[i], 0);
+		credential_write_item(c, fp, "wwwauth[]", c->wwwauth_headers.v[i], 0);
 	if (credential_has_capability(&c->capa_state, op_type)) {
 		if (c->multistage)
-			credential_write_item(fp, "continue", "1", 0);
+			credential_write_item(c, fp, "continue", "1", 0);
 		for (size_t i = 0; i < c->state_headers_to_send.nr; i++)
-			credential_write_item(fp, "state[]", c->state_headers_to_send.v[i], 0);
+			credential_write_item(c, fp, "state[]", c->state_headers_to_send.v[i], 0);
 	}
 }
 

credential.h

@@ -168,7 +168,9 @@ struct credential {
 		 multistage: 1,
 		 quit:1,
 		 use_http_path:1,
-		 username_from_proto:1;
+		 username_from_proto:1,
+		 sanitize_prompt:1,
+		 protect_protocol:1;
 
 	struct credential_capability capa_authtype;
 	struct credential_capability capa_state;
@@ -195,6 +197,8 @@ struct credential {
 	.wwwauth_headers = STRVEC_INIT, \
 	.state_headers = STRVEC_INIT, \
 	.state_headers_to_send = STRVEC_INIT, \
+	.sanitize_prompt = 1, \
+	.protect_protocol = 1, \
 }
 
 /* Initialize a credential structure, setting all fields to empty. */

sideband.c

@@ -26,6 +26,12 @@ static struct keyword_entry keywords[] = {
 	{ "error",	GIT_COLOR_BOLD_RED },
 };
 
+static enum {
+	ALLOW_NO_CONTROL_CHARACTERS = 0,
+	ALLOW_ALL_CONTROL_CHARACTERS = 1,
+	ALLOW_ANSI_COLOR_SEQUENCES = 2
+} allow_control_characters = ALLOW_ANSI_COLOR_SEQUENCES;
+
 /* Returns a color setting (GIT_COLOR_NEVER, etc). */
 static int use_sideband_colors(void)
 {
@@ -39,6 +45,25 @@ static int use_sideband_colors(void)
 	if (use_sideband_colors_cached >= 0)
 		return use_sideband_colors_cached;
 
+	switch (git_config_get_maybe_bool("sideband.allowcontrolcharacters", &i)) {
+	case 0: /* Boolean value */
+		allow_control_characters = i ? ALLOW_ALL_CONTROL_CHARACTERS :
+			ALLOW_NO_CONTROL_CHARACTERS;
+		break;
+	case -1: /* non-Boolean value */
+		if (git_config_get_string_tmp("sideband.allowcontrolcharacters",
+					      &value))
+			; /* huh? `get_maybe_bool()` returned -1 */
+		else if (!strcmp(value, "color"))
+			allow_control_characters = ALLOW_ANSI_COLOR_SEQUENCES;
+		else
+			warning(_("unrecognized value for `sideband."
+				  "allowControlCharacters`: '%s'"), value);
+		break;
+	default:
+		break; /* not configured */
+	}
+
 	if (!git_config_get_string_tmp(key, &value))
 		use_sideband_colors_cached = git_config_colorbool(key, value);
 	else if (!git_config_get_string_tmp("color.ui", &value))
@@ -66,6 +91,55 @@ void list_config_color_sideband_slots(struct string_list *list, const char *pref
 		list_config_item(list, prefix, keywords[i].keyword);
 }
 
+static int handle_ansi_color_sequence(struct strbuf *dest, const char *src, int n)
+{
+	int i;
+
+	/*
+	 * Valid ANSI color sequences are of the form
+	 *
+	 * ESC [ [<n> [; <n>]*] m
+	 */
+
+	if (allow_control_characters != ALLOW_ANSI_COLOR_SEQUENCES ||
+	    n < 3 || src[0] != '\x1b' || src[1] != '[')
+		return 0;
+
+	for (i = 2; i < n; i++) {
+		if (src[i] == 'm') {
+			strbuf_add(dest, src, i + 1);
+			return i;
+		}
+		if (!isdigit(src[i]) && src[i] != ';')
+			break;
+	}
+
+	return 0;
+}
+
+static void strbuf_add_sanitized(struct strbuf *dest, const char *src, int n)
+{
+	int i;
+
+	if (allow_control_characters == ALLOW_ALL_CONTROL_CHARACTERS) {
+		strbuf_add(dest, src, n);
+		return;
+	}
+
+	strbuf_grow(dest, n);
+	for (; n && *src; src++, n--) {
+		if (!iscntrl(*src) || *src == '\t' || *src == '\n')
+			strbuf_addch(dest, *src);
+		else if ((i = handle_ansi_color_sequence(dest, src, n))) {
+			src += i;
+			n -= i;
+		} else {
+			strbuf_addch(dest, '^');
+			strbuf_addch(dest, 0x40 + *src);
+		}
+	}
+}
+
 /*
  * Optionally highlight one keyword in remote output if it appears at the start
  * of the line. This should be called for a single line only, which is
@@ -81,7 +155,7 @@ static void maybe_colorize_sideband(struct strbuf *dest, const char *src, int n)
 	int i;
 
 	if (!want_color_stderr(use_sideband_colors())) {
-		strbuf_add(dest, src, n);
+		strbuf_add_sanitized(dest, src, n);
 		return;
 	}
 
@@ -114,7 +188,7 @@ static void maybe_colorize_sideband(struct strbuf *dest, const char *src, int n)
 		}
 	}
 
-	strbuf_add(dest, src, n);
+	strbuf_add_sanitized(dest, src, n);
 }
 
 

strbuf.c

@@ -497,7 +497,9 @@ void strbuf_add_percentencode(struct strbuf *dst, const char *src, int flags)
 		unsigned char ch = src[i];
 		if (ch <= 0x1F || ch >= 0x7F ||
 		    (ch == '/' && (flags & STRBUF_ENCODE_SLASH)) ||
-		    strchr(URL_UNSAFE_CHARS, ch))
+		    ((flags & STRBUF_ENCODE_HOST_AND_PORT) ?
+		     !isalnum(ch) && !strchr("-.:[]", ch) :
+		     !!strchr(URL_UNSAFE_CHARS, ch)))
 			strbuf_addf(dst, "%%%02X", (unsigned char)ch);
 		else
 			strbuf_addch(dst, ch);

strbuf.h

@@ -356,6 +356,7 @@ void strbuf_expand_bad_format(const char *format, const char *command);
 void strbuf_addbuf_percentquote(struct strbuf *dst, const struct strbuf *src);
 
 #define STRBUF_ENCODE_SLASH 1
+#define STRBUF_ENCODE_HOST_AND_PORT 2
 
 /**
  * Append the contents of a string to a strbuf, percent-encoding any characters

t/t0300-credentials.sh

@@ -76,6 +76,10 @@ test_expect_success 'setup helper scripts' '
 	test -z "$pexpiry" || echo password_expiry_utc=$pexpiry
 	EOF
 
+	write_script git-credential-cntrl-in-username <<-\EOF &&
+	printf "username=\\007latrix Lestrange\\n"
+	EOF
+
 	PATH="$PWD$PATH_SEP$PATH"
 '
 
@@ -696,6 +700,19 @@ test_expect_success 'match percent-encoded values in username' '
 	EOF
 '
 
+test_expect_success 'match percent-encoded values in hostname' '
+	test_config "credential.https://a%20b%20c/.helper" "$HELPER" &&
+	check fill <<-\EOF
+	url=https://a b c/
+	--
+	protocol=https
+	host=a b c
+	username=foo
+	password=bar
+	--
+	EOF
+'
+
 test_expect_success 'fetch with multiple path components' '
 	test_unconfig credential.helper &&
 	test_config credential.https://example.com/foo/repo.git.helper "verbatim foo bar" &&
@@ -885,6 +902,22 @@ test_expect_success 'url parser rejects embedded newlines' '
 	test_cmp expect stderr
 '
 
+test_expect_success 'url parser rejects embedded carriage returns' '
+	test_config credential.helper "!true" &&
+	test_must_fail git credential fill 2>stderr <<-\EOF &&
+	url=https://example%0d.com/
+	EOF
+	cat >expect <<-\EOF &&
+	fatal: credential value for host contains carriage return
+	If this is intended, set `credential.protectProtocol=false`
+	EOF
+	test_cmp expect stderr &&
+	GIT_ASKPASS=true \
+	git -c credential.protectProtocol=false credential fill <<-\EOF
+	url=https://example%0d.com/
+	EOF
+'
+
 test_expect_success 'host-less URLs are parsed as empty host' '
 	check fill "verbatim foo bar" <<-\EOF
 	url=cert:///path/to/cert.pem
@@ -994,4 +1027,20 @@ test_expect_success 'credential config with partial URLs' '
 	test_grep "skipping credential lookup for key" stderr
 '
 
+BEL="$(printf '\007')"
+
+test_expect_success 'interactive prompt is sanitized' '
+	check fill cntrl-in-username <<-EOF
+	protocol=https
+	host=example.org
+	--
+	protocol=https
+	host=example.org
+	username=${BEL}latrix Lestrange
+	password=askpass-password
+	--
+	askpass: Password for ${SQ}https://%07latrix%[email protected]${SQ}:
+	EOF
+'
+
 test_done