ASN1_primitive_new takes an ASN1_ITEM * param |it|. There are a couple
of conditional code paths that check whether |it| is NULL or not - but
later |it| is deref'd unconditionally. If |it| was ever really NULL then
this would seg fault. In practice ASN1_primitive_new is marked as an
internal function in the public header file. The only places it is ever
used internally always pass a non NULL parameter for |it|. Therefore, change
the code to sanity check that |it| is not NULL, and remove the conditional
checking.
(Imported from upstream's 9e488fd6ab2c295941e91a47ab7bcd346b7540c7)
Change-Id: Icbb13cd00d0ec5529871b678b0bcc465956a7572
Reviewed-on: https://boringssl-review.googlesource.com/4006
Reviewed-by: Adam Langley <agl@google.com>