libsepol/cil: Check if identifier is NULL when verifying name

Nicolas Iooss found while fuzzing secilc with AFL that the statement
"(class C (()))" will cause a segfault.

When CIL checks the syntax of the class statement it sees "(())" as a
valid permission list, but since "()" is not an identifier a NULL is
passed as the string for name verification. A segfault occurs because
name verification assumes that the string being checked is non-NULL.

Check if identifier is NULL when verifying name.

Signed-off-by: James Carter <jwcart2@tycho.nsa.gov>
1 file changed