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rtld: When relocating, map without PROT_EXEC
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Authored by emaste on Jan 4 2021, 5:44 PM.

Details

Summary

This makes text segment relocation work under W^X.


I have encountered this when loading lucet-compiled shared objects with W^X (D24933).

Diff Detail

Repository
R10 FreeBSD src repository
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Automatic diff as part of commit; lint not applicable.
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Event Timeline

libexec/rtld-elf/rtld.c
2985–2986

maybe clearer if we incorporate the PROT_WRITE part from above?

something like

prot = convert_prot(ph->p_flags);
if (before)
        prot = prot & ~PROT_EXEC | PROT_WRITE;
libexec/rtld-elf/rtld.c
2985–2986

There is no much reason to use convert_prot() in'before' case at all, then. Only PF_R survives. It can be

prot = before ? (PROT_READ | PROT_WRITE) : convert_prot(ph->p_flags);
emaste updated this revision to Diff 81672.
emaste edited reviewers, added: greg_unrelenting.technology; removed: emaste.

Update per kib's suggestion

This revision is now accepted and ready to land.Jan 5 2021, 3:04 PM
This revision was automatically updated to reflect the committed changes.