Differential D25966

Preserve ASLR vm_map flags across fork.
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Authored by brooks on Aug 5 2020, 7:50 PM.

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Reviewers

markj
kib

Commits

rS364087: MFC r363966:
rS363966: Preserve ASLR vm_map flags across fork

Summary

In the most common case (fork+execve) this doesn't matter, but further
attempts to apply entropy would fail in (e.g.) a pre-fork server.

Reported by: Alfredo Mazzinghi

Test Plan

A variant of this patch preserving an additional local flag
works in CheriBSD.

Diff Detail

Repository

rS FreeBSD src repository - subversion

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Lint Not Applicable

Unit

Tests Not Applicable

Event Timeline

brooks requested review of this revision.Aug 5 2020, 7:50 PM

brooks created this revision.

Harbormaster completed remote builds in B32782: Diff 75448.Aug 5 2020, 7:50 PM

kib added inline comments.Aug 5 2020, 8:25 PM

sys/vm/vm_map.c
4102 ↗	(On Diff #75448)	() are excessive. Also I suggest to move the line right after new_map assignment (line 4098), no need for blank lines around.
sys/vm/vm_map.h
226 ↗	(On Diff #75448)	It is single-use symbol, it is easier to read code when flags are listed explicitly in vmspace_fork().

Relocate flags assignment and don't use a variable.

Harbormaster completed remote builds in B32783: Diff 75449.Aug 5 2020, 8:52 PM

brooks marked an inline comment as done.Aug 5 2020, 8:52 PM

kib accepted this revision.Aug 5 2020, 9:11 PM

This revision is now accepted and ready to land.Aug 5 2020, 9:11 PM

markj accepted this revision.Aug 6 2020, 3:48 PM

Closed by commit rS363966: Preserve ASLR vm_map flags across fork (authored by brooks). · Explain WhyAug 6 2020, 4:20 PM

This revision was automatically updated to reflect the committed changes.

brooks added a commit: rS363966: Preserve ASLR vm_map flags across fork.

Herald added a subscriber: imp. · View Herald TranscriptAug 6 2020, 4:20 PM

brooks added a commit: rS364087: MFC r363966:.Aug 10 2020, 6:26 PM

Revision Contents
Changeset List

Path

Size

head/

sys/

vm/

1 line

Diff 75509

head/sys/vm/vm_map.c

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