Fixes the following security issues:
- CVE-2021-23841: Null pointer deref in X509_issuer_and_serial_hash()
The OpenSSL public API function X509_issuer_and_serial_hash() attempts to
create a unique hash value based on the issuer and serial number data
contained within an X509 certificate. However it fails to correctly
handle any errors that may occur while parsing the issuer field (which
might occur if the issuer field is maliciously constructed). This may
subsequently result in a NULL pointer deref and a crash leading to a
potential denial of service attack.
The function X509_issuer_and_serial_hash() is never directly called by
OpenSSL itself so applications are only vulnerable if they use this
function directly and they use it on certificates that may have been
obtained from untrusted sources.
- CVE-2021-23839: Incorrect SSLv2 rollback protection
OpenSSL 1.0.2 supports SSLv2. If a client attempts to negotiate SSLv2
with a server that is configured to support both SSLv2 and more recent SSL
and TLS versions then a check is made for a version rollback attack when
unpadding an RSA signature. Clients that support SSL or TLS versions
greater than SSLv2 are supposed to use a special form of padding. A
server that supports greater than SSLv2 is supposed to reject connection
attempts from a client where this special form of padding is present,
because this indicates that a version rollback has occurred (i.e. both
client and server support greater than SSLv2, and yet this is the version
that is being requested).
The implementation of this padding check inverted the logic so that the
connection attempt is accepted if the padding is present, and rejected if
it is absent. This means that such as server will accept a connection if
a version rollback attack has occurred. Further the server will
erroneously reject a connection if a normal SSLv2 connection attempt is
made.
OpenSSL 1.1.1 does not have SSLv2 support and therefore is not vulnerable
to this issue. The underlying error is in the implementation of the
RSA_padding_check_SSLv23() function. This also affects the
RSA_SSLV23_PADDING padding mode used by various other functions. Although
1.1.1 does not support SSLv2 the RSA_padding_check_SSLv23() function still
exists, as does the RSA_SSLV23_PADDING padding mode. Applications that
directly call that function or use that padding mode will encounter this
issue. However since there is no support for the SSLv2 protocol in 1.1.1
this is considered a bug and not a security issue in that version.
- CVE-2021-23840: Integer overflow in CipherUpdate
Calls to EVP_CipherUpdate, EVP_EncryptUpdate and EVP_DecryptUpdate may
overflow the output length argument in some cases where the input length
is close to the maximum permissable length for an integer on the platform.
In such cases the return value from the function call will be 1
(indicating success), but the output length value will be negative. This
could cause applications to behave incorrectly or crash.
For more details, see the advisory:
https://www.openssl.org/news/secadv/20210216.txt
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
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