Requests an ASN.1 structure to be printed, and where that ASN.1 structureĬontains ASN1_STRINGs that have been directly constructed by the application Guaranteed for strings that have been directly constructed. The ASN1_STRING byte array will be NUL terminated, even though this is not Numerous OpenSSL functions that print ASN.1 data have been found to assume that "data" and "length" fields in the ASN1_STRING array. Structures which do not NUL terminate the byte array by directly setting the However, it is possible for applications to directly construct valid ASN1_STRING NUL terminate the byte array in the ASN1_STRING structure. Whose value has been set with the ASN1_STRING_set() function will additionally Own "d2i" functions (and other similar parsing functions) as well as any string This contrasts with normal C strings which are repesented asĪ buffer for the string data which is terminated with a NUL (0) byte.Īlthough not a strict requirement, ASN.1 strings that are parsed using OpenSSL's Structure which contains a buffer holding the string data and a field holding Read buffer overruns processing ASN.1 strings (CVE-2021-3712)ĪSN.1 strings are represented internally within OpenSSL as an ASN1_STRING This issue was reported to OpenSSL on 12th August 2021 by John Ouyang. OpenSSL 3.0 alpha/beta releases are also affected but this issue will be OpenSSL 1.0.2 is not impacted by this issue.
#Openssl decryption upgrade#
Versions should upgrade to OpenSSL 1.1.1l. OpenSSL versions 1.1.1k and below are affected by this issue. The location of the buffer is application dependent but is typically Maximum of 62 bytes altering the contents of other data held after theīuffer, possibly changing application behaviour or causing the application toĬrash. This can lead to a buffer overflow when EVP_PKEY_decrypt() isĬalled by the application a second time with a buffer that is too small.Ī malicious attacker who is able present SM2 content for decryption to anĪpplication could cause attacker chosen data to overflow the buffer by up to a
#Openssl decryption code#
Sized buffer and call EVP_PKEY_decrypt() again, but this time passing a non-NULLĪ bug in the implementation of the SM2 decryption code means that theĬalculation of the buffer size required to hold the plaintext returned by theįirst call to EVP_PKEY_decrypt() can be smaller than the actual size required by The application can then allocate a sufficiently On exit, the "outlen" parameter is populated with the buffer size required to
![openssl decryption openssl decryption](https://i1.wp.com/thelinuxcode.com/wp-content/uploads/2018/03/Selection_067.png)
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The first time, on entry, the "out" parameter can be NULL and, Typically an application will call thisįunction twice. In order to decrypt SM2 encrypted data an application is expected to call theĪPI function EVP_PKEY_decrypt(). SM2 Decryption Buffer Overflow (CVE-2021-3711) Overruns processing ASN.1 strings (CVE-2021-3712) To: OpenSSL SM2 Decryption Buffer Overflow (CVE-2021-3711), Read buffer Follow on Twitter for new release announcements and other news