From c03fae8adf341e26f2c4c8f068a60a72d8504963 Mon Sep 17 00:00:00 2001
From: Jeremy Harris <jgh146exb@wizmail.org>
Date: Mon, 26 May 2014 11:47:30 +0100
Subject: [PATCH] Errorcheck TLS library calls

---
 src/src/tlscert-gnu.c     | 36 +++++++++++++++++++++------
 src/src/tlscert-openssl.c | 51 +++++++++++++++++++++++++++++++++------
 2 files changed, 73 insertions(+), 14 deletions(-)

diff --git a/src/src/tlscert-gnu.c b/src/src/tlscert-gnu.c
index 737637302..3261c4e8d 100644
--- a/src/src/tlscert-gnu.c
+++ b/src/src/tlscert-gnu.c
@@ -26,12 +26,16 @@ tls_export_cert(uschar * buf, size_t buflen, void * cert)
 {
 size_t sz = buflen;
 void * reset_point = store_get(0);
-int fail = 0;
+int fail;
 uschar * cp;
 
-if (gnutls_x509_crt_export((gnutls_x509_crt_t)cert,
-    GNUTLS_X509_FMT_PEM, buf, &sz))
+if ((fail = gnutls_x509_crt_export((gnutls_x509_crt_t)cert,
+    GNUTLS_X509_FMT_PEM, buf, &sz)))
+  {
+  log_write(0, LOG_MAIN, "TLS error in certificate export: %s",
+    gnutls_strerror(fail));
   return 1;
+  }
 if ((cp = string_printing(buf)) != buf)
   {
   Ustrncpy(buf, cp, buflen);
@@ -55,8 +59,12 @@ gnutls_x509_crt_init(&crt);
 
 datum.data = string_unprinting(US buf);
 datum.size = Ustrlen(datum.data);
-if (gnutls_x509_crt_import(crt, &datum, GNUTLS_X509_FMT_PEM))
+if ((fail = gnutls_x509_crt_import(crt, &datum, GNUTLS_X509_FMT_PEM)))
+  {
+  log_write(0, LOG_MAIN, "TLS error in certificate import: %s",
+    gnutls_strerror(fail));
   fail = 1;
+  }
 else
   *cert = (void *)crt;
 
@@ -74,6 +82,9 @@ gnutls_global_deinit();
 /*****************************************************
 *  Certificate field extraction routines
 *****************************************************/
+
+/* First, some internal service functions */
+
 static uschar *
 g_err(const char * tag, const char * from, int gnutls_err)
 {
@@ -99,7 +110,16 @@ len = strftime(CS cp, 32, "%b %e %T %Y %Z", tp);
 return len > 0 ? cp : NULL;
 }
 
+
 /**/
+/* Now the extractors, called from expand.c
+Arguments:
+  cert		The certificate
+  mod		Optional modifiers for the operator
+
+Return:
+  Allocated string with extracted value
+*/
 
 uschar *
 tls_cert_issuer(void * cert, uschar * mod)
@@ -142,10 +162,12 @@ uschar bin[50], txt[150];
 size_t sz = sizeof(bin);
 uschar * sp;
 uschar * dp;
+int ret;
+
+if ((ret = gnutls_x509_crt_get_serial((gnutls_x509_crt_t)cert,
+    bin, &sz)))
+  return g_err("gs0", __FUNCTION__, ret);
 
-if (gnutls_x509_crt_get_serial((gnutls_x509_crt_t)cert,
-    bin, &sz) || sz > sizeof(bin))
-  return NULL;
 for(dp = txt, sp = bin; sz; dp += 2, sp++, sz--)
   sprintf(dp, "%.2x", *sp);
 for(sp = txt; sp[0]=='0' && sp[1]; ) sp++;	/* leading zeroes */
diff --git a/src/src/tlscert-openssl.c b/src/src/tlscert-openssl.c
index 0614b4025..2411dea9e 100644
--- a/src/src/tlscert-openssl.c
+++ b/src/src/tlscert-openssl.c
@@ -56,12 +56,15 @@ void * reset_point = store_get(0);
 const uschar * cp = string_unprinting(US buf);
 BIO * bp;
 X509 * x;
+int fail = 0;
 
 bp = BIO_new_mem_buf(US cp, -1);
-x = PEM_read_bio_X509(bp, NULL, 0, NULL);
-int fail = 0;
-if (!x)
+if (!(x = PEM_read_bio_X509(bp, NULL, 0, NULL)))
+  {
+  log_write(0, LOG_MAIN, "TLS error in certificate import: %s",
+    ERR_error_string(ERR_get_error(), NULL));
   fail = 1;
+  }
 else
   *cert = (void *)x;
 BIO_free(bp);
@@ -75,9 +78,20 @@ tls_free_cert(void * cert)
 X509_free((X509 *)cert);
 }
 
+
 /*****************************************************
 *  Certificate field extraction routines
 *****************************************************/
+
+/* First, some internal service functions */
+
+static uschar *
+badalloc(void)
+{
+expand_string_message = US"allocation failure";
+return NULL;
+}
+
 static uschar *
 bio_string_copy(BIO * bp, int len)
 {
@@ -105,7 +119,11 @@ static uschar *
 asn1_time_copy(const ASN1_TIME * time, uschar * mod)
 {
 BIO * bp = BIO_new(BIO_s_mem());
-int len = ASN1_TIME_print(bp, time);
+int len;
+
+if (!bp) return badalloc();
+
+len = ASN1_TIME_print(bp, time);
 return mod &&  Ustrcmp(mod, "int") == 0
   ? bio_string_time_to_int(bp, len)
   : bio_string_copy(bp, len);
@@ -115,13 +133,25 @@ static uschar *
 x509_name_copy(X509_NAME * name)
 {
 BIO * bp = BIO_new(BIO_s_mem());
-int len_good =
+int len_good;
+
+if (!bp) return badalloc();
+
+len_good =
   X509_NAME_print_ex(bp, name, 0, XN_FLAG_RFC2253) >= 0
   ? 1 : 0;
 return bio_string_copy(bp, len_good);
 }
 
 /**/
+/* Now the extractors, called from expand.c
+Arguments:
+  cert		The certificate
+  mod		Optional modifiers for the operator
+
+Return:
+  Allocated string with extracted value
+*/
 
 uschar *
 tls_cert_issuer(void * cert, uschar * mod)
@@ -147,8 +177,11 @@ tls_cert_serial_number(void * cert, uschar * mod)
 {
 uschar txt[256];
 BIO * bp = BIO_new(BIO_s_mem());
-int len = i2a_ASN1_INTEGER(bp, X509_get_serialNumber((X509 *)cert));
+int len;
+
+if (!bp) return badalloc();
 
+len = i2a_ASN1_INTEGER(bp, X509_get_serialNumber((X509 *)cert));
 if (len < sizeof(txt))
   BIO_read(bp, txt, len);
 else
@@ -160,8 +193,10 @@ return string_copynlc(txt, len);	/* lowercase */
 uschar *
 tls_cert_signature(void * cert, uschar * mod)
 {
-BIO * bp = BIO_new(BIO_s_mem());
 uschar * cp = NULL;
+BIO * bp = BIO_new(BIO_s_mem());
+
+if (!bp) return badalloc();
 
 if (X509_print_ex(bp, (X509 *)cert, 0,
   X509_FLAG_NO_HEADER | X509_FLAG_NO_VERSION | X509_FLAG_NO_SERIAL | 
@@ -209,6 +244,8 @@ uschar * cp1;
 uschar * cp2;
 uschar * cp3;
 
+if (!bp) return badalloc();
+
 M_ASN1_OCTET_STRING_print(bp, adata);
 /* binary data, DER encoded */
 
-- 
2.25.1