概要

The public API function BIO_new_NDEF is a helper function used for streamingASN.1 data via a BIO. It is primarily used internally to OpenSSL to support theSMIME, CMS and PKCS7 streaming capabilities, but may also be called directly byend user applications.The function receives a BIO from the caller, prepends a new BIO_f_asn1 filterBIO onto the front of it to form a BIO chain, and then returns the new head ofthe BIO chain to the caller. Under certain conditions, for example if a CMSrecipient public key is invalid, the new filter BIO is freed and the functionreturns a NULL result indicating a failure. However, in this case, the BIO chainis not properly cleaned up and the BIO passed by the caller still retainsinternal pointers to the previously freed filter BIO. If the caller then goes onto call BIO_pop() on the BIO then a use-after-free will occur. This will mostlikely result in a crash.This scenario occurs directly in the internal function B64_write_ASN1() whichmay cause BIO_new_NDEF() to be called and will subsequently call BIO_pop() onthe BIO. This internal function is in turn called by the public API functionsPEM_write_bio_ASN1_stream, PEM_write_bio_CMS_stream, PEM_write_bio_PKCS7_stream,SMIME_write_ASN1, SMIME_write_CMS and SMIME_write_PKCS7.Other public API functions that may be impacted by this includei2d_ASN1_bio_stream, BIO_new_CMS, BIO_new_PKCS7, i2d_CMS_bio_stream andi2d_PKCS7_bio_stream.The OpenSSL cms and smime command line applications are similarly affected.

CVSS v3 指标

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