libssl3t64: ASN.1 strings are represented internally within OpenSSL as an ASN1_STRINGstructure which contains a buffer holding th...

ASN.1 strings are represented internally within OpenSSL as an ASN1_STRINGstructure which contains a buffer holding the string data and a fieldholding the buffer length. This contrasts with normal C strings which arerepesented as a buffer for the string data which is terminated with a NUL(0) byte. Although not a strict requirement, ASN.1 strings that are parsedusing OpenSSL's own "d2i" functions (and other similar parsing functions)as well as any string whose value has been set with the ASN1_STRING_set()function will additionally NUL terminate the byte array in the ASN1_STRINGstructure. However, it is possible for applications to directly constructvalid ASN1_STRING structures which do not NUL terminate the byte array bydirectly setting the "data" and "length" fields in the ASN1_STRING array.This can also happen by using the ASN1_STRING_set0() function. NumerousOpenSSL functions that print ASN.1 data have been found to assume that theASN1_STRING byte array will be NUL terminated, even though this is notguaranteed for strings that have been directly constructed. Where anapplication requests an ASN.1 structure to be printed, and where that ASN.1structure contains ASN1_STRINGs that have been directly constructed by theapplication without NUL terminating the "data" field, then a read bufferoverrun can occur. The same thing can also occur during name constraintsprocessing of certificates (for example if a certificate has been directlyconstructed by the application instead of loading it via the OpenSSLparsing functions, and the certificate contains non NUL terminatedASN1_STRING structures). It can also occur in the X509_get1_email(),X509_REQ_get1_email() and X509_get1_ocsp() functions. If a malicious actorcan cause an application to directly construct an ASN1_STRING and thenprocess it through one of the affected OpenSSL functions then this issuecould be hit. This might result in a crash (causing a Denial of Serviceattack). It could also result in the disclosure of private memory contents(such as private keys, or sensitive plaintext). Fixed in OpenSSL 1.1.1l(Affected 1.1.1-1.1.1k). Fixed in OpenSSL 1.0.2za (Affected 1.0.2-1.0.2y).

Where it's fixed