From: Peter van Dijk <peter.van.dijk@powerdns.com>
Date: Fri, 17 Mar 2023 10:57:26 +0000 (+0100)
Subject: avoid one unaligned uint16_t access
X-Git-Tag: auth-4.8.0-alpha1~1^2~11
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=38af8ac849d63e88ea5d862444e94165e9fb8218;p=thirdparty%2Fpdns.git

avoid one unaligned uint16_t access
---

diff --git a/ext/lmdb-safe/lmdb-safe.cc b/ext/lmdb-safe/lmdb-safe.cc
index be3ef4561c..083d0661b3 100644
--- a/ext/lmdb-safe/lmdb-safe.cc
+++ b/ext/lmdb-safe/lmdb-safe.cc
@@ -42,7 +42,9 @@ namespace LMDBLS {
 
     size_t headersize = LS_MIN_HEADER_SIZE;
 
-    headersize += ntohs(lsh->d_numextra) * LS_BLOCK_SIZE;
+    uint16_t numextra = (val[LS_NUMEXTRA_OFFSET] << 8) + val[LS_NUMEXTRA_OFFSET+1];
+
+    headersize += numextra * LS_BLOCK_SIZE;
 
     if (val.size() < headersize) {
       throw std::runtime_error("LSheader too short for promised extra data");
diff --git a/ext/lmdb-safe/lmdb-safe.hh b/ext/lmdb-safe/lmdb-safe.hh
index f9ce08ab41..9097d647f3 100644
--- a/ext/lmdb-safe/lmdb-safe.hh
+++ b/ext/lmdb-safe/lmdb-safe.hh
@@ -142,8 +142,9 @@ namespace LMDBLS {
 
   static_assert(sizeof(LSheader)==24, "LSheader size is wrong");
 
-  const size_t LS_MIN_HEADER_SIZE=sizeof(LSheader);  // FIXME: rename this so all code that relies on it breaks - it needs to use LScheckHeaderAndGetSize below
-  const size_t LS_BLOCK_SIZE=8;
+  const size_t LS_MIN_HEADER_SIZE = sizeof(LSheader);
+  const size_t LS_BLOCK_SIZE = 8;
+  const size_t LS_NUMEXTRA_OFFSET = 22;
   const uint8_t LS_FLAG_DELETED = 0x01;
 
   LSheader* LSassertFixedHeaderSize(std::string_view val);