252629 2021-01-13 03:15:08 +0000 Need infrastructure to set ELF feature note flags via elfctl 2025-03-02 11:55:15 +0000 1 1 1 Unclassified Ports & Packages Ports Framework Latest Any Any In Progress https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=239873 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=259968 --- Affects Only Me --- 252689 271838 273036 283836 239873 1 emaste portmgr dch dewayne kevans lwhsu manu ports-bugs oldest_to_newest 1141378 0 emaste 2021-01-13 03:15:08 +0000 [PR for issue tracking; I would like to discuss the desired approach before starting implementation] We have elfctl(1) which can set ELF feature flags, to indicate that a binary is incompatible with certain vulnerability mitigations. The current list of flags is: % elfctl -l Known features are: aslr Disable ASLR protmax Disable implicit PROT_MAX stackgap Disable stack gap wxneeded Requires W+X mappings I would like to have some canonical way to set these flags in ports, but I am not sure what the right interface is. It could be done in an ad-hoc manner in individual post-install targets, but I believe we'll want common infrastructure as different sets of flags will be available on different releases. Within an individual port we may have sets of files with different flags to be set. 1141381 1 emaste 2021-01-13 03:33:15 +0000 Although maybe we can allow elfctl to silently ignore unknown flags and use the same invocation across all releases - see https://reviews.freebsd.org/D28130. 1141383 2 emaste 2021-01-13 03:34:08 +0000 My world was out of date, currently known flags are: Known features are: aslr Disable ASLR protmax Disable implicit PROT_MAX stackgap Disable stack gap wxneeded Requires W+X mappings la48 amd64: Limit user VA to 48bit aslrstkgap Disable ASLR stack gap 1141386 3 commit-hook 2021-01-13 05:12:37 +0000 A commit in branch main references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=f6d95a01103a49a94c876d5a51bb4be25c06d964 commit f6d95a01103a49a94c876d5a51bb4be25c06d964 Author: Ed Maste <emaste@FreeBSD.org> AuthorDate: 2021-01-13 03:24:52 +0000 Commit: Ed Maste <emaste@FreeBSD.org> CommitDate: 2021-01-13 05:10:13 +0000 elftcl: add -i flag to ignore unknown flags This may allow an identical elfctl invocation to be used on multiple FreeBSD versions, with features not implemented on older releases being silently ignored. PR: 252629 (related) Reviewed by: kib MFC after: 1 week Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D28130 usr.bin/elfctl/elfctl.1 | 6 +++++- usr.bin/elfctl/elfctl.c | 13 ++++++++++--- 2 files changed, 15 insertions(+), 4 deletions(-) 1141405 4 manu 2021-01-13 08:54:36 +0000 Adding support in pkg(8) might be the way. Then adding some keyworks support in the plist like @elfctl aslr /path/to/bin @elfctl wxneeded /path/to/other/bin 1141406 5 manu 2021-01-13 08:59:53 +0000 While here, I think that it's a bit strange to do elfctl +aslr /path/to/bin to disable it 1141407 6 manu 2021-01-13 09:05:10 +0000 After looking at elfctl it seems that if we can set multiple features at a time we cannot do something like elfctl -e +aslr,-wxneeded /path/to/bin I think that would be good to have. For the keywords something like : @elfctl set <featurelist> /path/to/bin @elfctl clear <featurelist> /path/to/bin Would be nicer to what I've said earlier. 1141408 7 manu 2021-01-13 09:14:13 +0000 So what's needed is : - in pkg(8) add a lua callable function pkg.elfctl that takes a list of features and a path - In the portstree add a Keywords/elfctl.ucl that calls this lua function - Then in the plist of the ports just @elfctl <featurelist> /path/to/bin I would prefer if the featurelist is more intuitive that what's in elfctl "aslr" would enable it while "noaslr" would disable it etc ... 1141410 8 bapt 2021-01-13 09:17:35 +0000 I agree with manu this is the simplest way and the cleanest way 1141458 9 emaste 2021-01-13 15:25:19 +0000 (In reply to Emmanuel Vadot from comment #6) > elfctl -e +aslr,-wxneeded /path/to/bin For tagging at build time I expect we'd use = and just set the bits we want. In general I think there would not be a need to turn off bits in ports builds. 1141522 10 dewayne 2021-01-13 21:52:24 +0000 (In reply to Emmanuel Vadot from comment #7) Please bear in mind that lua may not be functional in some environments. In src.conf, I have WITHOUT_LOADER_LUA=YES which I suspect is the cause of pkg being unable to process lua scripts (on FreeBSD12.2 r368820M). Is lua a prerequisite for pkg use on FreeBSD? 1141523 11 kevans 2021-01-13 21:53:56 +0000 (In reply to dewayne from comment #10) pkg has its own lua, this knob is irrelevant. 1142401 12 commit-hook 2021-01-19 02:50:30 +0000 A commit in branch stable/12 references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=369a4023e671c35390574d42b1b409b55946faf8 commit 369a4023e671c35390574d42b1b409b55946faf8 Author: Ed Maste <emaste@FreeBSD.org> AuthorDate: 2021-01-13 03:24:52 +0000 Commit: Ed Maste <emaste@FreeBSD.org> CommitDate: 2021-01-19 02:49:55 +0000 elftcl: add -i flag to ignore unknown flags This may allow an identical elfctl invocation to be used on multiple FreeBSD versions, with features not implemented on older releases being silently ignored. PR: 252629 (related) Reviewed by: kib Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D28130 (cherry picked from commit f6d95a01103a49a94c876d5a51bb4be25c06d964) usr.bin/elfctl/elfctl.1 | 6 +++++- usr.bin/elfctl/elfctl.c | 13 ++++++++++--- 2 files changed, 15 insertions(+), 4 deletions(-) 1143020 13 emaste 2021-01-22 17:31:19 +0000 Another proposed change to allow flags to be set by value: https://reviews.freebsd.org/D28284 then we could do e.g. NT_FREEBSD_FCTL_ASLR_DISABLE=0x1 NT_FREEBSD_FCTL_PROTMAX_DISABLE=0x2 NT_FREEBSD_FCTL_STKGAP_DISABLE=0x4 elfctl -e =${NT_FREEBSD_FCTL_ASLR_DISABLE},${NT_FREEBSD_FCTL_STKGAP_DISABLE} /path/to/file 1143030 14 commit-hook 2021-01-22 19:41:32 +0000 A commit in branch main references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=86f33b5fcf6087bf4439881011b920ff99e6e300 commit 86f33b5fcf6087bf4439881011b920ff99e6e300 Author: Ed Maste <emaste@FreeBSD.org> AuthorDate: 2021-01-22 17:22:35 +0000 Commit: Ed Maste <emaste@FreeBSD.org> CommitDate: 2021-01-22 19:38:52 +0000 elfctl: allow features to be specified by value This will allow elfctl on older releases to set bits that are not yet known there, so that the binary will have the correct settings applied if run on a later FreeBSD version. PR: 252629 (related) Suggested by: kib Reviewed by: gbe (manpage, earlier), kib MFC after: 3 days Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D28284 usr.bin/elfctl/elfctl.1 | 15 +++++++++++++-- usr.bin/elfctl/elfctl.c | 25 ++++++++++++++++++++++--- 2 files changed, 35 insertions(+), 5 deletions(-) 1143632 15 commit-hook 2021-01-26 14:47:54 +0000 A commit in branch stable/12 references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=d7e23b5cdd8465bd50f88b1e38cb695a361a26f5 commit d7e23b5cdd8465bd50f88b1e38cb695a361a26f5 Author: Ed Maste <emaste@FreeBSD.org> AuthorDate: 2021-01-22 17:22:35 +0000 Commit: Ed Maste <emaste@FreeBSD.org> CommitDate: 2021-01-26 14:46:00 +0000 elfctl: allow features to be specified by value This will allow elfctl on older releases to set bits that are not yet known there, so that the binary will have the correct settings applied if run on a later FreeBSD version. PR: 252629 (related) Suggested by: kib Reviewed by: gbe (manpage, earlier), kib Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D28284 (cherry picked from commit 86f33b5fcf6087bf4439881011b920ff99e6e300) elfctl: fix typo from last-minute refactoring Reported by: jkim (cherry picked from commit f302fd1aa6730facd53a3f761e0a57302731b03e) elfctl: Fix type errors. Target value for val has uint32_t type, not uint, adjust used constant. Change val type to unsigned so that left and right sides of comparision operator do not expose different signed types of same range [*]. Switch to unsigned long long and strtoll(3) so that 0x80000000 is accepted by conversion function [**]. Reported by: kargl [*] Noted by: emaste [**] Reviewed by: emaste Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D28301 (cherry picked from commit 9940ac808de7b7d4ed0408c3e739f667dca06d3b) usr.bin/elfctl/elfctl.1 | 15 +++++++++++++-- usr.bin/elfctl/elfctl.c | 26 +++++++++++++++++++++++--- 2 files changed, 36 insertions(+), 5 deletions(-) 1143738 16 commit-hook 2021-01-27 00:26:40 +0000 A commit in branch stable/13 references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=f2b5999b2166579a2ebd4b5e117a17574f18d50f commit f2b5999b2166579a2ebd4b5e117a17574f18d50f Author: Ed Maste <emaste@FreeBSD.org> AuthorDate: 2021-01-22 17:22:35 +0000 Commit: Ed Maste <emaste@FreeBSD.org> CommitDate: 2021-01-26 14:44:12 +0000 elfctl: allow features to be specified by value This will allow elfctl on older releases to set bits that are not yet known there, so that the binary will have the correct settings applied if run on a later FreeBSD version. PR: 252629 (related) Suggested by: kib Reviewed by: gbe (manpage, earlier), kib Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D28284 (cherry picked from commit 86f33b5fcf6087bf4439881011b920ff99e6e300) elfctl: fix typo from last-minute refactoring Reported by: jkim (cherry picked from commit f302fd1aa6730facd53a3f761e0a57302731b03e) elfctl: Fix type errors. Target value for val has uint32_t type, not uint, adjust used constant. Change val type to unsigned so that left and right sides of comparision operator do not expose different signed types of same range [*]. Switch to unsigned long long and strtoll(3) so that 0x80000000 is accepted by conversion function [**]. Reported by: kargl [*] Noted by: emaste [**] Reviewed by: emaste Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D28301 (cherry picked from commit 9940ac808de7b7d4ed0408c3e739f667dca06d3b) usr.bin/elfctl/elfctl.1 | 15 +++++++++++++-- usr.bin/elfctl/elfctl.c | 26 +++++++++++++++++++++++--- 2 files changed, 36 insertions(+), 5 deletions(-) 1352698 17 linimon 2025-03-02 11:55:15 +0000 ^Triage: is there anything else that needs to be done to close this PR?