From: Nicholas Wilson <nicholas@nicholaswilson.me.uk>
Date: Sat, 25 Oct 2025 09:50:27 +0000 (+0100)
Subject: Backport of pcre2-10.48-Write-serialization-padding.patch
X-Git-Tag: archive/raspbian/10.46-1_deb13u2+rpi1^2~10
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=de0a195fe719f62ec57bd6103c9ac73e68fab49a;p=pcre2.git

Backport of pcre2-10.48-Write-serialization-padding.patch

Cherry-pick of edc111a6831591f68b5355a08cc9df8be8f35304

Write padding values to ensure pcre2_serialize_encode() outputs defined values (#826)

Fixes low-severity valgrind error reported in GHSA-q7rw-r7qq-2hx6.

(cherry picked from commit efeabb2dc9adfb91abf8feecd8daccb2a38ea94f)
---

diff --git a/src/pcre2_compile_class.c b/src/pcre2_compile_class.c
index 6a73bb9..b710877 100644
--- a/src/pcre2_compile_class.c
+++ b/src/pcre2_compile_class.c
@@ -1774,17 +1774,14 @@ if ((xclass_props & XCLASS_REQUIRED) != 0)
       PUT(code, 0, (uint32_t)(char_lists_size >> 1));
       code += LINK_SIZE;
 
-#if defined PCRE2_DEBUG || defined SUPPORT_VALGRIND
+      /* If we added padding to align the list, initialize the bytes to
+      defined values, so the library is valgrind-clean. It could also
+      be a security concern for clients calling into PCRE2 via bindings
+      from a memory-safe language, if pcre2_serialize_encode() exposes
+      uninitialized memory that may contain sensitive information. */
+
       if ((char_lists_size & 0x2) != 0)
-        {
-        /* In debug the unused 16 bit value is set
-        to a fixed value and marked unused. */
-        ((uint16_t*)data)[-1] = 0x5555;
-#ifdef SUPPORT_VALGRIND
-        VALGRIND_MAKE_MEM_NOACCESS(data - 2, 2);
-#endif
-        }
-#endif
+        ((uint16_t*)data)[-1] = 0xdead;
 
       cb->char_lists_size =
         CLIST_ALIGN_TO(char_lists_size, sizeof(uint32_t));
diff --git a/src/pcre2test.c b/src/pcre2test.c
index 7e3c979..a6696bc 100644
--- a/src/pcre2test.c
+++ b/src/pcre2test.c
@@ -5414,6 +5414,10 @@ uint32_t use_forbid_utf = forbid_utf;
 PCRE2_SIZE patlen;
 PCRE2_SIZE valgrind_access_length;
 PCRE2_SIZE erroroffset;
+int32_t serialize_rc;
+void *serialize_code;
+uint8_t *serialized_bytes;
+PCRE2_SIZE serialized_size;
 
 /* The perltest.sh script supports only / as a delimiter. */
 
@@ -6259,6 +6263,29 @@ if ((pat_patctl.control2 & CTL2_NL_SET) != 0)
 rc = show_pattern_info();
 if (rc != PR_OK) return rc;
 
+/* Verify that the compiled structure can be serialized without generating
+memory errors. */
+
+serialize_code = PTR(compiled_code);
+PCRE2_SERIALIZE_ENCODE(serialize_rc, &serialize_code, 1, &serialized_bytes,
+  &serialized_size, general_context);
+if (serialize_rc != 1)
+  {
+  fprintf(outfile, "** pcre2_serialize_encode() returned %d instead of 1\n",
+    serialize_rc);
+  return PR_ABEND;
+  }
+
+#if defined SUPPORT_VALGRIND
+if (VALGRIND_CHECK_MEM_IS_DEFINED(serialized_bytes, serialized_size) != 0)
+  {
+  fprintf(outfile, "** pcre2_serialize_encode() returned undefined data\n");
+  return PR_ABEND;
+  }
+#endif
+
+PCRE2_SERIALIZE_FREE(serialized_bytes);
+
 /* The "push" control requests that the compiled pattern be remembered on a
 stack. This is mainly for testing the serialization functionality. */