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arm, arm64, i386: tweak hard-coded load addresses for PIE binaries
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Authored by kib on Oct 22 2022, 11:02 AM.
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Details

Summary
They are used when ASLR is not applied.
The need for adjusting is due to rtld direct exec mode puts ld-elf.so.1
at the PIE load address, and this address must not conflict with the
default linker' load address for non-PIE binaries.  Otherwise rtld in
direct mode cannot activate image.  Example of implicit failure is ldd(1)
refusing to run.

Reported by:    kp
i386: move hard-coded load address for PIE below default linker base

both for i386 native and compat32 amd64.  We know the ld-elf.so.1 size
in advance, it fits there.  Trying to push it up after the end of a
binary cannot work reliably and eventually fail for large binaries.

Diff Detail

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rG FreeBSD src repository
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kib requested review of this revision.Oct 22 2022, 11:02 AM
kib added a reviewer: andrew.

What of the i386 failure example that https://lists.freebsd.org/archives/dev-commits-src-main/2022-October/010362.html reports:

[ -z "ldd " ] || [ -z "`ldd  install/q2map.i386 2>&1 1>/dev/null | tee /dev/stderr`" ] || { rm -f install/q2map.i386; exit 1; }
ld-elf.so.1: install/q2map.i386: mmap of entire address space failed: Cannot allocate memory
install/q2map.i386: exit status 1
gmake[1]: *** [Makefile:461: install/q2map.i386] Error 1
gmake[1]: *** Waiting for unfinished jobs....
[ -z "ldd " ] || [ -z "`ldd  install/qdata3.i386 2>&1 1>/dev/null | tee /dev/stderr`" ] || { rm -f install/qdata3.i386; exit 1; }
ld-elf.so.1: install/qdata3.i386: mmap of entire address space failed: Cannot allocate memory
install/qdata3.i386: exit status 1

as shown in the build server log: http://beefy17.nyi.freebsd.org/data/main-i386-default/pce69f38a72dd_s9c95013905/logs/netradiant-20150621_4.log ?

Does 32-bit powerpc ldd on powerpc64 variants that support 32-bit powerpc code have the issue for chroot/jail use of 32-bit worlds as well? (I no longer have access to powerpc/power family members and so can not test.)

This patch also allows our builds to complete.

kib edited the summary of this revision. (Show Details)

Handle i386

kib retitled this revision from arm, arm64: tweak hard-coded load addresses for PIE binaries to arm, arm64, i386: tweak hard-coded load addresses for PIE binaries.Oct 22 2022, 8:28 PM