Bug 2208504

Summary:	redhat-rpm-config: hardening does not enable PIC mode for assembler files
Product:	Red Hat Enterprise Linux 9	Reporter:	Tomas Hoger <thoger>
Component:	redhat-rpm-config	Assignee:	Florian Weimer <fweimer>
Status:	CLOSED MIGRATED	QA Contact:	swm-qe
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	9.2	CC:	ajax, carl, codonell, extras-qa, fberat, ffesti, fweimer, igor.raits, j, maxwell, mhroncok, ngompa13, nickc, pmatilai, sipoyare, thoger, torsava, vdronov
Target Milestone:	rc	Keywords:	Bugfix, MigratedToJIRA, Patch, Triaged
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:	2167430	Environment:
Last Closed:	2023-09-21 17:12:30 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2167430
Bug Blocks:

Description Tomas Hoger 2023-05-19 09:49:47 UTC

+++ This bug was initially created as a clone of Bug #2167430 +++

Hi. It looks like Fedora/RH build systems hardening (/usr/lib/rpm/redhat/redhat-hardened-cc1) does
not enable PIC mode for assembler files. This is so for both Koji and Brew builders. Some research
and some conclusions follow.

A test C or Assembly code containing some check if it is build in PIC mode or not can be just like:

#if defined(__PIC__)
#warning defined __PIC__
#else
#warning no __PIC__
#endif

This works both for C and assembly code when a PIC build is requested in a usual way with "-fPIE":

$ gcc -fPIE picpie.c
picpie.c:8:2: warning: #warning defined __PIC__ [-Wcpp]

$ gcc -fPIE picpie.S
picpie.S:8:2: warning: #warning defined __PIC__ [-Wcpp]
 
Brew/Koji build system forces PIC in an indirect way using GCC specs:

gcc -DHAVE_CONFIG_H -I.     -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches
-pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong
-specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m32 -march=i686 -mtune=generic -msse2 -mfpmath=sse
-mstackrealign -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection
-c -o rdrand_asm.o rdrand_asm.S

It turns out that this indirect way of forcing PIC works fine with C code but does not work with Asm.
I've tried to adjust redhat-hardened-cc1 specs to work for assembly sources also, but to no success:

$ gcc -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 picpie.c
picpie.c:8:2: warning: #warning defined __PIC__ [-Wcpp]

$ gcc -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 picpie.S
picpie.S:10:2: warning: #warning no __PIC__ [-Wcpp]

This means a PIC-aware assembly code is not built as PIC in our build systems Brew and Koji.

See https://kojihub.stream.rdu2.redhat.com/kojifiles/work/tasks/796/1840796/build.log as an example:
(task: https://kojihub.stream.rdu2.redhat.com/koji/taskinfo?taskID=1840796)

gcc      -I/usr/include/libxml2    -pthread -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m32 -march=i686 -mtune=generic -msse2 -mfpmath=sse -mstackrealign -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -pthread -Wl,-z,relro -Wl,--as-needed  -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -o rngd rngd-rngd.o rngd-rngd_entsource.o rngd-rngd_linux.o rngd-util.o rngd-ossl_helpers.o rngd-rngd_nistbeacon.o rngd-rngd_rdrand.o rdrand_asm.o  rngd-rngd_jitter.o  rngd-rngd_qrypt.o   librngd.a -ljitterentropy     -ljansson  -lcurl  -lxml2  -lssl -lcrypto  -lcap    -ljitterentropy 
make[2]: Leaving directory '/builddir/build/BUILD/rng-tools-6.15'
/usr/bin/ld: rdrand_asm.o: warning: relocation in read-only section `.text'
/usr/bin/ld: warning: creating DT_TEXTREL in a PIE

The result here is 'rngd' executable which is supposed to be PIE is not exactly PIE, rpminspect reports:

elf: BAD: Security: /usr/sbin/rngd in rng-tools has TEXTREL relocations on i686
Suggested remedy: Ensure all object files are compiled with -fPIC

This looks like some security issue to me, though in quite a corner case - PIC-aware assembly code.
I believe it would be great if /usr/lib/rpm/redhat/redhat-hardened-cc1 is adjusted so assmbly code sees __PIC__ and __PIE__ set
the same way it is done for C code.

Comment 1 RHEL Program Management 2023-09-21 16:28:09 UTC

Issue migration from Bugzilla to Jira is in process at this time. This will be the last message in Jira copied from the Bugzilla bug.

Comment 2 RHEL Program Management 2023-09-21 17:12:30 UTC

This BZ has been automatically migrated to the issues.redhat.com Red Hat Issue Tracker. All future work related to this report will be managed there.

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