From: Vsevolod Stakhov <vsevolod@rspamd.com>
Date: Sat, 14 Feb 2026 19:17:22 +0000 (+0000)
Subject: [Feature] Sync UUID v7 random portion with Log-Tag header
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ed3e0a8b0ce6c5ef4c3f3a7e623bdedc9ee1172b;p=thirdparty%2Frspamd.git

[Feature] Sync UUID v7 random portion with Log-Tag header

When an MTA provides a Log-Tag header that overrides the pool UID,
patch the task UUID's random portion (bytes 8-15) to stay in sync.
Uses a fast hash of the tag to derive the bytes while preserving
the UUID v7 variant bits.
---

diff --git a/src/libserver/protocol.c b/src/libserver/protocol.c
index a50f0aedae..092c4855dd 100644
--- a/src/libserver/protocol.c
+++ b/src/libserver/protocol.c
@@ -528,6 +528,8 @@ rspamd_protocol_set_log_tag(struct rspamd_task *task,
 		int len = MIN(tag_len, sizeof(task->task_pool->tag.uid) - 1);
 		memcpy(task->task_pool->tag.uid, tag, len);
 		task->task_pool->tag.uid[len] = '\0';
+		/* Keep UUID random portion in sync with the new log tag */
+		rspamd_uuid_v7_patch_uid(task->task_uuid, tag, tag_len);
 	}
 }
 
diff --git a/src/libutil/util.c b/src/libutil/util.c
index 9c1ea18fe9..7714195c4b 100644
--- a/src/libutil/util.c
+++ b/src/libutil/util.c
@@ -1667,6 +1667,25 @@ int rspamd_uuid_v7(char uuid_out[37], char *opt_uid_buf, gsize uid_buflen, doubl
 	return 0;
 }
 
+void rspamd_uuid_v7_patch_uid(char uuid[37], const char *tag, gsize tag_len)
+{
+	uint8_t bytes[8];
+	char hex[16];
+
+	/* Hash the tag to get 8 bytes for UUID positions 8-15 */
+	uint64_t h = rspamd_cryptobox_fast_hash(tag, tag_len, 0x7569645f763700ULL);
+	memcpy(bytes, &h, sizeof(h));
+
+	/* Preserve variant bits: byte 8 must have top 2 bits = 10 */
+	bytes[0] = 0x80 | (bytes[0] & 0x3f);
+
+	/* Hex-encode and patch into UUID string:
+	 * positions 19-22 = bytes 8-9, positions 24-35 = bytes 10-15 */
+	rspamd_encode_hex_buf(bytes, 8, hex, sizeof(hex));
+	memcpy(uuid + 19, hex, 4);
+	memcpy(uuid + 24, hex + 4, 12);
+}
+
 int rspamd_shmem_mkstemp(char *pattern)
 {
 	int fd = -1;
diff --git a/src/libutil/util.h b/src/libutil/util.h
index 34b7a685ab..0cff29b724 100644
--- a/src/libutil/util.h
+++ b/src/libutil/util.h
@@ -390,6 +390,15 @@ void rspamd_random_hex(char *buf, uint64_t len);
  */
 int rspamd_uuid_v7(char uuid_out[37], char *opt_uid_buf, gsize uid_buflen, double timestamp);
 
+/**
+ * Patch UUID v7 random portion (bytes 8-15) to match a new log tag.
+ * Hashes the tag to derive bytes, preserves timestamp and version/variant bits.
+ * @param uuid UUID string to patch in place (36 chars + NUL)
+ * @param tag new log tag value
+ * @param tag_len length of tag
+ */
+void rspamd_uuid_v7_patch_uid(char uuid[37], const char *tag, gsize tag_len);
+
 /**
  * Returns
  * @param pattern pattern to create (should end with some number of X symbols), modified by this function