From 970b5f67512e00fb26765a14b4a1cb8a8a04276d Mon Sep 17 00:00:00 2001
From: Laszlo Ersek <lersek@redhat.com>
Date: Mon, 2 Dec 2019 12:31:57 +0100
Subject: [PATCH 6/9] CryptoPkg/TlsLib: TlsSetVerifyHost: parse IP address
 literals as such (CVE-2019-14553)
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RH-Author: Laszlo Ersek <lersek@redhat.com>
Message-id: <20191117220052.15700-7-lersek@redhat.com>
Patchwork-id: 92452
O-Subject: [RHEL-8.2.0 edk2 PATCH 6/9] CryptoPkg/TlsLib: TlsSetVerifyHost: parse IP address literals as such (CVE-2019-14553)
Bugzilla: 1536624
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
RH-Acked-by: Vitaly Kuznetsov <vkuznets@redhat.com>

Using the inet_pton() function that we imported in the previous patches,
recognize if "HostName" is an IP address literal, and then parse it into
binary representation. Passing the latter to OpenSSL for server
certificate validation is important, per RFC-2818
<https://tools.ietf.org/html/rfc2818#section-3.1>:

> In some cases, the URI is specified as an IP address rather than a
> hostname. In this case, the iPAddress subjectAltName must be present in
> the certificate and must exactly match the IP in the URI.

Note: we cannot use X509_VERIFY_PARAM_set1_ip_asc() because in the OpenSSL
version that is currently consumed by edk2, said function depends on
sscanf() for parsing IPv4 literals. In
"CryptoPkg/Library/BaseCryptLib/SysCall/CrtWrapper.c", we only provide an
empty -- always failing -- stub for sscanf(), however.

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Jiaxin Wu <jiaxin.wu@intel.com>
Cc: Sivaraman Nainar <sivaramann@amiindia.co.in>
Cc: Xiaoyu Lu <xiaoyux.lu@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=960
CVE: CVE-2019-14553
Suggested-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Acked-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Jiaxin Wu <jiaxin.wu@intel.com>
(cherry picked from commit 1e72b1fb2ec597caedb5170079bb213f6d67f32a)
---
 CryptoPkg/Library/TlsLib/TlsConfig.c | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/CryptoPkg/Library/TlsLib/TlsConfig.c b/CryptoPkg/Library/TlsLib/TlsConfig.c
index 2bf5aee..307eb57 100644
--- a/CryptoPkg/Library/TlsLib/TlsConfig.c
+++ b/CryptoPkg/Library/TlsLib/TlsConfig.c
@@ -517,7 +517,11 @@ TlsSetVerifyHost (
   IN     CHAR8                    *HostName
   )
 {
-  TLS_CONNECTION  *TlsConn;
+  TLS_CONNECTION    *TlsConn;
+  X509_VERIFY_PARAM *VerifyParam;
+  UINTN             BinaryAddressSize;
+  UINT8             BinaryAddress[MAX (NS_INADDRSZ, NS_IN6ADDRSZ)];
+  INTN              ParamStatus;
 
   TlsConn = (TLS_CONNECTION *) Tls;
   if (TlsConn == NULL || TlsConn->Ssl == NULL || HostName == NULL) {
@@ -526,11 +530,27 @@ TlsSetVerifyHost (
 
   SSL_set_hostflags(TlsConn->Ssl, Flags);
 
-  if (SSL_set1_host(TlsConn->Ssl, HostName) == 0) {
-    return EFI_ABORTED;
+  VerifyParam = SSL_get0_param (TlsConn->Ssl);
+  ASSERT (VerifyParam != NULL);
+
+  BinaryAddressSize = 0;
+  if (inet_pton (AF_INET6, HostName, BinaryAddress) == 1) {
+    BinaryAddressSize = NS_IN6ADDRSZ;
+  } else if (inet_pton (AF_INET, HostName, BinaryAddress) == 1) {
+    BinaryAddressSize = NS_INADDRSZ;
   }
 
-  return EFI_SUCCESS;
+  if (BinaryAddressSize > 0) {
+    DEBUG ((DEBUG_VERBOSE, "%a:%a: parsed \"%a\" as an IPv%c address "
+      "literal\n", gEfiCallerBaseName, __FUNCTION__, HostName,
+      (UINTN)((BinaryAddressSize == NS_IN6ADDRSZ) ? '6' : '4')));
+    ParamStatus = X509_VERIFY_PARAM_set1_ip (VerifyParam, BinaryAddress,
+                    BinaryAddressSize);
+  } else {
+    ParamStatus = X509_VERIFY_PARAM_set1_host (VerifyParam, HostName, 0);
+  }
+
+  return (ParamStatus == 1) ? EFI_SUCCESS : EFI_ABORTED;
 }
 
 /**
-- 
1.8.3.1