openssl: Update to 1.1.1l.

Changes between 1.1.1k and 1.1.1l [24 Aug 2021]

*) Fixed an SM2 Decryption Buffer Overflow.

  In order to decrypt SM2 encrypted data an application is expected to call the
  API function EVP_PKEY_decrypt(). Typically an application will call this
  function twice. The first time, on entry, the "out" parameter can be NULL and,
  on exit, the "outlen" parameter is populated with the buffer size required to
  hold the decrypted plaintext. The application can then allocate a sufficiently
  sized buffer and call EVP_PKEY_decrypt() again, but this time passing a non-NULL
  value for the "out" parameter.

  A bug in the implementation of the SM2 decryption code means that the
  calculation of the buffer size required to hold the plaintext returned by the
  first call to EVP_PKEY_decrypt() can be smaller than the actual size required by
  the second call. This can lead to a buffer overflow when EVP_PKEY_decrypt() is
  called by the application a second time with a buffer that is too small.

  A malicious attacker who is able present SM2 content for decryption to an
  application could cause attacker chosen data to overflow the buffer by up to a
  maximum of 62 bytes altering the contents of other data held after the
  buffer, possibly changing application behaviour or causing the application to
  crash. The location of the buffer is application dependent but is typically
  heap allocated.
  (CVE-2021-3711)
  [Matt Caswell]

*) Fixed various read buffer overruns processing ASN.1 strings

  ASN.1 strings are represented internally within OpenSSL as an ASN1_STRING
  structure which contains a buffer holding the string data and a field holding
  the buffer length. This contrasts with normal C strings which are repesented 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 parsed using 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_STRING structure.

  However, it is possible for applications to directly construct valid ASN1_STRING
  structures which do not NUL terminate the byte array by directly setting the
  "data" and "length" fields in the ASN1_STRING array. This can also happen by
  using the ASN1_STRING_set0() function.

  Numerous OpenSSL functions that print ASN.1 data have been found to assume that
  the ASN1_STRING byte array will be NUL terminated, even though this is not
  guaranteed for strings that have been directly constructed. Where an application
  requests an ASN.1 structure to be printed, and where that ASN.1 structure
  contains ASN1_STRINGs that have been directly constructed by the application
  without NUL terminating the "data" field, then a read buffer overrun can occur.

  The same thing can also occur during name constraints processing of certificates
  (for example if a certificate has been directly constructed by the application
  instead of loading it via the OpenSSL parsing functions, and the certificate
  contains non NUL terminated ASN1_STRING structures). It can also occur in the
  X509_get1_email(), X509_REQ_get1_email() and X509_get1_ocsp() functions.

  If a malicious actor can cause an application to directly construct an
  ASN1_STRING and then process it through one of the affected OpenSSL functions
  then this issue could be hit. This might result in a crash (causing a Denial of
  Service attack). It could also result in the disclosure of private memory
  contents (such as private keys, or sensitive plaintext).
  (CVE-2021-3712)
  [Matt Caswell]

(jperkin)