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From 1648afef33c1d97fb203c82291b8a61269e85d3b Mon Sep 17 00:00:00 2001
From: Kazuki Yamaguchi <k@rhe.jp>
Date: Mon, 19 Sep 2016 15:38:44 +0900
Subject: [PATCH] asn1: fix out-of-bounds read in decoding constructed objects
OpenSSL::ASN1.{decode,decode_all,traverse} have a bug of out-of-bounds
read. int_ossl_asn1_decode0_cons() does not give the correct available
length to ossl_asn1_decode() when decoding the inner components of a
constructed object. This can cause out-of-bounds read if a crafted input
given.
Reference: https://hackerone.com/reports/170316
Upstream-Status: Backport
CVE: CVE-2017-14033
Signed-off-by: Rajkumar Veer<rveer@mvista.com>
---
ext/openssl/ossl_asn1.c | 13 ++++++-------
test/test_asn1.rb | 23 +++++++++++++++++++++++
2 files changed, 29 insertions(+), 7 deletions(-)
--- a/ext/openssl/ossl_asn1.c
+++ b/ext/openssl/ossl_asn1.c
@@ -871,19 +871,18 @@
{
VALUE value, asn1data, ary;
int infinite;
- long off = *offset;
+ long available_len, off = *offset;
infinite = (j == 0x21);
ary = rb_ary_new();
- while (length > 0 || infinite) {
+ available_len = infinite ? max_len : length;
+ while (available_len > 0 ) {
long inner_read = 0;
- value = ossl_asn1_decode0(pp, max_len, &off, depth + 1, yield, &inner_read);
+ value = ossl_asn1_decode0(pp, available_len, &off, depth + 1, yield, &inner_read);
*num_read += inner_read;
- max_len -= inner_read;
+ available_len -= inner_read;
rb_ary_push(ary, value);
- if (length > 0)
- length -= inner_read;
if (infinite &&
NUM2INT(ossl_asn1_get_tag(value)) == V_ASN1_EOC &&
@@ -974,7 +973,7 @@
if(j & V_ASN1_CONSTRUCTED) {
*pp += hlen;
off += hlen;
- asn1data = int_ossl_asn1_decode0_cons(pp, length, len, &off, depth, yield, j, tag, tag_class, &inner_read);
+ asn1data = int_ossl_asn1_decode0_cons(pp, length - hlen, len, &off, depth, yield, j, tag, tag_class, &inner_read);
inner_read += hlen;
}
else {
--- a/test/openssl/test_asn1.rb
+++ b/test/openssl/test_asn1.rb
@@ -595,6 +595,29 @@
assert_equal(false, asn1.value[3].infinite_length)
end
+ def test_decode_constructed_overread
+ test = %w{ 31 06 31 02 30 02 05 00 }
+ # ^ <- invalid
+ raw = [test.join].pack("H*")
+ ret = []
+ assert_raise(OpenSSL::ASN1::ASN1Error) {
+ OpenSSL::ASN1.traverse(raw) { |x| ret << x }
+ }
+ assert_equal 2, ret.size
+ assert_equal 17, ret[0][6]
+ assert_equal 17, ret[1][6]
+
+ test = %w{ 31 80 30 03 00 00 }
+ # ^ <- invalid
+ raw = [test.join].pack("H*")
+ ret = []
+ assert_raise(OpenSSL::ASN1::ASN1Error) {
+ OpenSSL::ASN1.traverse(raw) { |x| ret << x }
+ }
+ assert_equal 1, ret.size
+ assert_equal 17, ret[0][6]
+ end
+
private
def assert_universal(tag, asn1)
|
