From: Aki Tuomi <aki.tuomi@open-xchange.com>
Date: Mon, 26 Jan 2026 07:47:16 +0000 (+0200)
Subject: [PATCH] lib-regex: Do not use data stack for replacement string
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[PATCH] lib-regex: Do not use data stack for replacement string

It will get lost when the data stack frame is dropped at the end,
so use heap memory instead.

Gbp-Pq: Name lib-regex-Do-not-use-data-stack-for-replacement-stri.patch
---

diff --git a/src/lib-regex/regex.c b/src/lib-regex/regex.c
index d48b48a..ade57eb 100644
--- a/src/lib-regex/regex.c
+++ b/src/lib-regex/regex.c
@@ -379,7 +379,7 @@ int dregex_code_replace_full(struct dregex_code *code,
 #endif
 	}
 
-	PCRE2_UCHAR *result32 = U"";
+	PCRE2_UCHAR *result32 = NULL;
 	PCRE2_SIZE result_len = 0;
 
 	int ret;
@@ -416,7 +416,7 @@ int dregex_code_replace_full(struct dregex_code *code,
 		}
 
 		if (result_len > 0)
-			result32 = t_new(PCRE2_UCHAR, result_len);
+			result32 = i_new(PCRE2_UCHAR, result_len);
 
 		/* Run it again as we know the buffer size now */
 		code->climit = cpu_limit_init(code->max_cpu_seconds,
@@ -428,10 +428,14 @@ int dregex_code_replace_full(struct dregex_code *code,
 		pcre2_match_data_free(mdata);
 	} while(0); T_END;
 
-	if (ret < 0)
+	if (ret < 0) {
+		i_free(result32);
 		return handle_error(ret, error_r);
-	else if (ret > 0)
+	} else if (ret > 0) {
+		i_assert(result32 != NULL);
 		uni_ucs4_to_utf8(result32, result_len, result_r);
+		i_free(result32);
+	}
 
 	return ret > 0 ? 1 : 0;
 }