Merge branch 'upstream-curl' into update-curl

* upstream-curl:
  curl 2022-04-27 (1669b17d)

1 files changed, 1409 insertions, 0 deletions

diff --git a/Utilities/cmcurl/lib/vtls/x509asn1.c b/Utilities/cmcurl/lib/vtls/x509asn1.c
new file mode 100644
index 0000000000..f64acb83c9
--- /dev/null
+++ b/Utilities/cmcurl/lib/vtls/x509asn1.c
@@ -0,0 +1,1409 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+
+#include "curl_setup.h"
+
+#if defined(USE_GSKIT) || defined(USE_NSS) || defined(USE_GNUTLS) ||    \
+  defined(USE_WOLFSSL) || defined(USE_SCHANNEL) || defined(USE_SECTRANSP)
+
+#if defined(USE_GSKIT) || defined(USE_WOLFSSL) || defined(USE_SCHANNEL)
+#define WANT_PARSEX509 /* uses Curl_parseX509() */
+#endif
+
+#if defined(USE_GSKIT) || defined(USE_NSS) || defined(USE_GNUTLS) ||    \
+  defined(USE_SCHANNEL) || defined(USE_SECTRANSP)
+#define WANT_EXTRACT_CERTINFO /* uses Curl_extract_certinfo() */
+#define WANT_PARSEX509 /* ... uses Curl_parseX509() */
+#endif
+
+#if defined(USE_GSKIT)
+#define WANT_VERIFYHOST /* uses Curl_verifyhost () */
+#define WANT_PARSEX509 /* ... uses Curl_parseX509() */
+#endif
+
+#include <curl/curl.h>
+#include "urldata.h"
+#include "strcase.h"
+#include "hostcheck.h"
+#include "vtls/vtls.h"
+#include "sendf.h"
+#include "inet_pton.h"
+#include "curl_base64.h"
+#include "x509asn1.h"
+#include "dynbuf.h"
+
+/* The last 3 #include files should be in this order */
+#include "curl_printf.h"
+#include "curl_memory.h"
+#include "memdebug.h"
+
+/*
+ * Constants.
+ */
+
+/* Largest supported ASN.1 structure. */
+#define CURL_ASN1_MAX                   ((size_t) 0x40000)      /* 256K */
+
+/* ASN.1 classes. */
+#define CURL_ASN1_UNIVERSAL             0
+#define CURL_ASN1_APPLICATION           1
+#define CURL_ASN1_CONTEXT_SPECIFIC      2
+#define CURL_ASN1_PRIVATE               3
+
+/* ASN.1 types. */
+#define CURL_ASN1_BOOLEAN               1
+#define CURL_ASN1_INTEGER               2
+#define CURL_ASN1_BIT_STRING            3
+#define CURL_ASN1_OCTET_STRING          4
+#define CURL_ASN1_NULL                  5
+#define CURL_ASN1_OBJECT_IDENTIFIER     6
+#define CURL_ASN1_OBJECT_DESCRIPTOR     7
+#define CURL_ASN1_INSTANCE_OF           8
+#define CURL_ASN1_REAL                  9
+#define CURL_ASN1_ENUMERATED            10
+#define CURL_ASN1_EMBEDDED              11
+#define CURL_ASN1_UTF8_STRING           12
+#define CURL_ASN1_RELATIVE_OID          13
+#define CURL_ASN1_SEQUENCE              16
+#define CURL_ASN1_SET                   17
+#define CURL_ASN1_NUMERIC_STRING        18
+#define CURL_ASN1_PRINTABLE_STRING      19
+#define CURL_ASN1_TELETEX_STRING        20
+#define CURL_ASN1_VIDEOTEX_STRING       21
+#define CURL_ASN1_IA5_STRING            22
+#define CURL_ASN1_UTC_TIME              23
+#define CURL_ASN1_GENERALIZED_TIME      24
+#define CURL_ASN1_GRAPHIC_STRING        25
+#define CURL_ASN1_VISIBLE_STRING        26
+#define CURL_ASN1_GENERAL_STRING        27
+#define CURL_ASN1_UNIVERSAL_STRING      28
+#define CURL_ASN1_CHARACTER_STRING      29
+#define CURL_ASN1_BMP_STRING            30
+
+#ifdef WANT_EXTRACT_CERTINFO
+/* ASN.1 OID table entry. */
+struct Curl_OID {
+  const char *numoid;  /* Dotted-numeric OID. */
+  const char *textoid; /* OID name. */
+};
+
+/* ASN.1 OIDs. */
+static const char       cnOID[] = "2.5.4.3";    /* Common name. */
+static const char       sanOID[] = "2.5.29.17"; /* Subject alternative name. */
+
+static const struct Curl_OID OIDtable[] = {
+  { "1.2.840.10040.4.1",        "dsa" },
+  { "1.2.840.10040.4.3",        "dsa-with-sha1" },
+  { "1.2.840.10045.2.1",        "ecPublicKey" },
+  { "1.2.840.10045.3.0.1",      "c2pnb163v1" },
+  { "1.2.840.10045.4.1",        "ecdsa-with-SHA1" },
+  { "1.2.840.10046.2.1",        "dhpublicnumber" },
+  { "1.2.840.113549.1.1.1",     "rsaEncryption" },
+  { "1.2.840.113549.1.1.2",     "md2WithRSAEncryption" },
+  { "1.2.840.113549.1.1.4",     "md5WithRSAEncryption" },
+  { "1.2.840.113549.1.1.5",     "sha1WithRSAEncryption" },
+  { "1.2.840.113549.1.1.10",    "RSASSA-PSS" },
+  { "1.2.840.113549.1.1.14",    "sha224WithRSAEncryption" },
+  { "1.2.840.113549.1.1.11",    "sha256WithRSAEncryption" },
+  { "1.2.840.113549.1.1.12",    "sha384WithRSAEncryption" },
+  { "1.2.840.113549.1.1.13",    "sha512WithRSAEncryption" },
+  { "1.2.840.113549.2.2",       "md2" },
+  { "1.2.840.113549.2.5",       "md5" },
+  { "1.3.14.3.2.26",            "sha1" },
+  { cnOID,                      "CN" },
+  { "2.5.4.4",                  "SN" },
+  { "2.5.4.5",                  "serialNumber" },
+  { "2.5.4.6",                  "C" },
+  { "2.5.4.7",                  "L" },
+  { "2.5.4.8",                  "ST" },
+  { "2.5.4.9",                  "streetAddress" },
+  { "2.5.4.10",                 "O" },
+  { "2.5.4.11",                 "OU" },
+  { "2.5.4.12",                 "title" },
+  { "2.5.4.13",                 "description" },
+  { "2.5.4.17",                 "postalCode" },
+  { "2.5.4.41",                 "name" },
+  { "2.5.4.42",                 "givenName" },
+  { "2.5.4.43",                 "initials" },
+  { "2.5.4.44",                 "generationQualifier" },
+  { "2.5.4.45",                 "X500UniqueIdentifier" },
+  { "2.5.4.46",                 "dnQualifier" },
+  { "2.5.4.65",                 "pseudonym" },
+  { "1.2.840.113549.1.9.1",     "emailAddress" },
+  { "2.5.4.72",                 "role" },
+  { sanOID,                     "subjectAltName" },
+  { "2.5.29.18",                "issuerAltName" },
+  { "2.5.29.19",                "basicConstraints" },
+  { "2.16.840.1.101.3.4.2.4",   "sha224" },
+  { "2.16.840.1.101.3.4.2.1",   "sha256" },
+  { "2.16.840.1.101.3.4.2.2",   "sha384" },
+  { "2.16.840.1.101.3.4.2.3",   "sha512" },
+  { (const char *) NULL,        (const char *) NULL }
+};
+
+#endif /* WANT_EXTRACT_CERTINFO */
+
+/*
+ * Lightweight ASN.1 parser.
+ * In particular, it does not check for syntactic/lexical errors.
+ * It is intended to support certificate information gathering for SSL backends
+ * that offer a mean to get certificates as a whole, but do not supply
+ * entry points to get particular certificate sub-fields.
+ * Please note there is no pretention here to rewrite a full SSL library.
+ */
+
+static const char *getASN1Element(struct Curl_asn1Element *elem,
+                                  const char *beg, const char *end)
+  WARN_UNUSED_RESULT;
+
+static const char *getASN1Element(struct Curl_asn1Element *elem,
+                                  const char *beg, const char *end)
+{
+  unsigned char b;
+  unsigned long len;
+  struct Curl_asn1Element lelem;
+
+  /* Get a single ASN.1 element into `elem', parse ASN.1 string at `beg'
+     ending at `end'.
+     Returns a pointer in source string after the parsed element, or NULL
+     if an error occurs. */
+  if(!beg || !end || beg >= end || !*beg ||
+     (size_t)(end - beg) > CURL_ASN1_MAX)
+    return NULL;
+
+  /* Process header byte. */
+  elem->header = beg;
+  b = (unsigned char) *beg++;
+  elem->constructed = (b & 0x20) != 0;
+  elem->class = (b >> 6) & 3;
+  b &= 0x1F;
+  if(b == 0x1F)
+    return NULL; /* Long tag values not supported here. */
+  elem->tag = b;
+
+  /* Process length. */
+  if(beg >= end)
+    return NULL;
+  b = (unsigned char) *beg++;
+  if(!(b & 0x80))
+    len = b;
+  else if(!(b &= 0x7F)) {
+    /* Unspecified length. Since we have all the data, we can determine the
+       effective length by skipping element until an end element is found. */
+    if(!elem->constructed)
+      return NULL;
+    elem->beg = beg;
+    while(beg < end && *beg) {
+      beg = getASN1Element(&lelem, beg, end);
+      if(!beg)
+        return NULL;
+    }
+    if(beg >= end)
+      return NULL;
+    elem->end = beg;
+    return beg + 1;
+  }
+  else if((unsigned)b > (size_t)(end - beg))
+    return NULL; /* Does not fit in source. */
+  else {
+    /* Get long length. */
+    len = 0;
+    do {
+      if(len & 0xFF000000L)
+        return NULL;  /* Lengths > 32 bits are not supported. */
+      len = (len << 8) | (unsigned char) *beg++;
+    } while(--b);
+  }
+  if(len > (size_t)(end - beg))
+    return NULL;  /* Element data does not fit in source. */
+  elem->beg = beg;
+  elem->end = beg + len;
+  return elem->end;
+}
+
+#ifdef WANT_EXTRACT_CERTINFO
+
+/*
+ * Search the null terminated OID or OID identifier in local table.
+ * Return the table entry pointer or NULL if not found.
+ */
+static const struct Curl_OID *searchOID(const char *oid)
+{
+  const struct Curl_OID *op;
+  for(op = OIDtable; op->numoid; op++)
+    if(!strcmp(op->numoid, oid) || strcasecompare(op->textoid, oid))
+      return op;
+
+  return NULL;
+}
+
+/*
+ * Convert an ASN.1 Boolean value into its string representation.  Return the
+ * dynamically allocated string, or NULL if source is not an ASN.1 Boolean
+ * value.
+ */
+
+static const char *bool2str(const char *beg, const char *end)
+{
+  if(end - beg != 1)
+    return NULL;
+  return strdup(*beg? "TRUE": "FALSE");
+}
+
+/*
+ * Convert an ASN.1 octet string to a printable string.
+ * Return the dynamically allocated string, or NULL if an error occurs.
+ */
+static const char *octet2str(const char *beg, const char *end)
+{
+  struct dynbuf buf;
+  CURLcode result;
+
+  Curl_dyn_init(&buf, 3 * CURL_ASN1_MAX + 1);
+  result = Curl_dyn_addn(&buf, "", 0);
+
+  while(!result && beg < end)
+    result = Curl_dyn_addf(&buf, "%02x:", (unsigned char) *beg++);
+
+  return Curl_dyn_ptr(&buf);
+}
+
+static const char *bit2str(const char *beg, const char *end)
+{
+  /* Convert an ASN.1 bit string to a printable string.
+     Return the dynamically allocated string, or NULL if an error occurs. */
+
+  if(++beg > end)
+    return NULL;
+  return octet2str(beg, end);
+}
+
+/*
+ * Convert an ASN.1 integer value into its string representation.
+ * Return the dynamically allocated string, or NULL if source is not an
+ * ASN.1 integer value.
+ */
+static const char *int2str(const char *beg, const char *end)
+{
+  unsigned long val = 0;
+  size_t n = end - beg;
+
+  if(!n)
+    return NULL;
+
+  if(n > 4)
+    return octet2str(beg, end);
+
+  /* Represent integers <= 32-bit as a single value. */
+  if(*beg & 0x80)
+    val = ~val;
+
+  do
+    val = (val << 8) | *(const unsigned char *) beg++;
+  while(beg < end);
+  return curl_maprintf("%s%lx", val >= 10? "0x": "", val);
+}
+
+/*
+ * Perform a lazy conversion from an ASN.1 typed string to UTF8. Allocate the
+ * destination buffer dynamically. The allocation size will normally be too
+ * large: this is to avoid buffer overflows.
+ * Terminate the string with a nul byte and return the converted
+ * string length.
+ */
+static ssize_t
+utf8asn1str(char **to, int type, const char *from, const char *end)
+{
+  size_t inlength = end - from;
+  int size = 1;
+  size_t outlength;
+  char *buf;
+
+  *to = NULL;
+  switch(type) {
+  case CURL_ASN1_BMP_STRING:
+    size = 2;
+    break;
+  case CURL_ASN1_UNIVERSAL_STRING:
+    size = 4;
+    break;
+  case CURL_ASN1_NUMERIC_STRING:
+  case CURL_ASN1_PRINTABLE_STRING:
+  case CURL_ASN1_TELETEX_STRING:
+  case CURL_ASN1_IA5_STRING:
+  case CURL_ASN1_VISIBLE_STRING:
+  case CURL_ASN1_UTF8_STRING:
+    break;
+  default:
+    return -1;  /* Conversion not supported. */
+  }
+
+  if(inlength % size)
+    return -1;  /* Length inconsistent with character size. */
+  if(inlength / size > (SIZE_T_MAX - 1) / 4)
+    return -1;  /* Too big. */
+  buf = malloc(4 * (inlength / size) + 1);
+  if(!buf)
+    return -1;  /* Not enough memory. */
+
+  if(type == CURL_ASN1_UTF8_STRING) {
+    /* Just copy. */
+    outlength = inlength;
+    if(outlength)
+      memcpy(buf, from, outlength);
+  }
+  else {
+    for(outlength = 0; from < end;) {
+      int charsize;
+      unsigned int wc;
+
+      wc = 0;
+      switch(size) {
+      case 4:
+        wc = (wc << 8) | *(const unsigned char *) from++;
+        wc = (wc << 8) | *(const unsigned char *) from++;
+        /* FALLTHROUGH */
+      case 2:
+        wc = (wc << 8) | *(const unsigned char *) from++;
+        /* FALLTHROUGH */
+      default: /* case 1: */
+        wc = (wc << 8) | *(const unsigned char *) from++;
+      }
+      charsize = 1;
+      if(wc >= 0x00000080) {
+        if(wc >= 0x00000800) {
+          if(wc >= 0x00010000) {
+            if(wc >= 0x00200000) {
+              free(buf);
+              return -1;        /* Invalid char. size for target encoding. */
+            }
+            buf[outlength + 3] = (char) (0x80 | (wc & 0x3F));
+            wc = (wc >> 6) | 0x00010000;
+            charsize++;
+          }
+          buf[outlength + 2] = (char) (0x80 | (wc & 0x3F));
+          wc = (wc >> 6) | 0x00000800;
+          charsize++;
+        }
+        buf[outlength + 1] = (char) (0x80 | (wc & 0x3F));
+        wc = (wc >> 6) | 0x000000C0;
+        charsize++;
+      }
+      buf[outlength] = (char) wc;
+      outlength += charsize;
+    }
+  }
+  buf[outlength] = '\0';
+  *to = buf;
+  return outlength;
+}
+
+/*
+ * Convert an ASN.1 String into its UTF-8 string representation.
+ * Return the dynamically allocated string, or NULL if an error occurs.
+ */
+static const char *string2str(int type, const char *beg, const char *end)
+{
+  char *buf;
+  if(utf8asn1str(&buf, type, beg, end) < 0)
+    return NULL;
+  return buf;
+}
+
+/*
+ * Decimal ASCII encode unsigned integer `x' into the buflen sized buffer at
+ * buf.  Return the total number of encoded digits, even if larger than
+ * `buflen'.
+ */
+static size_t encodeUint(char *buf, size_t buflen, unsigned int x)
+{
+  size_t i = 0;
+  unsigned int y = x / 10;
+
+  if(y) {
+    i = encodeUint(buf, buflen, y);
+    x -= y * 10;
+  }
+  if(i < buflen)
+    buf[i] = (char) ('0' + x);
+  i++;
+  if(i < buflen)
+    buf[i] = '\0';      /* Store a terminator if possible. */
+  return i;
+}
+
+/*
+ * Convert an ASN.1 OID into its dotted string representation.
+ * Store the result in th `n'-byte buffer at `buf'.
+ * Return the converted string length, or 0 on errors.
+ */
+static size_t encodeOID(char *buf, size_t buflen,
+                        const char *beg, const char *end)
+{
+  size_t i;
+  unsigned int x;
+  unsigned int y;
+
+  /* Process the first two numbers. */
+  y = *(const unsigned char *) beg++;
+  x = y / 40;
+  y -= x * 40;
+  i = encodeUint(buf, buflen, x);
+  if(i < buflen)
+    buf[i] = '.';
+  i++;
+  if(i >= buflen)
+    i += encodeUint(NULL, 0, y);
+  else
+    i += encodeUint(buf + i, buflen - i, y);
+
+  /* Process the trailing numbers. */
+  while(beg < end) {
+    if(i < buflen)
+      buf[i] = '.';
+    i++;
+    x = 0;
+    do {
+      if(x & 0xFF000000)
+        return 0;
+      y = *(const unsigned char *) beg++;
+      x = (x << 7) | (y & 0x7F);
+    } while(y & 0x80);
+    if(i >= buflen)
+      i += encodeUint(NULL, 0, x);
+    else
+      i += encodeUint(buf + i, buflen - i, x);
+  }
+  if(i < buflen)
+    buf[i] = '\0';
+  return i;
+}
+
+/*
+ * Convert an ASN.1 OID into its dotted or symbolic string representation.
+ * Return the dynamically allocated string, or NULL if an error occurs.
+ */
+
+static const char *OID2str(const char *beg, const char *end, bool symbolic)
+{
+  char *buf = NULL;
+  if(beg < end) {
+    size_t buflen = encodeOID(NULL, 0, beg, end);
+    if(buflen) {
+      buf = malloc(buflen + 1); /* one extra for the zero byte */
+      if(buf) {
+        encodeOID(buf, buflen, beg, end);
+        buf[buflen] = '\0';
+
+        if(symbolic) {
+          const struct Curl_OID *op = searchOID(buf);
+          if(op) {
+            free(buf);
+            buf = strdup(op->textoid);
+          }
+        }
+      }
+    }
+  }
+  return buf;
+}
+
+static const char *GTime2str(const char *beg, const char *end)
+{
+  const char *tzp;
+  const char *fracp;
+  char sec1, sec2;
+  size_t fracl;
+  size_t tzl;
+  const char *sep = "";
+
+  /* Convert an ASN.1 Generalized time to a printable string.
+     Return the dynamically allocated string, or NULL if an error occurs. */
+
+  for(fracp = beg; fracp < end && *fracp >= '0' && *fracp <= '9'; fracp++)
+    ;
+
+  /* Get seconds digits. */
+  sec1 = '0';
+  switch(fracp - beg - 12) {
+  case 0:
+    sec2 = '0';
+    break;
+  case 2:
+    sec1 = fracp[-2];
+    /* FALLTHROUGH */
+  case 1:
+    sec2 = fracp[-1];
+    break;
+  default:
+    return NULL;
+  }
+
+  /* Scan for timezone, measure fractional seconds. */
+  tzp = fracp;
+  fracl = 0;
+  if(fracp < end && (*fracp == '.' || *fracp == ',')) {
+    fracp++;
+    do
+      tzp++;
+    while(tzp < end && *tzp >= '0' && *tzp <= '9');
+    /* Strip leading zeroes in fractional seconds. */
+    for(fracl = tzp - fracp - 1; fracl && fracp[fracl - 1] == '0'; fracl--)
+      ;
+  }
+
+  /* Process timezone. */
+  if(tzp >= end)
+    ;           /* Nothing to do. */
+  else if(*tzp == 'Z') {
+    tzp = " GMT";
+    end = tzp + 4;
+  }
+  else {
+    sep = " ";
+    tzp++;
+  }
+
+  tzl = end - tzp;
+  return curl_maprintf("%.4s-%.2s-%.2s %.2s:%.2s:%c%c%s%.*s%s%.*s",
+                       beg, beg + 4, beg + 6,
+                       beg + 8, beg + 10, sec1, sec2,
+                       fracl? ".": "", (int)fracl, fracp,
+                       sep, (int)tzl, tzp);
+}
+
+/*
+ *  Convert an ASN.1 UTC time to a printable string.
+ * Return the dynamically allocated string, or NULL if an error occurs.
+ */
+static const char *UTime2str(const char *beg, const char *end)
+{
+  const char *tzp;
+  size_t tzl;
+  const char *sec;
+
+  for(tzp = beg; tzp < end && *tzp >= '0' && *tzp <= '9'; tzp++)
+    ;
+  /* Get the seconds. */
+  sec = beg + 10;
+  switch(tzp - sec) {
+  case 0:
+    sec = "00";
+  case 2:
+    break;
+  default:
+    return NULL;
+  }
+
+  /* Process timezone. */
+  if(tzp >= end)
+    return NULL;
+  if(*tzp == 'Z') {
+    tzp = "GMT";
+    end = tzp + 3;
+  }
+  else
+    tzp++;
+
+  tzl = end - tzp;
+  return curl_maprintf("%u%.2s-%.2s-%.2s %.2s:%.2s:%.2s %.*s",
+                       20 - (*beg >= '5'), beg, beg + 2, beg + 4,
+                       beg + 6, beg + 8, sec,
+                       (int)tzl, tzp);
+}
+
+/*
+ * Convert an ASN.1 element to a printable string.
+ * Return the dynamically allocated string, or NULL if an error occurs.
+ */
+static const char *ASN1tostr(struct Curl_asn1Element *elem, int type)
+{
+  if(elem->constructed)
+    return NULL; /* No conversion of structured elements. */
+
+  if(!type)
+    type = elem->tag;   /* Type not forced: use element tag as type. */
+
+  switch(type) {
+  case CURL_ASN1_BOOLEAN:
+    return bool2str(elem->beg, elem->end);
+  case CURL_ASN1_INTEGER:
+  case CURL_ASN1_ENUMERATED:
+    return int2str(elem->beg, elem->end);
+  case CURL_ASN1_BIT_STRING:
+    return bit2str(elem->beg, elem->end);
+  case CURL_ASN1_OCTET_STRING:
+    return octet2str(elem->beg, elem->end);
+  case CURL_ASN1_NULL:
+    return strdup("");
+  case CURL_ASN1_OBJECT_IDENTIFIER:
+    return OID2str(elem->beg, elem->end, TRUE);
+  case CURL_ASN1_UTC_TIME:
+    return UTime2str(elem->beg, elem->end);
+  case CURL_ASN1_GENERALIZED_TIME:
+    return GTime2str(elem->beg, elem->end);
+  case CURL_ASN1_UTF8_STRING:
+  case CURL_ASN1_NUMERIC_STRING:
+  case CURL_ASN1_PRINTABLE_STRING:
+  case CURL_ASN1_TELETEX_STRING:
+  case CURL_ASN1_IA5_STRING:
+  case CURL_ASN1_VISIBLE_STRING:
+  case CURL_ASN1_UNIVERSAL_STRING:
+  case CURL_ASN1_BMP_STRING:
+    return string2str(type, elem->beg, elem->end);
+  }
+
+  return NULL;   /* Unsupported. */
+}
+
+/*
+ * ASCII encode distinguished name at `dn' into the `buflen'-sized buffer at
+ * `buf'.
+ *
+ * Returns the total string length, even if larger than `buflen' or -1 on
+ * error.
+ */
+static ssize_t encodeDN(char *buf, size_t buflen, struct Curl_asn1Element *dn)
+{
+  struct Curl_asn1Element rdn;
+  struct Curl_asn1Element atv;
+  struct Curl_asn1Element oid;
+  struct Curl_asn1Element value;
+  size_t l = 0;
+  const char *p1;
+  const char *p2;
+  const char *p3;
+  const char *str;
+
+  for(p1 = dn->beg; p1 < dn->end;) {
+    p1 = getASN1Element(&rdn, p1, dn->end);
+    if(!p1)
+      return -1;
+    for(p2 = rdn.beg; p2 < rdn.end;) {
+      p2 = getASN1Element(&atv, p2, rdn.end);
+      if(!p2)
+        return -1;
+      p3 = getASN1Element(&oid, atv.beg, atv.end);
+      if(!p3)
+        return -1;
+      if(!getASN1Element(&value, p3, atv.end))
+        return -1;
+      str = ASN1tostr(&oid, 0);
+      if(!str)
+        return -1;
+
+      /* Encode delimiter.
+         If attribute has a short uppercase name, delimiter is ", ". */
+      if(l) {
+        for(p3 = str; isupper(*p3); p3++)
+          ;
+        for(p3 = (*p3 || p3 - str > 2)? "/": ", "; *p3; p3++) {
+          if(l < buflen)
+            buf[l] = *p3;
+          l++;
+        }
+      }
+
+      /* Encode attribute name. */
+      for(p3 = str; *p3; p3++) {
+        if(l < buflen)
+          buf[l] = *p3;
+        l++;
+      }
+      free((char *) str);
+
+      /* Generate equal sign. */
+      if(l < buflen)
+        buf[l] = '=';
+      l++;
+
+      /* Generate value. */
+      str = ASN1tostr(&value, 0);
+      if(!str)
+        return -1;
+      for(p3 = str; *p3; p3++) {
+        if(l < buflen)
+          buf[l] = *p3;
+        l++;
+      }
+      free((char *) str);
+    }
+  }
+
+  return l;
+}
+
+#endif /* WANT_EXTRACT_CERTINFO */
+
+#ifdef WANT_PARSEX509
+/*
+ * ASN.1 parse an X509 certificate into structure subfields.
+ * Syntax is assumed to have already been checked by the SSL backend.
+ * See RFC 5280.
+ */
+int Curl_parseX509(struct Curl_X509certificate *cert,
+                   const char *beg, const char *end)
+{
+  struct Curl_asn1Element elem;
+  struct Curl_asn1Element tbsCertificate;
+  const char *ccp;
+  static const char defaultVersion = 0;  /* v1. */
+
+  cert->certificate.header = NULL;
+  cert->certificate.beg = beg;
+  cert->certificate.end = end;
+
+  /* Get the sequence content. */
+  if(!getASN1Element(&elem, beg, end))
+    return -1;  /* Invalid bounds/size. */
+  beg = elem.beg;
+  end = elem.end;
+
+  /* Get tbsCertificate. */
+  beg = getASN1Element(&tbsCertificate, beg, end);
+  if(!beg)
+    return -1;
+  /* Skip the signatureAlgorithm. */
+  beg = getASN1Element(&cert->signatureAlgorithm, beg, end);
+  if(!beg)
+    return -1;
+  /* Get the signatureValue. */
+  if(!getASN1Element(&cert->signature, beg, end))
+    return -1;
+
+  /* Parse TBSCertificate. */
+  beg = tbsCertificate.beg;
+  end = tbsCertificate.end;
+  /* Get optional version, get serialNumber. */
+  cert->version.header = NULL;
+  cert->version.beg = &defaultVersion;
+  cert->version.end = &defaultVersion + sizeof(defaultVersion);
+  beg = getASN1Element(&elem, beg, end);
+  if(!beg)
+    return -1;
+  if(elem.tag == 0) {
+    if(!getASN1Element(&cert->version, elem.beg, elem.end))
+      return -1;
+    beg = getASN1Element(&elem, beg, end);
+    if(!beg)
+      return -1;
+  }
+  cert->serialNumber = elem;
+  /* Get signature algorithm. */
+  beg = getASN1Element(&cert->signatureAlgorithm, beg, end);
+  /* Get issuer. */
+  beg = getASN1Element(&cert->issuer, beg, end);
+  if(!beg)
+    return -1;
+  /* Get notBefore and notAfter. */
+  beg = getASN1Element(&elem, beg, end);
+  if(!beg)
+    return -1;
+  ccp = getASN1Element(&cert->notBefore, elem.beg, elem.end);
+  if(!ccp)
+    return -1;
+  if(!getASN1Element(&cert->notAfter, ccp, elem.end))
+    return -1;
+  /* Get subject. */
+  beg = getASN1Element(&cert->subject, beg, end);
+  if(!beg)
+    return -1;
+  /* Get subjectPublicKeyAlgorithm and subjectPublicKey. */
+  beg = getASN1Element(&cert->subjectPublicKeyInfo, beg, end);
+  if(!beg)
+    return -1;
+  ccp = getASN1Element(&cert->subjectPublicKeyAlgorithm,
+                       cert->subjectPublicKeyInfo.beg,
+                       cert->subjectPublicKeyInfo.end);
+  if(!ccp)
+    return -1;
+  if(!getASN1Element(&cert->subjectPublicKey, ccp,
+                     cert->subjectPublicKeyInfo.end))
+    return -1;
+  /* Get optional issuerUiqueID, subjectUniqueID and extensions. */
+  cert->issuerUniqueID.tag = cert->subjectUniqueID.tag = 0;
+  cert->extensions.tag = elem.tag = 0;
+  cert->issuerUniqueID.header = cert->subjectUniqueID.header = NULL;
+  cert->issuerUniqueID.beg = cert->issuerUniqueID.end = "";
+  cert->subjectUniqueID.beg = cert->subjectUniqueID.end = "";
+  cert->extensions.header = NULL;
+  cert->extensions.beg = cert->extensions.end = "";
+  if(beg < end) {
+    beg = getASN1Element(&elem, beg, end);
+    if(!beg)
+      return -1;
+  }
+  if(elem.tag == 1) {
+    cert->issuerUniqueID = elem;
+    if(beg < end) {
+      beg = getASN1Element(&elem, beg, end);
+      if(!beg)
+        return -1;
+    }
+  }
+  if(elem.tag == 2) {
+    cert->subjectUniqueID = elem;
+    if(beg < end) {
+      beg = getASN1Element(&elem, beg, end);
+      if(!beg)
+        return -1;
+    }
+  }
+  if(elem.tag == 3)
+    if(!getASN1Element(&cert->extensions, elem.beg, elem.end))
+      return -1;
+  return 0;
+}
+
+#endif /* WANT_PARSEX509 */
+
+#ifdef WANT_EXTRACT_CERTINFO
+
+/*
+ * Copy at most 64-characters, terminate with a newline and returns the
+ * effective number of stored characters.
+ */
+static size_t copySubstring(char *to, const char *from)
+{
+  size_t i;
+  for(i = 0; i < 64; i++) {
+    to[i] = *from;
+    if(!*from++)
+      break;
+  }
+
+  to[i++] = '\n';
+  return i;
+}
+
+static const char *dumpAlgo(struct Curl_asn1Element *param,
+                            const char *beg, const char *end)
+{
+  struct Curl_asn1Element oid;
+
+  /* Get algorithm parameters and return algorithm name. */
+
+  beg = getASN1Element(&oid, beg, end);
+  if(!beg)
+    return NULL;
+  param->header = NULL;
+  param->tag = 0;
+  param->beg = param->end = end;
+  if(beg < end)
+    if(!getASN1Element(param, beg, end))
+      return NULL;
+  return OID2str(oid.beg, oid.end, TRUE);
+}
+
+/* return 0 on success, 1 on error */
+static int do_pubkey_field(struct Curl_easy *data, int certnum,
+                           const char *label, struct Curl_asn1Element *elem)
+{
+  const char *output;
+  CURLcode result = CURLE_OK;
+
+  /* Generate a certificate information record for the public key. */
+
+  output = ASN1tostr(elem, 0);
+  if(output) {
+    if(data->set.ssl.certinfo)
+      result = Curl_ssl_push_certinfo(data, certnum, label, output);
+    if(!certnum && !result)
+      infof(data, "   %s: %s", label, output);
+    free((char *) output);
+  }
+  return result ? 1 : 0;
+}
+
+/* return 0 on success, 1 on error */
+static int do_pubkey(struct Curl_easy *data, int certnum,
+                     const char *algo, struct Curl_asn1Element *param,
+                     struct Curl_asn1Element *pubkey)
+{
+  struct Curl_asn1Element elem;
+  struct Curl_asn1Element pk;
+  const char *p;
+
+  /* Generate all information records for the public key. */
+
+  /* Get the public key (single element). */
+  if(!getASN1Element(&pk, pubkey->beg + 1, pubkey->end))
+    return 1;
+
+  if(strcasecompare(algo, "rsaEncryption")) {
+    const char *q;
+    unsigned long len;
+
+    p = getASN1Element(&elem, pk.beg, pk.end);
+    if(!p)
+      return 1;
+
+    /* Compute key length. */
+    for(q = elem.beg; !*q && q < elem.end; q++)
+      ;
+    len = (unsigned long)((elem.end - q) * 8);
+    if(len) {
+      unsigned int i;
+      for(i = *(unsigned char *) q; !(i & 0x80); i <<= 1)
+        len--;
+    }
+    if(len > 32)
+      elem.beg = q;     /* Strip leading zero bytes. */
+    if(!certnum)
+      infof(data, "   RSA Public Key (%lu bits)", len);
+    if(data->set.ssl.certinfo) {
+      q = curl_maprintf("%lu", len);
+      if(q) {
+        CURLcode result =
+          Curl_ssl_push_certinfo(data, certnum, "RSA Public Key", q);
+        free((char *) q);
+        if(result)
+          return 1;
+      }
+    }
+    /* Generate coefficients. */
+    if(do_pubkey_field(data, certnum, "rsa(n)", &elem))
+      return 1;
+    if(!getASN1Element(&elem, p, pk.end))
+      return 1;
+    if(do_pubkey_field(data, certnum, "rsa(e)", &elem))
+      return 1;
+  }
+  else if(strcasecompare(algo, "dsa")) {
+    p = getASN1Element(&elem, param->beg, param->end);
+    if(p) {
+      if(do_pubkey_field(data, certnum, "dsa(p)", &elem))
+        return 1;
+      p = getASN1Element(&elem, p, param->end);
+      if(p) {
+        if(do_pubkey_field(data, certnum, "dsa(q)", &elem))
+          return 1;
+        if(getASN1Element(&elem, p, param->end)) {
+          if(do_pubkey_field(data, certnum, "dsa(g)", &elem))
+            return 1;
+          if(do_pubkey_field(data, certnum, "dsa(pub_key)", &pk))
+            return 1;
+        }
+      }
+    }
+  }
+  else if(strcasecompare(algo, "dhpublicnumber")) {
+    p = getASN1Element(&elem, param->beg, param->end);
+    if(p) {
+      if(do_pubkey_field(data, certnum, "dh(p)", &elem))
+        return 1;
+      if(getASN1Element(&elem, param->beg, param->end)) {
+        if(do_pubkey_field(data, certnum, "dh(g)", &elem))
+          return 1;
+        if(do_pubkey_field(data, certnum, "dh(pub_key)", &pk))
+          return 1;
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+ * Convert an ASN.1 distinguished name into a printable string.
+ * Return the dynamically allocated string, or NULL if an error occurs.
+ */
+static const char *DNtostr(struct Curl_asn1Element *dn)
+{
+  char *buf = NULL;
+  ssize_t buflen = encodeDN(NULL, 0, dn);
+
+  if(buflen >= 0) {
+    buf = malloc(buflen + 1);
+    if(buf) {
+      if(encodeDN(buf, buflen + 1, dn) == -1) {
+        free(buf);
+        return NULL;
+      }
+      buf[buflen] = '\0';
+    }
+  }
+  return buf;
+}
+
+CURLcode Curl_extract_certinfo(struct Curl_easy *data,
+                               int certnum,
+                               const char *beg,
+                               const char *end)
+{
+  struct Curl_X509certificate cert;
+  struct Curl_asn1Element param;
+  const char *ccp;
+  char *cp1;
+  size_t cl1;
+  char *cp2;
+  CURLcode result = CURLE_OK;
+  unsigned long version;
+  size_t i;
+  size_t j;
+
+  if(!data->set.ssl.certinfo)
+    if(certnum)
+      return CURLE_OK;
+
+  /* Prepare the certificate information for curl_easy_getinfo(). */
+
+  /* Extract the certificate ASN.1 elements. */
+  if(Curl_parseX509(&cert, beg, end))
+    return CURLE_PEER_FAILED_VERIFICATION;
+
+  /* Subject. */
+  ccp = DNtostr(&cert.subject);
+  if(!ccp)
+    return CURLE_OUT_OF_MEMORY;
+  if(data->set.ssl.certinfo) {
+    result = Curl_ssl_push_certinfo(data, certnum, "Subject", ccp);
+    if(result)
+      return result;
+  }
+  if(!certnum)
+    infof(data, "%2d Subject: %s", certnum, ccp);
+  free((char *) ccp);
+
+  /* Issuer. */
+  ccp = DNtostr(&cert.issuer);
+  if(!ccp)
+    return CURLE_OUT_OF_MEMORY;
+  if(data->set.ssl.certinfo) {
+    result = Curl_ssl_push_certinfo(data, certnum, "Issuer", ccp);
+  }
+  if(!certnum)
+    infof(data, "   Issuer: %s", ccp);
+  free((char *) ccp);
+  if(result)
+    return result;
+
+  /* Version (always fits in less than 32 bits). */
+  version = 0;
+  for(ccp = cert.version.beg; ccp < cert.version.end; ccp++)
+    version = (version << 8) | *(const unsigned char *) ccp;
+  if(data->set.ssl.certinfo) {
+    ccp = curl_maprintf("%lx", version);
+    if(!ccp)
+      return CURLE_OUT_OF_MEMORY;
+    result = Curl_ssl_push_certinfo(data, certnum, "Version", ccp);
+    free((char *) ccp);
+    if(result)
+      return result;
+  }
+  if(!certnum)
+    infof(data, "   Version: %lu (0x%lx)", version + 1, version);
+
+  /* Serial number. */
+  ccp = ASN1tostr(&cert.serialNumber, 0);
+  if(!ccp)
+    return CURLE_OUT_OF_MEMORY;
+  if(data->set.ssl.certinfo)
+    result = Curl_ssl_push_certinfo(data, certnum, "Serial Number", ccp);
+  if(!certnum)
+    infof(data, "   Serial Number: %s", ccp);
+  free((char *) ccp);
+  if(result)
+    return result;
+
+  /* Signature algorithm .*/
+  ccp = dumpAlgo(&param, cert.signatureAlgorithm.beg,
+                 cert.signatureAlgorithm.end);
+  if(!ccp)
+    return CURLE_OUT_OF_MEMORY;
+  if(data->set.ssl.certinfo)
+    result = Curl_ssl_push_certinfo(data, certnum, "Signature Algorithm", ccp);
+  if(!certnum)
+    infof(data, "   Signature Algorithm: %s", ccp);
+  free((char *) ccp);
+  if(result)
+    return result;
+
+  /* Start Date. */
+  ccp = ASN1tostr(&cert.notBefore, 0);
+  if(!ccp)
+    return CURLE_OUT_OF_MEMORY;
+  if(data->set.ssl.certinfo)
+    result = Curl_ssl_push_certinfo(data, certnum, "Start Date", ccp);
+  if(!certnum)
+    infof(data, "   Start Date: %s", ccp);
+  free((char *) ccp);
+  if(result)
+    return result;
+
+  /* Expire Date. */
+  ccp = ASN1tostr(&cert.notAfter, 0);
+  if(!ccp)
+    return CURLE_OUT_OF_MEMORY;
+  if(data->set.ssl.certinfo)
+    result = Curl_ssl_push_certinfo(data, certnum, "Expire Date", ccp);
+  if(!certnum)
+    infof(data, "   Expire Date: %s", ccp);
+  free((char *) ccp);
+  if(result)
+    return result;
+
+  /* Public Key Algorithm. */
+  ccp = dumpAlgo(&param, cert.subjectPublicKeyAlgorithm.beg,
+                 cert.subjectPublicKeyAlgorithm.end);
+  if(!ccp)
+    return CURLE_OUT_OF_MEMORY;
+  if(data->set.ssl.certinfo)
+    result = Curl_ssl_push_certinfo(data, certnum, "Public Key Algorithm",
+                                    ccp);
+  if(!result) {
+    int ret;
+    if(!certnum)
+      infof(data, "   Public Key Algorithm: %s", ccp);
+    ret = do_pubkey(data, certnum, ccp, &param, &cert.subjectPublicKey);
+    if(ret)
+      result = CURLE_OUT_OF_MEMORY; /* the most likely error */
+  }
+  free((char *) ccp);
+  if(result)
+    return result;
+
+  /* Signature. */
+  ccp = ASN1tostr(&cert.signature, 0);
+  if(!ccp)
+    return CURLE_OUT_OF_MEMORY;
+  if(data->set.ssl.certinfo)
+    result = Curl_ssl_push_certinfo(data, certnum, "Signature", ccp);
+  if(!certnum)
+    infof(data, "   Signature: %s", ccp);
+  free((char *) ccp);
+  if(result)
+    return result;
+
+  /* Generate PEM certificate. */
+  result = Curl_base64_encode(cert.certificate.beg,
+                              cert.certificate.end - cert.certificate.beg,
+                              &cp1, &cl1);
+  if(result)
+    return result;
+  /* Compute the number of characters in final certificate string. Format is:
+     -----BEGIN CERTIFICATE-----\n
+     <max 64 base64 characters>\n
+     .
+     .
+     .
+     -----END CERTIFICATE-----\n
+   */
+  i = 28 + cl1 + (cl1 + 64 - 1) / 64 + 26;
+  cp2 = malloc(i + 1);
+  if(!cp2) {
+    free(cp1);
+    return CURLE_OUT_OF_MEMORY;
+  }
+  /* Build the certificate string. */
+  i = copySubstring(cp2, "-----BEGIN CERTIFICATE-----");
+  for(j = 0; j < cl1; j += 64)
+    i += copySubstring(cp2 + i, cp1 + j);
+  i += copySubstring(cp2 + i, "-----END CERTIFICATE-----");
+  cp2[i] = '\0';
+  free(cp1);
+  if(data->set.ssl.certinfo)
+    result = Curl_ssl_push_certinfo(data, certnum, "Cert", cp2);
+  if(!certnum)
+    infof(data, "%s", cp2);
+  free(cp2);
+  return result;
+}
+
+#endif /* WANT_EXTRACT_CERTINFO */
+
+#endif /* USE_GSKIT or USE_NSS or USE_GNUTLS or USE_WOLFSSL or USE_SCHANNEL
+        * or USE_SECTRANSP */
+
+#ifdef WANT_VERIFYHOST
+
+static const char *checkOID(const char *beg, const char *end,
+                            const char *oid)
+{
+  struct Curl_asn1Element e;
+  const char *ccp;
+  const char *p;
+  bool matched;
+
+  /* Check if first ASN.1 element at `beg' is the given OID.
+     Return a pointer in the source after the OID if found, else NULL. */
+
+  ccp = getASN1Element(&e, beg, end);
+  if(!ccp || e.tag != CURL_ASN1_OBJECT_IDENTIFIER)
+    return NULL;
+
+  p = OID2str(e.beg, e.end, FALSE);
+  if(!p)
+    return NULL;
+
+  matched = !strcmp(p, oid);
+  free((char *) p);
+  return matched? ccp: NULL;
+}
+
+CURLcode Curl_verifyhost(struct Curl_easy *data, struct connectdata *conn,
+                         const char *beg, const char *end)
+{
+  struct Curl_X509certificate cert;
+  struct Curl_asn1Element dn;
+  struct Curl_asn1Element elem;
+  struct Curl_asn1Element ext;
+  struct Curl_asn1Element name;
+  const char *p;
+  const char *q;
+  char *dnsname;
+  int matched = -1;
+  size_t addrlen = (size_t) -1;
+  ssize_t len;
+  const char * const hostname = SSL_HOST_NAME();
+  const char * const dispname = SSL_HOST_DISPNAME();
+  size_t hostlen = strlen(hostname);
+#ifdef ENABLE_IPV6
+  struct in6_addr addr;
+#else
+  struct in_addr addr;
+#endif
+
+  /* Verify that connection server matches info in X509 certificate at
+     `beg'..`end'. */
+
+  if(!SSL_CONN_CONFIG(verifyhost))
+    return CURLE_OK;
+
+  if(Curl_parseX509(&cert, beg, end))
+    return CURLE_PEER_FAILED_VERIFICATION;
+
+  /* Get the server IP address. */
+#ifdef ENABLE_IPV6
+  if(conn->bits.ipv6_ip && Curl_inet_pton(AF_INET6, hostname, &addr))
+    addrlen = sizeof(struct in6_addr);
+  else
+#endif
+  if(Curl_inet_pton(AF_INET, hostname, &addr))
+    addrlen = sizeof(struct in_addr);
+
+  /* Process extensions. */
+  for(p = cert.extensions.beg; p < cert.extensions.end && matched != 1;) {
+    p = getASN1Element(&ext, p, cert.extensions.end);
+    if(!p)
+      return CURLE_PEER_FAILED_VERIFICATION;
+
+    /* Check if extension is a subjectAlternativeName. */
+    ext.beg = checkOID(ext.beg, ext.end, sanOID);
+    if(ext.beg) {
+      ext.beg = getASN1Element(&elem, ext.beg, ext.end);
+      if(!ext.beg)
+        return CURLE_PEER_FAILED_VERIFICATION;
+      /* Skip critical if present. */
+      if(elem.tag == CURL_ASN1_BOOLEAN) {
+        ext.beg = getASN1Element(&elem, ext.beg, ext.end);
+        if(!ext.beg)
+          return CURLE_PEER_FAILED_VERIFICATION;
+      }
+      /* Parse the octet string contents: is a single sequence. */
+      if(!getASN1Element(&elem, elem.beg, elem.end))
+        return CURLE_PEER_FAILED_VERIFICATION;
+      /* Check all GeneralNames. */
+      for(q = elem.beg; matched != 1 && q < elem.end;) {
+        q = getASN1Element(&name, q, elem.end);
+        if(!q)
+          break;
+        switch(name.tag) {
+        case 2: /* DNS name. */
+          len = utf8asn1str(&dnsname, CURL_ASN1_IA5_STRING,
+                            name.beg, name.end);
+          if(len > 0 && (size_t)len == strlen(dnsname))
+            matched = Curl_cert_hostcheck(dnsname,
+                                          (size_t)len, hostname, hostlen);
+          else
+            matched = 0;
+          free(dnsname);
+          break;
+
+        case 7: /* IP address. */
+          matched = (size_t) (name.end - name.beg) == addrlen &&
+                    !memcmp(&addr, name.beg, addrlen);
+          break;
+        }
+      }
+    }
+  }
+
+  switch(matched) {
+  case 1:
+    /* an alternative name matched the server hostname */
+    infof(data, "  subjectAltName: %s matched", dispname);
+    return CURLE_OK;
+  case 0:
+    /* an alternative name field existed, but didn't match and then
+       we MUST fail */
+    infof(data, "  subjectAltName does not match %s", dispname);
+    return CURLE_PEER_FAILED_VERIFICATION;
+  }
+
+  /* Process subject. */
+  name.header = NULL;
+  name.beg = name.end = "";
+  q = cert.subject.beg;
+  /* we have to look to the last occurrence of a commonName in the
+     distinguished one to get the most significant one. */
+  while(q < cert.subject.end) {
+    q = getASN1Element(&dn, q, cert.subject.end);
+    if(!q)
+      break;
+    for(p = dn.beg; p < dn.end;) {
+      p = getASN1Element(&elem, p, dn.end);
+      if(!p)
+        return CURLE_PEER_FAILED_VERIFICATION;
+      /* We have a DN's AttributeTypeAndValue: check it in case it's a CN. */
+      elem.beg = checkOID(elem.beg, elem.end, cnOID);
+      if(elem.beg)
+        name = elem;    /* Latch CN. */
+    }
+  }
+
+  /* Check the CN if found. */
+  if(!getASN1Element(&elem, name.beg, name.end))
+    failf(data, "SSL: unable to obtain common name from peer certificate");
+  else {
+    len = utf8asn1str(&dnsname, elem.tag, elem.beg, elem.end);
+    if(len < 0) {
+      free(dnsname);
+      return CURLE_OUT_OF_MEMORY;
+    }
+    if(strlen(dnsname) != (size_t) len)         /* Nul byte in string ? */
+      failf(data, "SSL: illegal cert name field");
+    else if(Curl_cert_hostcheck((const char *) dnsname,
+                                len, hostname, hostlen)) {
+      infof(data, "  common name: %s (matched)", dnsname);
+      free(dnsname);
+      return CURLE_OK;
+    }
+    else
+      failf(data, "SSL: certificate subject name '%s' does not match "
+            "target host name '%s'", dnsname, dispname);
+    free(dnsname);
+  }
+
+  return CURLE_PEER_FAILED_VERIFICATION;
+}
+
+#endif /* WANT_VERIFYHOST */