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libsysdecode: PROT_MAX() decoding bug
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Authored by sigsys_gmail.com on Nov 22 2020, 8:07 AM.

Details

Summary

Small bug with with the regular protection bits not being decoded when there's a PROT_MAX.

Test Plan

Doesn't seem like anything uses explicit PROT_MAX()s in base. So here's a sample program to truss.

#include <stddef.h>
#include <sys/mman.h>
#include <sys/param.h>

int main() {
	int prots[] = { PROT_NONE, PROT_READ, PROT_WRITE, PROT_EXEC, PROT_READ|PROT_WRITE, PROT_READ|PROT_WRITE|PROT_EXEC };
	for (size_t i = 0; i < nitems(prots); i++)
		for (size_t j = 0; j < nitems(prots); j++)
			mmap(NULL, PAGE_SIZE, prots[i] | PROT_MAX(prots[j]), MAP_ANON, -1, 0);
	return (0);
}

Diff Detail

Repository
rS FreeBSD src repository - subversion
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.