git: c40b21a7e2a0 - stable/11 - openssl: Fix a read buffer overrun in X509_CERT_AUX_print()

[Ed Maste]

The branch stable/11 has been updated by emaste:

URL: https://cgit.FreeBSD.org/src/commit/?id=c40b21a7e2a030434d6850c28a4217c46b33577b

commit c40b21a7e2a030434d6850c28a4217c46b33577b
Author:     Matt Caswell <matt at openssl.org>
AuthorDate: 2021-08-17 13:41:48 +0000
Commit:     Ed Maste <emaste at FreeBSD.org>
CommitDate: 2021-08-31 16:25:09 +0000

    openssl: Fix a read buffer overrun in X509_CERT_AUX_print()
    
    This is a backport of commit c5dc9ab965f to 1.0.2. That commit fixed
    the same bug but in master/1.1.1 it is in the function X509_aux_print().
    The original commit had the following description:
    
    Fix a read buffer overrun in X509_aux_print().
    
    The ASN1_STRING_get0_data(3) manual explitely cautions the reader
    that the data is not necessarily NUL-terminated, and the function
    X509_alias_set1(3) does not sanitize the data passed into it in any
    way either, so we must assume the return value from X509_alias_get0(3)
    is merely a byte array and not necessarily a string in the sense
    of the C language.
    
    I found this bug while writing manual pages for X509_print_ex(3)
    and related functions.  Theo Buehler <tb at openbsd.org> checked my
    patch to fix the same bug in LibreSSL, see
    
    http://cvsweb.openbsd.org/src/lib/libcrypto/asn1/t_x509a.c#rev1.9
    
    As an aside, note that the function still produces incomplete and
    misleading results when the data contains a NUL byte in the middle
    and that error handling is consistently absent throughout, even
    though the function provides an "int" return value obviously intended
    to be 1 for success and 0 for failure, and even though this function
    is called by another function that also wants to return 1 for success
    and 0 for failure and even does so in many of its code paths, though
    not in others.  But let's stay focussed.  Many things would be nice
    to have in the wide wild world, but a buffer overflow must not be
    allowed to remain in our backyard.
    
    CVE-2021-3712
    
    Reviewed-by: Paul Dale <pauli at openssl.org>
---
 crypto/openssl/crypto/asn1/t_x509a.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/crypto/openssl/crypto/asn1/t_x509a.c b/crypto/openssl/crypto/asn1/t_x509a.c
index d1b897a469fd..b1bc9d0cd28b 100644
--- a/crypto/openssl/crypto/asn1/t_x509a.c
+++ b/crypto/openssl/crypto/asn1/t_x509a.c
@@ -104,7 +104,8 @@ int X509_CERT_AUX_print(BIO *out, X509_CERT_AUX *aux, int indent)
     } else
         BIO_printf(out, "%*sNo Rejected Uses.\n", indent, "");
     if (aux->alias)
-        BIO_printf(out, "%*sAlias: %s\n", indent, "", aux->alias->data);
+        BIO_printf(out, "%*sAlias: %.*s\n", indent, "", aux->alias->length,
+                   aux->alias->data);
     if (aux->keyid) {
         BIO_printf(out, "%*sKey Id: ", indent, "");
         for (i = 0; i < aux->keyid->length; i++)