Rusty Russell <ru...@rustcorp.com.au> wrote: > Meh, I really wanted to separate the module signature locating (my > problem) from the decoding and checking (your problem).
You could split mod_verify_sig() at the: /* For the moment, only support RSA and X.509 identifiers */ comment. At that point we have verified the size fields of the module_signature struct and we have determined mod, modlen and sig. Assuming a detached signature is going to look the same as an attached signature, just without the magic number[1], then you can duplicate the first part of mod_verify_sig() with the size checks. [1] The signature may need to be kept small to make sure it will fit within an xattr, just in case the host fs has limits. > If we're going to require such a header, we can simplify further (untested!). Do we want to require that a detached signature be exactly the same as an appended signature, structure, magic string and all? I'm also slightly against copying the magic string to the stack if we can avoid it as the compiler can't recover the space before calling mod_verify_sig(). Besides, there's no particular need to copy the magic string. > BTW, I'm not convinced your use of bitfields here is portable; it may be > portable enough for Linux though. I consulted a gcc engineer and he suggested that it's arch dependent, so I should probably use u8. Since the enums are basically int-sized types, the compiler might reorder them depending on endianness and might insert a byte of padding. It's just that I prefer the enums for documentary sake. David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/