Description

Crypt::OpenSSL::PKCS12 versions before 1.98 for Perl allow a NULL pointer dereference in print_attribute via a zero length BMPSTRING attribute. print_attribute() sizes the destination buffer for a BMPSTRING attribute from its declared byte length with Renew(*attribute, length, char). A zero length attribute makes that a zero size reallocation, which Perl implements as a free returning NULL, so the buffer pointer becomes NULL, the following strncpy copies nothing, and the caller dereferences NULL in the strlen() it passes to newSVpvn(). A zero length BMPSTRING is even length, so the ASN.1 decoder accepts it and the value reaches this code. The UTF8STRING, OCTET STRING and BIT STRING arms size on length + 1 or length * 4 + 1 and are unaffected. Any caller that passes an untrusted PKCS#12 file to info_as_hash() can crash the process. info() prints attribute values directly without sizing a buffer and is unaffected.

Mitigation

Aliases