From: Markus Koschany <apo@debian.org>
Date: Sun, 1 Oct 2023 10:38:47 +0200
Subject: CVE-2023-42114

Upstream-Bug: 3001

Originally created by Jeremy Harris.
---
 src/auths/auth-spa.c | 36 ++++++++++++++++++++++++++++--------
 1 file changed, 28 insertions(+), 8 deletions(-)

diff --git a/src/auths/auth-spa.c b/src/auths/auth-spa.c
index ae8da9c..f3b0b78 100644
--- a/src/auths/auth-spa.c
+++ b/src/auths/auth-spa.c
@@ -1263,15 +1263,10 @@ spa_bytes_add(ptr, header, b, len*2); \
 }
 
 
-#define GetUnicodeString(structPtr, header) \
-unicodeToString(((char*)structPtr) + IVAL(&structPtr->header.offset,0) , SVAL(&structPtr->header.len,0)/2)
-#define GetString(structPtr, header) \
-toString(((CS structPtr) + IVAL(&structPtr->header.offset,0)), SVAL(&structPtr->header.len,0))
-
 #ifdef notdef
 
 #define DumpBuffer(fp, structPtr, header) \
-dumpRaw(fp,(US structPtr)+IVAL(&structPtr->header.offset,0),SVAL(&structPtr->header.len,0))
+ dumpRaw(fp,(US structPtr)+IVAL(&structPtr->header.offset,0),SVAL(&structPtr->header.len,0))
 
 
 static void
@@ -1335,8 +1330,33 @@ toString (char *p, size_t len)
   return buf;
 }
 
+static inline uschar *
+get_challenge_unistr(SPAAuthChallenge * challenge, SPAStrHeader * hdr)
+{
+int off = IVAL(&hdr->offset, 0);
+int len = SVAL(&hdr->len, 0);
+return off + len < sizeof(SPAAuthChallenge)
+  ? US unicodeToString(CS challenge + off, len/2) : US"";
+}
+
+static inline uschar *
+get_challenge_str(SPAAuthChallenge * challenge, SPAStrHeader * hdr)
+{
+int off = IVAL(&hdr->offset, 0);
+int len = SVAL(&hdr->len, 0);
+return off + len < sizeof(SPAAuthChallenge)
+  ? US toString(CS challenge + off, len) : US"";
+}
+
 #ifdef notdef
 
+#define GetUnicodeString(structPtr, header) \
+ unicodeToString(((char*)structPtr) + IVAL(&structPtr->header.offset,0) , SVAL(&structPtr->header.len,0)/2)
+
+#define GetString(structPtr, header) \
+ toString(((CS structPtr) + IVAL(&structPtr->header.offset,0)), SVAL(&structPtr->header.len,0))
+
+
 void
 dumpSmbNtlmAuthRequest (FILE * fp, SPAAuthRequest * request)
 {
@@ -1507,8 +1527,8 @@ spa_build_auth_response (SPAAuthChallenge * challenge,
     }
 
   else domain = d = string_copy(cf & 0x1
-    ? CUS GetUnicodeString(challenge, uDomain)
-    : CUS GetString(challenge, uDomain));
+    ? CUS get_challenge_unistr(challenge, &challenge->uDomain)
+    : CUS get_challenge_str(challenge, &challenge->uDomain));
 
   spa_smb_encrypt(password, challenge->challengeData, lmRespData);
   spa_smb_nt_encrypt(password, challenge->challengeData, ntRespData);