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[PATCH 11/22] gpg-interface: fix misdesigned signing key interfaces

From
Patrick Steinhardt <ps@pks.im>
Date
Aug 26, 2024, 07:22 UTC
Message-ID
<a1fca8104b345bff4005fcd7e4c8edb67424fd20.1724656120.git.ps@pks.im>
In-Reply-To
<cover.1724656120.git.ps@pks.im>

The interfaces to retrieve signing keys and their IDs are misdesigned as they return string constants even though they indeed allocate memory, which leads to memory leaks. Refactor the code to instead always return allocated strings and let the callers free them accordingly.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 builtin/tag.c          |  3 ++-
 commit.c               |  9 ++++++---
 gpg-interface.c        | 26 +++++++++++++++-----------
 gpg-interface.h        |  4 ++--
 send-pack.c            |  6 ++++--
 t/t5534-push-signed.sh |  1 +
 6 files changed, 30 insertions(+), 19 deletions(-)
diff --git a/builtin/tag.c b/builtin/tag.c
index a1fb218512c..ab3b500543d 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -160,7 +160,7 @@ static int do_sign(struct strbuf *buffer, struct object_id **compat_oid,
 	const struct git_hash_algo *compat = the_repository->compat_hash_algo;
 	struct strbuf sig = STRBUF_INIT, compat_sig = STRBUF_INIT;
 	struct strbuf compat_buf = STRBUF_INIT;
-	const char *keyid = get_signing_key();
+	char *keyid = get_signing_key();
 	int ret = -1;
 
 	if (sign_buffer(buffer, &sig, keyid))
@@ -190,6 +190,7 @@ static int do_sign(struct strbuf *buffer, struct object_id **compat_oid,
 	strbuf_release(&sig);
 	strbuf_release(&compat_sig);
 	strbuf_release(&compat_buf);
+	free(keyid);
 	return ret;
 }
 
diff --git a/commit.c b/commit.c
index 24ab5c1b509..ec9efc189d5 100644
--- a/commit.c
+++ b/commit.c
@@ -1150,11 +1150,14 @@ int add_header_signature(struct strbuf *buf, struct strbuf *sig, const struct gi
 
 static int sign_commit_to_strbuf(struct strbuf *sig, struct strbuf *buf, const char *keyid)
 {
+	char *keyid_to_free = NULL;
+	int ret = 0;
 	if (!keyid || !*keyid)
-		keyid = get_signing_key();
+		keyid = keyid_to_free = get_signing_key();
 	if (sign_buffer(buf, sig, keyid))
-		return -1;
-	return 0;
+		ret = -1;
+	free(keyid_to_free);
+	return ret;
 }
 
 int parse_signed_commit(const struct commit *commit,
diff --git a/gpg-interface.c b/gpg-interface.c
index 6587085cd19..cf6126b5aa0 100644
--- a/gpg-interface.c
+++ b/gpg-interface.c
@@ -45,8 +45,8 @@ struct gpg_format {
 				    size_t signature_size);
 	int (*sign_buffer)(struct strbuf *buffer, struct strbuf *signature,
 			   const char *signing_key);
-	const char *(*get_default_key)(void);
-	const char *(*get_key_id)(void);
+	char *(*get_default_key)(void);
+	char *(*get_key_id)(void);
 };
 
 static const char *openpgp_verify_args[] = {
@@ -86,9 +86,9 @@ static int sign_buffer_gpg(struct strbuf *buffer, struct strbuf *signature,
 static int sign_buffer_ssh(struct strbuf *buffer, struct strbuf *signature,
 			   const char *signing_key);
 
-static const char *get_default_ssh_signing_key(void);
+static char *get_default_ssh_signing_key(void);
 
-static const char *get_ssh_key_id(void);
+static char *get_ssh_key_id(void);
 
 static struct gpg_format gpg_format[] = {
 	{
@@ -847,7 +847,7 @@ static char *get_ssh_key_fingerprint(const char *signing_key)
 }
 
 /* Returns the first public key from an ssh-agent to use for signing */
-static const char *get_default_ssh_signing_key(void)
+static char *get_default_ssh_signing_key(void)
 {
 	struct child_process ssh_default_key = CHILD_PROCESS_INIT;
 	int ret = -1;
@@ -899,12 +899,16 @@ static const char *get_default_ssh_signing_key(void)
 	return default_key;
 }
 
-static const char *get_ssh_key_id(void) {
-	return get_ssh_key_fingerprint(get_signing_key());
+static char *get_ssh_key_id(void)
+{
+	char *signing_key = get_signing_key();
+	char *key_id = get_ssh_key_fingerprint(signing_key);
+	free(signing_key);
+	return key_id;
 }
 
 /* Returns a textual but unique representation of the signing key */
-const char *get_signing_key_id(void)
+char *get_signing_key_id(void)
 {
 	gpg_interface_lazy_init();
 
@@ -916,17 +920,17 @@ const char *get_signing_key_id(void)
 	return get_signing_key();
 }
 
-const char *get_signing_key(void)
+char *get_signing_key(void)
 {
 	gpg_interface_lazy_init();
 
 	if (configured_signing_key)
-		return configured_signing_key;
+		return xstrdup(configured_signing_key);
 	if (use_format->get_default_key) {
 		return use_format->get_default_key();
 	}
 
-	return git_committer_info(IDENT_STRICT | IDENT_NO_DATE);
+	return xstrdup(git_committer_info(IDENT_STRICT | IDENT_NO_DATE));
 }
 
 const char *gpg_trust_level_to_str(enum signature_trust_level level)
diff --git a/gpg-interface.h b/gpg-interface.h
index 7cd98161f7f..e09f12e8d04 100644
--- a/gpg-interface.h
+++ b/gpg-interface.h
@@ -80,13 +80,13 @@ int sign_buffer(struct strbuf *buffer, struct strbuf *signature,
 const char *gpg_trust_level_to_str(enum signature_trust_level level);
 
 void set_signing_key(const char *);
-const char *get_signing_key(void);
+char *get_signing_key(void);
 
 /*
  * Returns a textual unique representation of the signing key in use
  * Either a GPG KeyID or a SSH Key Fingerprint
  */
-const char *get_signing_key_id(void);
+char *get_signing_key_id(void);
 int check_signature(struct signature_check *sigc,
 		    const char *signature, size_t slen);
 void print_signature_buffer(const struct signature_check *sigc,
diff --git a/send-pack.c b/send-pack.c
index c37f6ab3c07..31a62e6a98c 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -348,7 +348,8 @@ static int generate_push_cert(struct strbuf *req_buf,
 {
 	const struct ref *ref;
 	struct string_list_item *item;
-	char *signing_key_id = xstrdup(get_signing_key_id());
+	char *signing_key_id = get_signing_key_id();
+	char *signing_key = get_signing_key();
 	const char *cp, *np;
 	struct strbuf cert = STRBUF_INIT;
 	int update_seen = 0;
@@ -381,7 +382,7 @@ static int generate_push_cert(struct strbuf *req_buf,
 	if (!update_seen)
 		goto free_return;
 
-	if (sign_buffer(&cert, &cert, get_signing_key()))
+	if (sign_buffer(&cert, &cert, signing_key))
 		die(_("failed to sign the push certificate"));
 
 	packet_buf_write(req_buf, "push-cert%c%s", 0, cap_string);
@@ -394,6 +395,7 @@ static int generate_push_cert(struct strbuf *req_buf,
 
 free_return:
 	free(signing_key_id);
+	free(signing_key);
 	strbuf_release(&cert);
 	return update_seen;
 }
diff --git a/t/t5534-push-signed.sh b/t/t5534-push-signed.sh
index c91a62b77af..d43aee0c327 100755
--- a/t/t5534-push-signed.sh
+++ b/t/t5534-push-signed.sh
@@ -5,6 +5,7 @@ test_description='signed push'
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-gpg.sh
 
-- 
2.46.0.164.g477ce5ccd6.dirty
Previous: Junio C HamanoNext: Junio C Hamano
Message 20 of 70 in “Memory leak fixes (pt.6)”
  1. 00/22 Memory leak fixes (pt.6)Patrick Steinhardt, Aug 26, 2024
  2. 01/22 t/test-lib: allow skipping leak checks for passing testsPatrick Steinhardt, Aug 26, 2024
  3. Junio C HamanoAug 27, 2024
  4. Toon claesAug 29, 2024
  5. Patrick SteinhardtAug 30, 2024
  6. 02/22 fetch-pack: fix memory leaks on fetch negotiationPatrick Steinhardt, Aug 26, 2024
  7. 03/22 send-pack: fix leaking common object IDsPatrick Steinhardt, Aug 26, 2024
  8. 04/22 builtin/push: fix leaking refspec query resultPatrick Steinhardt, Aug 26, 2024
  9. Junio C HamanoAug 30, 2024
  10. Patrick SteinhardtSep 2, 2024
  11. 05/22 upload-pack: fix leaking child process data on reachability checksPatrick Steinhardt, Aug 26, 2024
  12. Junio C HamanoAug 30, 2024
  13. 06/22 submodule: fix leaking fetch task dataPatrick Steinhardt, Aug 26, 2024
  14. 07/22 builtin/submodule--helper: fix leaking refs on push-checkPatrick Steinhardt, Aug 26, 2024
  15. 08/22 remote: fix leaking tracking refsPatrick Steinhardt, Aug 26, 2024
  16. Junio C HamanoSep 4, 2024
  17. 09/22 remote: fix leak in reachability check of a remote-tracking refPatrick Steinhardt, Aug 26, 2024
  18. 10/22 send-pack: fix leaking push cert noncePatrick Steinhardt, Aug 26, 2024
  19. Junio C HamanoSep 4, 2024
  20. 11/22 gpg-interface: fix misdesigned signing key interfacesPatrick Steinhardt, Aug 26, 2024
  21. Junio C HamanoSep 4, 2024
  22. 12/22 object: clear grafts when clearing parsed object poolPatrick Steinhardt, Aug 26, 2024
  23. 13/22 shallow: free grafts when unregistering themPatrick Steinhardt, Aug 26, 2024
  24. 14/22 shallow: fix leaking members of `struct shallow_info`Patrick Steinhardt, Aug 26, 2024
  25. Toon claesAug 29, 2024
  26. Junio C HamanoAug 29, 2024
  27. Patrick SteinhardtAug 30, 2024
  28. 15/22 negotiator/skipping: fix leaking commit entriesPatrick Steinhardt, Aug 26, 2024
  29. Calvin WanAug 28, 2024
  30. Josh SteadmonAug 28, 2024
  31. Patrick SteinhardtAug 29, 2024
  32. Calvin WanAug 29, 2024
  33. 16/22 builtin/repack: fix leaking line buffer when packing promisorsPatrick Steinhardt, Aug 26, 2024
  34. Junio C HamanoSep 4, 2024
  35. 17/22 builtin/pack-objects: plug leaking list of keep-packsPatrick Steinhardt, Aug 26, 2024
  36. 18/22 builtin/grep: fix leaking object contextPatrick Steinhardt, Aug 26, 2024
  37. Junio C HamanoSep 4, 2024
  38. 19/22 builtin/fmt-merge-msg: fix leaking buffersPatrick Steinhardt, Aug 26, 2024
  39. 20/22 match-trees: fix leaking prefixes in `shift_tree()`Patrick Steinhardt, Aug 26, 2024
  40. Junio C HamanoSep 4, 2024
  41. 21/22 merge-ort: fix two leaks when handling directory rename modificationsPatrick Steinhardt, Aug 26, 2024
  42. Junio C HamanoSep 4, 2024
  43. Elijah NewrenSep 5, 2024
  44. 22/22 builtin/repack: fix leaking keep-pack listPatrick Steinhardt, Aug 26, 2024
  45. Junio C HamanoSep 4, 2024
  46. 00/22 Memory leak fixes (pt.6)Patrick Steinhardt, Sep 5, 2024
  47. 01/22 t/test-lib: allow skipping leak checks for passing testsPatrick Steinhardt, Sep 5, 2024
  48. 02/22 fetch-pack: fix memory leaks on fetch negotiationPatrick Steinhardt, Sep 5, 2024
  49. 03/22 send-pack: fix leaking common object IDsPatrick Steinhardt, Sep 5, 2024
  50. 04/22 builtin/push: fix leaking refspec query resultPatrick Steinhardt, Sep 5, 2024
  51. 05/22 upload-pack: fix leaking child process data on reachability checksPatrick Steinhardt, Sep 5, 2024
  52. 06/22 submodule: fix leaking fetch task dataPatrick Steinhardt, Sep 5, 2024
  53. 07/22 builtin/submodule--helper: fix leaking refs on push-checkPatrick Steinhardt, Sep 5, 2024
  54. 08/22 remote: fix leaking tracking refsPatrick Steinhardt, Sep 5, 2024
  55. 09/22 remote: fix leak in reachability check of a remote-tracking refPatrick Steinhardt, Sep 5, 2024
  56. 10/22 send-pack: fix leaking push cert noncePatrick Steinhardt, Sep 5, 2024
  57. 11/22 gpg-interface: fix misdesigned signing key interfacesPatrick Steinhardt, Sep 5, 2024
  58. 12/22 object: clear grafts when clearing parsed object poolPatrick Steinhardt, Sep 5, 2024
  59. 13/22 shallow: free grafts when unregistering themPatrick Steinhardt, Sep 5, 2024
  60. 14/22 shallow: fix leaking members of `struct shallow_info`Patrick Steinhardt, Sep 5, 2024
  61. 15/22 negotiator/skipping: fix leaking commit entriesPatrick Steinhardt, Sep 5, 2024
  62. 16/22 builtin/repack: fix leaking line buffer when packing promisorsPatrick Steinhardt, Sep 5, 2024
  63. 17/22 builtin/pack-objects: plug leaking list of keep-packsPatrick Steinhardt, Sep 5, 2024
  64. 18/22 builtin/grep: fix leaking object contextPatrick Steinhardt, Sep 5, 2024
  65. 19/22 builtin/fmt-merge-msg: fix leaking buffersPatrick Steinhardt, Sep 5, 2024
  66. 20/22 match-trees: fix leaking prefixes in `shift_tree()`Patrick Steinhardt, Sep 5, 2024
  67. 21/22 merge-ort: fix two leaks when handling directory rename modificationsPatrick Steinhardt, Sep 5, 2024
  68. 22/22 builtin/repack: fix leaking keep-pack listPatrick Steinhardt, Sep 5, 2024
  69. Junio C HamanoSep 8, 2024
  70. Junio C HamanoSep 12, 2024

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