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[PATCH 10/22] send-pack: fix leaking push cert nonce

From
Patrick Steinhardt <ps@pks.im>
Date
Aug 26, 2024, 07:22 UTC
Message-ID
<138a5ded35a43d3aeaa5058ba316a45b7b50b9ef.1724656120.git.ps@pks.im>
In-Reply-To
<cover.1724656120.git.ps@pks.im>

When retrieving the push cert nonce from the server, we first store the constant returned by `server_feature_value()` and then, if the nonce is valid, we duplicate the nonce memory to extend its lifetime. We never free the latter and thus cause a memory leak.

Fix this by storing the limited-lifetime nonce into a scope-local variable such that the long-lived, allocated nonce can be easily freed without having to cast away its constness.

This leak was exposed by t5534, but fixing it is not sufficient to make the whole test suite leak free.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 send-pack.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/send-pack.c b/send-pack.c
index b224ef9fc5e..c37f6ab3c07 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -501,7 +501,7 @@ int send_pack(struct send_pack_args *args,
 	unsigned cmds_sent = 0;
 	int ret;
 	struct async demux;
-	const char *push_cert_nonce = NULL;
+	char *push_cert_nonce = NULL;
 	struct packet_reader reader;
 	int use_bitmaps;
 
@@ -550,10 +550,11 @@ int send_pack(struct send_pack_args *args,
 
 	if (args->push_cert != SEND_PACK_PUSH_CERT_NEVER) {
 		size_t len;
-		push_cert_nonce = server_feature_value("push-cert", &len);
-		if (push_cert_nonce) {
-			reject_invalid_nonce(push_cert_nonce, len);
-			push_cert_nonce = xmemdupz(push_cert_nonce, len);
+		const char *nonce = server_feature_value("push-cert", &len);
+
+		if (nonce) {
+			reject_invalid_nonce(nonce, len);
+			push_cert_nonce = xmemdupz(nonce, len);
 		} else if (args->push_cert == SEND_PACK_PUSH_CERT_ALWAYS) {
 			die(_("the receiving end does not support --signed push"));
 		} else if (args->push_cert == SEND_PACK_PUSH_CERT_IF_ASKED) {
@@ -771,5 +772,6 @@ int send_pack(struct send_pack_args *args,
 	oid_array_clear(&commons);
 	strbuf_release(&req_buf);
 	strbuf_release(&cap_buf);
+	free(push_cert_nonce);
 	return ret;
 }
-- 
2.46.0.164.g477ce5ccd6.dirty
Previous: Patrick SteinhardtNext: Junio C Hamano
Message 18 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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