On 11/24/2017 09:35 AM, Florian Weimer wrote:

On 11/24/2017 12:29 AM, Dave Hansen wrote:

quoted

Although weird, the thought here was that pkey_mprotect() callers are
new and should know about the interactions with PROT_EXEC.  They can
also*get*  PROT_EXEC semantics if they want.

The only wart here is if you do:

	mprotect(..., PROT_EXEC); // key 10 is now the PROT_EXEC key

I thought the PROT_EXEC key is always 1?

Seems it assigns the first non-allocated one. Can even fail if there's
none left, and then there's no PROT_EXEC read protection. In practice I
expect PROT_EXEC mapping to be created by ELF loader (?) before the
program can even call pkey_alloc() itself, so it would be 1.