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authorPatrick Monnerat <patrick@monnerat.net>2016-11-24 14:28:39 +0100
committerPatrick Monnerat <patrick@monnerat.net>2016-11-24 14:28:39 +0100
commit945f60e8a7f08aedb0eede5e3574f1972fc86ec8 (patch)
tree6a3479b7bdaf88a17f4f915846c1fddaff73873a /lib
parent3e9c0230f45cafb9154bb4fcdc8ff2b51f00701a (diff)
Limit ASN.1 structure sizes to 256K. Prevent some allocation size overflows.
See CRL-01-006.
Diffstat (limited to 'lib')
-rw-r--r--lib/vauth/cleartext.c24
-rw-r--r--lib/vtls/cyassl.c3
-rw-r--r--lib/vtls/gskit.c3
-rw-r--r--lib/x509asn1.c33
-rw-r--r--lib/x509asn1.h9
5 files changed, 47 insertions, 25 deletions
diff --git a/lib/vauth/cleartext.c b/lib/vauth/cleartext.c
index 6df419a64..a761ae784 100644
--- a/lib/vauth/cleartext.c
+++ b/lib/vauth/cleartext.c
@@ -66,16 +66,27 @@ CURLcode Curl_auth_create_plain_message(struct Curl_easy *data,
char *plainauth;
size_t ulen;
size_t plen;
+ size_t plainlen;
+ *outlen = 0;
+ *outptr = NULL;
ulen = strlen(userp);
plen = strlen(passwdp);
- plainauth = malloc(2 * ulen + plen + 2);
- if(!plainauth) {
- *outlen = 0;
- *outptr = NULL;
+ /* Compute binary message length, checking for overflows. */
+ plainlen = 2 * ulen;
+ if(plainlen < ulen)
+ return CURLE_OUT_OF_MEMORY;
+ plainlen += plen;
+ if(plainlen < plen)
+ return CURLE_OUT_OF_MEMORY;
+ plainlen += 2;
+ if(plainlen < 2)
+ return CURLE_OUT_OF_MEMORY;
+
+ plainauth = malloc(plainlen);
+ if(!plainauth)
return CURLE_OUT_OF_MEMORY;
- }
/* Calculate the reply */
memcpy(plainauth, userp, ulen);
@@ -85,8 +96,7 @@ CURLcode Curl_auth_create_plain_message(struct Curl_easy *data,
memcpy(plainauth + 2 * ulen + 2, passwdp, plen);
/* Base64 encode the reply */
- result = Curl_base64_encode(data, plainauth, 2 * ulen + plen + 2, outptr,
- outlen);
+ result = Curl_base64_encode(data, plainauth, plainlen, outptr, outlen);
free(plainauth);
return result;
diff --git a/lib/vtls/cyassl.c b/lib/vtls/cyassl.c
index 39248d2c7..f0c0f4a07 100644
--- a/lib/vtls/cyassl.c
+++ b/lib/vtls/cyassl.c
@@ -512,7 +512,8 @@ cyassl_connect_step2(struct connectdata *conn,
}
memset(&x509_parsed, 0, sizeof x509_parsed);
- Curl_parseX509(&x509_parsed, x509_der, x509_der + x509_der_len);
+ if(Curl_parseX509(&x509_parsed, x509_der, x509_der + x509_der_len))
+ return CURLE_SSL_PINNEDPUBKEYNOTMATCH;
pubkey = &x509_parsed.subjectPublicKeyInfo;
if(!pubkey->header || pubkey->end <= pubkey->header) {
diff --git a/lib/vtls/gskit.c b/lib/vtls/gskit.c
index e1dd9b6b0..2ccb9e47b 100644
--- a/lib/vtls/gskit.c
+++ b/lib/vtls/gskit.c
@@ -875,9 +875,8 @@ static CURLcode gskit_connect_step3(struct connectdata *conn, int sockindex)
curl_X509certificate x509;
curl_asn1Element *p;
- if(!cert)
+ if(Curl_parseX509(&x509, cert, certend))
return CURLE_SSL_PINNEDPUBKEYNOTMATCH;
- Curl_parseX509(&x509, cert, certend);
p = &x509.subjectPublicKeyInfo;
result = Curl_pin_peer_pubkey(data, ptr, p->header, p->end - p->header);
if(result) {
diff --git a/lib/x509asn1.c b/lib/x509asn1.c
index 74a511b2d..dc8aa81f3 100644
--- a/lib/x509asn1.c
+++ b/lib/x509asn1.c
@@ -40,6 +40,9 @@
#include "curl_memory.h"
#include "memdebug.h"
+/* For overflow checks. */
+#define CURL_SIZE_T_MAX ((size_t) ~0)
+
/* ASN.1 OIDs. */
static const char cnOID[] = "2.5.4.3"; /* Common name. */
@@ -117,7 +120,7 @@ const char * Curl_getASN1Element(curl_asn1Element * elem,
Returns a pointer in source string after the parsed element, or NULL
if an error occurs. */
- if(beg >= end || !*beg)
+ if(!beg || !end || (size_t) (end - beg) > CURL_ASN1_MAX)
return (const char *) NULL;
/* Process header byte. */
@@ -198,15 +201,17 @@ static const char * bool2str(const char * beg, const char * end)
static const char * octet2str(const char * beg, const char * end)
{
size_t n = end - beg;
- char * buf;
+ char * buf = NULL;
/* Convert an ASN.1 octet string to a printable string.
Return the dynamically allocated string, or NULL if an error occurs. */
- buf = malloc(3 * n + 1);
- if(buf)
- for(n = 0; beg < end; n += 3)
- snprintf(buf + n, 4, "%02x:", *(const unsigned char *) beg++);
+ if(n <= (CURL_SIZE_T_MAX - 1) / 3) {
+ buf = malloc(3 * n + 1);
+ if(buf)
+ for(n = 0; beg < end; n += 3)
+ snprintf(buf + n, 4, "%02x:", *(const unsigned char *) beg++);
+ }
return buf;
}
@@ -282,6 +287,8 @@ utf8asn1str(char * * to, int type, const char * from, const char * end)
if(inlength % size)
return -1; /* Length inconsistent with character size. */
+ if(inlength / size > (CURL_SIZE_T_MAX - 1) / 4)
+ return -1; /* Too big. */
buf = malloc(4 * (inlength / size) + 1);
if(!buf)
return -1; /* Not enough memory. */
@@ -669,8 +676,8 @@ const char * Curl_DNtostr(curl_asn1Element * dn)
* X509 parser.
*/
-void Curl_parseX509(curl_X509certificate * cert,
- const char * beg, const char * end)
+int Curl_parseX509(curl_X509certificate * cert,
+ const char * beg, const char * end)
{
curl_asn1Element elem;
curl_asn1Element tbsCertificate;
@@ -686,7 +693,8 @@ void Curl_parseX509(curl_X509certificate * cert,
cert->certificate.end = end;
/* Get the sequence content. */
- Curl_getASN1Element(&elem, beg, end);
+ if(!Curl_getASN1Element(&elem, beg, end))
+ return -1; /* Invalid bounds/size. */
beg = elem.beg;
end = elem.end;
@@ -749,6 +757,7 @@ void Curl_parseX509(curl_X509certificate * cert,
}
if(elem.tag == 3)
Curl_getASN1Element(&cert->extensions, elem.beg, elem.end);
+ return 0;
}
static size_t copySubstring(char * to, const char * from)
@@ -889,7 +898,8 @@ CURLcode Curl_extract_certinfo(struct connectdata * conn,
/* Prepare the certificate information for curl_easy_getinfo(). */
/* Extract the certificate ASN.1 elements. */
- Curl_parseX509(&cert, beg, end);
+ if(Curl_parseX509(&cert, beg, end))
+ return CURLE_OUT_OF_MEMORY;
/* Subject. */
ccp = Curl_DNtostr(&cert.subject);
@@ -1080,9 +1090,8 @@ CURLcode Curl_verifyhost(struct connectdata * conn,
if(!data->set.ssl.verifyhost)
return CURLE_OK;
- if(!beg)
+ if(Curl_parseX509(&cert, beg, end))
return CURLE_PEER_FAILED_VERIFICATION;
- Curl_parseX509(&cert, beg, end);
/* Get the server IP address. */
#ifdef ENABLE_IPV6
diff --git a/lib/x509asn1.h b/lib/x509asn1.h
index 0f2b9304f..f5c88e8e0 100644
--- a/lib/x509asn1.h
+++ b/lib/x509asn1.h
@@ -8,7 +8,7 @@
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
- * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2016, 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
@@ -34,6 +34,9 @@
* 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
@@ -121,8 +124,8 @@ const char * Curl_getASN1Element(curl_asn1Element * elem,
const char * beg, const char * end);
const char * Curl_ASN1tostr(curl_asn1Element * elem, int type);
const char * Curl_DNtostr(curl_asn1Element * dn);
-void Curl_parseX509(curl_X509certificate * cert,
- const char * beg, const char * end);
+int Curl_parseX509(curl_X509certificate * cert,
+ const char * beg, const char * end);
CURLcode Curl_extract_certinfo(struct connectdata * conn, int certnum,
const char * beg, const char * end);
CURLcode Curl_verifyhost(struct connectdata * conn,