[Bug 2054343] Re: CVE-2023-4039: ARM64 GCC

Thu Oct 10 21:16:35 UTC 2024

Patches for gcc-9:

	$ git config --add remote.origin.fetch '+refs/vendors/ARM/heads/CVE-2023-4039/gcc-9:refs/remotes/origin/ARM_CVE-2023-4039_gcc-9'
	$ git fetch

	$ git log --oneline origin/ARM_CVE-2023-4039_gcc-9 | head -n11
	bf3eeaa0182a aarch64: Make stack smash canary protect saved registers
	f2684e63652b aarch64: Simplify probe of final frame allocation
	12517baf6c88 aarch64: Put LR save probe in first 16 bytes
	4dd8925d95d3 aarch64: Tweak stack clash boundary condition
	cfed3b87e935 Backport check-function-bodies support
	eb2271eb6bb6 aarch64: Tweak frame_size comment
	16016465ff28 aarch64: Rename hard_fp_offset to bytes_above_hard_fp
	4604c4cd0a6c aarch64: Rename locals_offset to bytes_above_locals
	347487fffa02 aarch64: Add bytes_below_hard_fp to frame info
	78ebdb7b12d5 aarch64: Explicitly handle frames with no saved registers
	7a15b5060a83 Update ChangeLog and version files for release

Gitweb:
	https://gcc.gnu.org/git/?p=gcc.git;a=shortlog;h=bf3eeaa0182a92987570d9c787bd45079eebf528&hp=7a15b5060a83ea8282323d92043c6152e6a3e22d

Generated a single .patch file just like src:gcc-9's d/p/git-
updates.diff

	LANG=C git diff --no-renames --src-prefix=a/src/ --dst-prefix=b/src/ \
		78ebdb7b12d5e258b9811bab715734454268fd0c^ bf3eeaa0182a92987570d9c787bd45079eebf528 \
		| awk '/^diff .*\.texi/ {skip=1; next} /^diff / { skip=0 } skip==0' \
		| grep -v -E '^(diff|index)' \
		> cve-2023-4039.diff

For verification purposes, this patch can be cleanly reverted
from the gcc-9 package that introduced its changes in Noble:

        gcc-9 (9.5.0-6) unstable; urgency=medium

	  * Address stack protector and stack clash protection weaknesses
	    on AArch64. CVE-2023-4039.

	$ pull-lp-source gcc-9 noble 9.5.0-6ubuntu1
	$ cd gcc-9-9.5.0/
	$ debian/rules patch
	$ patch -R -p1 -F0 --dry-run < /tmp/gcc-9/cve-2023-4039.diff
	checking file src/gcc/config/aarch64/aarch64.c
	checking file src/gcc/config/aarch64/aarch64.h
	checking file src/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-17.c
	checking file src/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-18.c
	checking file src/gcc/testsuite/gcc.target/aarch64/stack-protector-8.c
	checking file src/gcc/testsuite/gcc.target/aarch64/stack-protector-9.c
	checking file src/gcc/testsuite/lib/scanasm.exp
	$ echo $?
	0

Changelog entry:

        'd/p/cve-2023-4039.diff: Address stack protector and stack clash
protection weaknesses on AArch64. CVE-2023-4039. (LP: #2054343) Taken
from the vendors/ARM/heads/CVE-2023-4039/gcc-9 branch.'

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https://bugs.launchpad.net/bugs/2054343

Title:
  CVE-2023-4039: ARM64 GCC

Status in gcc-10 package in Ubuntu:
  Fix Released
Status in gcc-11 package in Ubuntu:
  Fix Released
Status in gcc-12 package in Ubuntu:
  Fix Released
Status in gcc-13 package in Ubuntu:
  Fix Released
Status in gcc-9 package in Ubuntu:
  Fix Released
Status in gcc-10 source package in Focal:
  Triaged
Status in gcc-9 source package in Focal:
  Won't Fix
Status in gcc-10 source package in Jammy:
  Triaged
Status in gcc-11 source package in Jammy:
  Triaged
Status in gcc-12 source package in Jammy:
  Triaged
Status in gcc-9 source package in Jammy:
  Triaged
Status in gcc-10 source package in Noble:
  Fix Released
Status in gcc-11 source package in Noble:
  Fix Released
Status in gcc-12 source package in Noble:
  Fix Released
Status in gcc-13 source package in Noble:
  Fix Released

Bug description:
  [Impact]

  Some gcc versions in Jammy and Focal are still
  vulnerable to the arm64-specific CVE-2023-4039
  (-fstack-protector guard failures with dynamic
  stack allocations).

  This impacts detecting, e.g., buffer overflows,
  resulting in less secure Ubuntu arm64 packages
  and user-built binaries.

  [Test Plan]

  Use the test-case in the vulnerability post [1],
  as in comments #20 and #21.

  Without patches, the test fails with Bus Error
  and a register value modified by the program.

  With the patches, the test fails with Aborted
  (buffer overflow detected) and register value
  unmodified.

  [1] https://rtx.meta.security/mitigation/2023/09/12/CVE-2023-4039.html

  [Regression Potential]

  The patchset modifies arm64-specific code gen,
  therefore any arm64 program might be affected,
  while other architectures should not.

  That is, signs of regressions from this would
  manifest as errors seen only in arm64 programs
  but not in other architectures.

  Potential fallout is expected to occur early
  and/or with dynamic allocations in the stack,
  and could manifest in different, subtle ways.

  That is concerning, however, fortunately this
  patchset has been introduced for a while now
  in the _same gcc versions_ in _newer_ series.

  That gives confidence to SRU the _same_ change
  to the _same_ gcc versions (to _older_ series).

  [Other Info]

  - gcc-14: fixed in Noble/Oracular (comment #22)
  - gcc-13: fixed in Noble/Oracular (comment #23)
  - gcc-12: fixed in Noble/Oracular, NOT in Jammy (comment #13)
  - gcc-11: fixed in Noble/Oracular, NOT in Jammy (comment #14)
  - gcc-10: fixed in Noble/Oracular, NOT in Jammy/Focal (comment #15)
  - gcc-9: fixed in Noble/Oracular, NOT in Jammy/Focal (comment #16)

  The fix for gcc-9/Focal FTBFS due to an Ada-related check.
  For the moment, it's not going to be pursued/analyzed more
  as agreed with the original reporter (sufficient for them).
  If others need it, please reopen and analyze/fix the error.

  For more information about the issue and patches: [2]
  [2] https://developer.arm.com/Arm%20Security%20Center/GCC%20Stack%20Protector%20Vulnerability%20AArch64#Technical-Specifications

  [Original Bug Description]
  See https://launchpad.net/ubuntu/+source/gcc-10/10.5.0-3ubuntu1/+build/27746786/+files/buildlog_ubuntu-noble-arm64.gcc-10_10.5.0-3ubuntu1_BUILDING.txt.gz

  The above build is supposed to address
  https://nvd.nist.gov/vuln/detail/CVE-2023-4039

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