Possible denial of service in X.509 name checks

Issue summary: Applications performing certificate name checks (e.g., TLS

clients checking server certificates) may attempt to read an invalid memory

address resulting in abnormal termination of the application process.

Impact summary: Abnormal termination of an application can a cause a denial of

service.

Applications performing certificate name checks (e.g., TLS clients checking

server certificates) may attempt to read an invalid memory address when

comparing the expected name with an `otherName` subject alternative name of an

X.509 certificate. This may result in an exception that terminates the

application program.

Note that basic certificate chain validation (signatures, dates, ...) is not

affected, the denial of service can occur only when the application also

specifies an expected DNS name, Email address or IP address.

TLS servers rarely solicit client certificates, and even when they do, they

generally don't perform a name check against a reference identifier (expected

identity), but rather extract the presented identity after checking the

certificate chain. So TLS servers are generally not affected and the severity

of the issue is Moderate.

The FIPS modules in 3.3, 3.2, 3.1 and 3.0 are not affected by this issue.