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[PATCH v4 5/6] promisor-remote: check advertised name or URL

From
Christian Couder <christian.couder@gmail.com>
Date
Jan 27, 2025, 15:17 UTC
Message-ID
<20250127151701.2321341-6-christian.couder@gmail.com>
In-Reply-To
<20250127151701.2321341-1-christian.couder@gmail.com>

A previous commit introduced a "promisor.acceptFromServer" configuration variable with only "None" or "All" as valid values.

Let's introduce "KnownName" and "KnownUrl" as valid values for this configuration option to give more choice to a client about which promisor remotes it might accept among those that the server advertised.

In case of "KnownName", the client will accept promisor remotes which are already configured on the client and have the same name as those advertised by the client. This could be useful in a corporate setup where servers and clients are trusted to not switch names and URLs, but where some kind of control is still useful.

In case of "KnownUrl", the client will accept promisor remotes which have both the same name and the same URL configured on the client as the name and URL advertised by the server. This is the most secure option, so it should be used if possible.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---
 Documentation/config/promisor.txt     | 22 ++++++---
 promisor-remote.c                     | 60 ++++++++++++++++++++---
 t/t5710-promisor-remote-capability.sh | 68 +++++++++++++++++++++++++++
 3 files changed, 138 insertions(+), 12 deletions(-)
diff --git a/Documentation/config/promisor.txt b/Documentation/config/promisor.txt
index 9cbfe3e59e..d1364bc018 100644
--- a/Documentation/config/promisor.txt
+++ b/Documentation/config/promisor.txt
@@ -12,9 +12,19 @@ promisor.advertise::
 promisor.acceptFromServer::
 	If set to "all", a client will accept all the promisor remotes
 	a server might advertise using the "promisor-remote"
-	capability. Default is "none", which means no promisor remote
-	advertised by a server will be accepted. By accepting a
-	promisor remote, the client agrees that the server might omit
-	objects that are lazily fetchable from this promisor remote
-	from its responses to "fetch" and "clone" requests from the
-	client. See linkgit:gitprotocol-v2[5].
+	capability. If set to "knownName" the client will accept
+	promisor remotes which are already configured on the client
+	and have the same name as those advertised by the client. This
+	is not very secure, but could be used in a corporate setup
+	where servers and clients are trusted to not switch name and
+	URLs. If set to "knownUrl", the client will accept promisor
+	remotes which have both the same name and the same URL
+	configured on the client as the name and URL advertised by the
+	server. This is more secure than "all" or "knownUrl", so it
+	should be used if possible instead of those options. Default
+	is "none", which means no promisor remote advertised by a
+	server will be accepted. By accepting a promisor remote, the
+	client agrees that the server might omit objects that are
+	lazily fetchable from this promisor remote from its responses
+	to "fetch" and "clone" requests from the client. See
+	linkgit:gitprotocol-v2[5].
diff --git a/promisor-remote.c b/promisor-remote.c
index 5ac282ed27..790a96aa19 100644
--- a/promisor-remote.c
+++ b/promisor-remote.c
@@ -370,30 +370,73 @@ char *promisor_remote_info(struct repository *repo)
 	return strbuf_detach(&sb, NULL);
 }
 
+/*
+ * Find first index of 'vec' where there is 'val'. 'val' is compared
+ * case insensively to the strings in 'vec'. If not found 'vec->nr' is
+ * returned.
+ */
+static size_t strvec_find_index(struct strvec *vec, const char *val)
+{
+	for (size_t i = 0; i < vec->nr; i++)
+		if (!strcasecmp(vec->v[i], val))
+			return i;
+	return vec->nr;
+}
+
 enum accept_promisor {
 	ACCEPT_NONE = 0,
+	ACCEPT_KNOWN_URL,
+	ACCEPT_KNOWN_NAME,
 	ACCEPT_ALL
 };
 
 static int should_accept_remote(enum accept_promisor accept,
-				const char *remote_name UNUSED,
-				const char *remote_url UNUSED)
+				const char *remote_name, const char *remote_url,
+				struct strvec *names, struct strvec *urls)
 {
+	size_t i;
+
 	if (accept == ACCEPT_ALL)
 		return 1;
 
-	BUG("Unhandled 'enum accept_promisor' value '%d'", accept);
+	i = strvec_find_index(names, remote_name);
+
+	if (i >= names->nr)
+		/* We don't know about that remote */
+		return 0;
+
+	if (accept == ACCEPT_KNOWN_NAME)
+		return 1;
+
+	if (accept != ACCEPT_KNOWN_URL)
+		BUG("Unhandled 'enum accept_promisor' value '%d'", accept);
+
+	if (!strcasecmp(urls->v[i], remote_url))
+		return 1;
+
+	warning(_("known remote named '%s' but with url '%s' instead of '%s'"),
+		remote_name, urls->v[i], remote_url);
+
+	return 0;
 }
 
-static void filter_promisor_remote(struct strvec *accepted, const char *info)
+static void filter_promisor_remote(struct repository *repo,
+				   struct strvec *accepted,
+				   const char *info)
 {
 	struct strbuf **remotes;
 	const char *accept_str;
 	enum accept_promisor accept = ACCEPT_NONE;
+	struct strvec names = STRVEC_INIT;
+	struct strvec urls = STRVEC_INIT;
 
 	if (!git_config_get_string_tmp("promisor.acceptfromserver", &accept_str)) {
 		if (!accept_str || !*accept_str || !strcasecmp("None", accept_str))
 			accept = ACCEPT_NONE;
+		else if (!strcasecmp("KnownUrl", accept_str))
+			accept = ACCEPT_KNOWN_URL;
+		else if (!strcasecmp("KnownName", accept_str))
+			accept = ACCEPT_KNOWN_NAME;
 		else if (!strcasecmp("All", accept_str))
 			accept = ACCEPT_ALL;
 		else
@@ -404,6 +447,9 @@ static void filter_promisor_remote(struct strvec *accepted, const char *info)
 	if (accept == ACCEPT_NONE)
 		return;
 
+	if (accept != ACCEPT_ALL)
+		promisor_info_vecs(repo, &names, &urls);
+
 	/* Parse remote info received */
 
 	remotes = strbuf_split_str(info, ';', 0);
@@ -433,7 +479,7 @@ static void filter_promisor_remote(struct strvec *accepted, const char *info)
 		if (remote_url)
 			decoded_url = url_percent_decode(remote_url);
 
-		if (decoded_name && should_accept_remote(accept, decoded_name, decoded_url))
+		if (decoded_name && should_accept_remote(accept, decoded_name, decoded_url, &names, &urls))
 			strvec_push(accepted, decoded_name);
 
 		strbuf_list_free(elems);
@@ -441,6 +487,8 @@ static void filter_promisor_remote(struct strvec *accepted, const char *info)
 		free(decoded_url);
 	}
 
+	strvec_clear(&names);
+	strvec_clear(&urls);
 	strbuf_list_free(remotes);
 }
 
@@ -449,7 +497,7 @@ char *promisor_remote_reply(const char *info)
 	struct strvec accepted = STRVEC_INIT;
 	struct strbuf reply = STRBUF_INIT;
 
-	filter_promisor_remote(&accepted, info);
+	filter_promisor_remote(the_repository, &accepted, info);
 
 	if (!accepted.nr)
 		return NULL;
diff --git a/t/t5710-promisor-remote-capability.sh b/t/t5710-promisor-remote-capability.sh
index 0390c1dbad..5bce99f5eb 100755
--- a/t/t5710-promisor-remote-capability.sh
+++ b/t/t5710-promisor-remote-capability.sh
@@ -160,6 +160,74 @@ test_expect_success "init + fetch with promisor.advertise set to 'true'" '
 	check_missing_objects server 1 "$oid"
 '
 
+test_expect_success "clone with promisor.acceptfromserver set to 'KnownName'" '
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.server2.promisor=true \
+		-c remote.server2.fetch="+refs/heads/*:refs/remotes/server2/*" \
+		-c remote.server2.url="file://$(pwd)/server2" \
+		-c promisor.acceptfromserver=KnownName \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
+	# Check that the largest object is still missing on the server
+	check_missing_objects server 1 "$oid"
+'
+
+test_expect_success "clone with 'KnownName' and different remote names" '
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.serverTwo.promisor=true \
+		-c remote.serverTwo.fetch="+refs/heads/*:refs/remotes/server2/*" \
+		-c remote.serverTwo.url="file://$(pwd)/server2" \
+		-c promisor.acceptfromserver=KnownName \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
+	# Check that the largest object is not missing on the server
+	check_missing_objects server 0 "" &&
+
+	# Reinitialize server so that the largest object is missing again
+	initialize_server 1 "$oid"
+'
+
+test_expect_success "clone with promisor.acceptfromserver set to 'KnownUrl'" '
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.server2.promisor=true \
+		-c remote.server2.fetch="+refs/heads/*:refs/remotes/server2/*" \
+		-c remote.server2.url="file://$(pwd)/server2" \
+		-c promisor.acceptfromserver=KnownUrl \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
+	# Check that the largest object is still missing on the server
+	check_missing_objects server 1 "$oid"
+'
+
+test_expect_success "clone with 'KnownUrl' and different remote urls" '
+	ln -s server2 serverTwo &&
+
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.server2.promisor=true \
+		-c remote.server2.fetch="+refs/heads/*:refs/remotes/server2/*" \
+		-c remote.server2.url="file://$(pwd)/serverTwo" \
+		-c promisor.acceptfromserver=KnownUrl \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
+	# Check that the largest object is not missing on the server
+	check_missing_objects server 0 "" &&
+
+	# Reinitialize server so that the largest object is missing again
+	initialize_server 1 "$oid"
+'
+
 test_expect_success "clone with promisor.advertise set to 'true' but don't delete the client" '
 	git -C server config promisor.advertise true &&
 
-- 
2.46.0.rc0.95.gcbf174a634
Previous: Christian CouderNext: Junio C Hamano
Message 93 of 110 in “Introduce a "promisor-remote" capability”
  1. 0/4 Introduce a "promisor-remote" capabilityChristian Couder, Jul 31, 2024
  2. 1/4 version: refactor strbuf_sanitize()Christian Couder, Jul 31, 2024
  3. Junio C HamanoJul 31, 2024
  4. Christian CouderAug 20, 2024
  5. 2/4 strbuf: refactor strbuf_trim_trailing_ch()Christian Couder, Jul 31, 2024
  6. Junio C HamanoJul 31, 2024
  7. Taylor BlauJul 31, 2024
  8. Christian CouderAug 20, 2024
  9. Christian CouderAug 20, 2024
  10. 3/4 Add 'promisor-remote' capability to protocol v2Christian Couder, Jul 31, 2024
  11. Taylor BlauJul 31, 2024
  12. Christian CouderAug 20, 2024
  13. Junio C HamanoAug 20, 2024
  14. Christian CouderSep 10, 2024
  15. Taylor BlauJul 31, 2024
  16. Christian CouderAug 20, 2024
  17. Junio C HamanoAug 20, 2024
  18. Christian CouderSep 10, 2024
  19. Junio C HamanoSep 10, 2024
  20. Junio C HamanoJul 31, 2024
  21. Junio C HamanoJul 31, 2024
  22. Christian CouderAug 20, 2024
  23. Patrick SteinhardtAug 5, 2024
  24. Junio C HamanoAug 19, 2024
  25. Christian CouderSep 10, 2024
  26. 4/4 promisor-remote: check advertised name or URLChristian Couder, Jul 31, 2024
  27. Junio C HamanoJul 31, 2024
  28. Christian CouderSep 10, 2024
  29. Junio C HamanoJul 31, 2024
  30. Taylor BlauJul 31, 2024
  31. 0/4 Introduce a "promisor-remote" capabilityChristian Couder, Sep 10, 2024
  32. 1/4 version: refactor strbuf_sanitize()Christian Couder, Sep 10, 2024
  33. 2/4 strbuf: refactor strbuf_trim_trailing_ch()Christian Couder, Sep 10, 2024
  34. 3/4 Add 'promisor-remote' capability to protocol v2Christian Couder, Sep 10, 2024
  35. Patrick SteinhardtSep 30, 2024
  36. Christian CouderSep 30, 2024
  37. Patrick SteinhardtOct 1, 2024
  38. Junio C HamanoOct 1, 2024
  39. Patrick SteinhardtNov 6, 2024
  40. Junio C HamanoNov 28, 2024
  41. Christian CouderNov 28, 2024
  42. Junio C HamanoNov 29, 2024
  43. 4/4 promisor-remote: check advertised name or URLChristian Couder, Sep 10, 2024
  44. Patrick SteinhardtSep 30, 2024
  45. Junio C HamanoSep 26, 2024
  46. Christian CouderSep 27, 2024
  47. Junio C HamanoSep 27, 2024
  48. rsbecker@nexbridge.comSep 27, 2024
  49. Kristoffer HaugsbakkSep 28, 2024
  50. Patrick SteinhardtSep 30, 2024
  51. Christian CouderSep 30, 2024
  52. Junio C HamanoSep 30, 2024
  53. Patrick SteinhardtOct 1, 2024
  54. Junio C HamanoSep 30, 2024
  55. brian m. carlsonSep 30, 2024
  56. Junio C HamanoSep 30, 2024
  57. Patrick SteinhardtOct 1, 2024
  58. 0/5 Introduce a "promisor-remote" capabilityChristian Couder, Dec 6, 2024
  59. 1/5 version: refactor strbuf_sanitize()Christian Couder, Dec 6, 2024
  60. Junio C HamanoDec 7, 2024
  61. Christian CouderJan 27, 2025
  62. 2/5 strbuf: refactor strbuf_trim_trailing_ch()Christian Couder, Dec 6, 2024
  63. Junio C HamanoDec 7, 2024
  64. Christian CouderJan 27, 2025
  65. karthik nayakDec 16, 2024
  66. 3/5 Add 'promisor-remote' capability to protocol v2Christian Couder, Dec 6, 2024
  67. Junio C HamanoDec 7, 2024
  68. Christian CouderJan 27, 2025
  69. 4/5 promisor-remote: check advertised name or URLChristian Couder, Dec 6, 2024
  70. 5/5 doc: add technical design doc for large object promisorsChristian Couder, Dec 6, 2024
  71. Junio C HamanoDec 10, 2024
  72. Christian CouderJan 27, 2025
  73. Junio C HamanoDec 10, 2024
  74. Patrick SteinhardtDec 16, 2024
  75. Christian CouderJan 27, 2025
  76. Junio C HamanoJan 27, 2025
  77. Christian CouderFeb 18, 2025
  78. Junio C HamanoDec 9, 2024
  79. Christian CouderDec 9, 2024
  80. Christian CouderDec 9, 2024
  81. Junio C HamanoDec 9, 2024
  82. Christian CouderJan 27, 2025
  83. Junio C HamanoJan 27, 2025
  84. 0/6 Introduce a "promisor-remote" capabilityChristian Couder, Jan 27, 2025
  85. 1/6 version: replace manual ASCII checks with isprint() for clarityChristian Couder, Jan 27, 2025
  86. 2/6 version: refactor redact_non_printables()Christian Couder, Jan 27, 2025
  87. 3/6 version: make redact_non_printables() non-staticChristian Couder, Jan 27, 2025
  88. Patrick SteinhardtJan 30, 2025
  89. Christian CouderFeb 18, 2025
  90. 4/6 Add 'promisor-remote' capability to protocol v2Christian Couder, Jan 27, 2025
  91. Patrick SteinhardtJan 30, 2025
  92. Christian CouderFeb 18, 2025
  93. 5/6 promisor-remote: check advertised name or URLChristian Couder, Jan 27, 2025
  94. Junio C HamanoJan 27, 2025
  95. Junio C HamanoJan 28, 2025
  96. Patrick SteinhardtJan 30, 2025
  97. Christian CouderFeb 18, 2025
  98. Christian CouderFeb 18, 2025
  99. 6/6 doc: add technical design doc for large object promisorsChristian Couder, Jan 27, 2025
  100. Junio C HamanoJan 27, 2025
  101. Christian CouderFeb 18, 2025
  102. 0/3 Introduce a "promisor-remote" capabilityChristian Couder, Feb 18, 2025
  103. 1/3 Add 'promisor-remote' capability to protocol v2Christian Couder, Feb 18, 2025
  104. 2/3 promisor-remote: check advertised name or URLChristian Couder, Feb 18, 2025
  105. 3/3 doc: add technical design doc for large object promisorsChristian Couder, Feb 18, 2025
  106. Patrick SteinhardtFeb 21, 2025
  107. Junio C HamanoMar 3, 2025
  108. Junio C HamanoFeb 18, 2025
  109. Patrick SteinhardtFeb 21, 2025
  110. Junio C HamanoFeb 21, 2025

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