Add missing module flags for `-Zfunction-return=thunk-extern` by Darksonn · Pull Request #130824 · rust-lang/rust (original) (raw)

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service andprivacy statement. We’ll occasionally send you account related emails.

Already on GitHub?Sign in to your account

Conversation7 Commits1 Checks6 Files changed

Conversation

This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.Learn more about bidirectional Unicode characters

[ Show hidden characters]({{ revealButtonHref }})

This fixes a bug in the -Zfunction-return=thunk-extern flag. The flag needs to be passed onto LLVM to ensure that functions such as asan.module_ctor and asan.module_dtor that are created internally in LLVM have the mitigation applied to them.

This was originally discovered in the Linux kernel.

Original flag PR: #116892
PR for similar issue: #129373
Tracking issue: #116853

cc @ojeda
r? @wesleywiser

Click to see output with and without PR

Without this PR:

aliceryhl@aliceryhl-l:~/rust-for-linux$ rustc --version --verbose
rustc 1.81.0 (eeb90cda1 2024-09-04)
binary: rustc
commit-hash: eeb90cda1969383f56a2637cbd3037bdf598841c
commit-date: 2024-09-04
host: x86_64-unknown-linux-gnu
release: 1.81.0
LLVM version: 18.1.7

aliceryhl@aliceryhl-l:~/rust-for-linux$ make LLVM=1 O=~/lout 
make[1]: Entering directory '/home/aliceryhl/lout'
  SYNC    include/config/auto.conf.cmd
  GEN     Makefile
  GEN     Makefile
  CALL    /home/aliceryhl/rust-for-linux/scripts/checksyscalls.sh
  DESCEND objtool
  INSTALL libsubcmd_headers
  RUSTC L rust/core.o
rust/core.o: warning: objtool: asan.module_ctor+0x13: 'naked' return found in MITIGATION_RETHUNK build
rust/core.o: warning: objtool: asan.module_dtor+0x13: 'naked' return found in MITIGATION_RETHUNK build
  EXPORTS rust/exports_core_generated.h
  RUSTC P rust/libmacros.so
  RUSTC L rust/compiler_builtins.o
rust/compiler_builtins.o: warning: objtool: asan.module_ctor+0x0: 'naked' return found in MITIGATION_RETHUNK build
  RUSTC L rust/alloc.o
rust/alloc.o: warning: objtool: asan.module_ctor+0x13: 'naked' return found in MITIGATION_RETHUNK build
rust/alloc.o: warning: objtool: asan.module_dtor+0x13: 'naked' return found in MITIGATION_RETHUNK build
  EXPORTS rust/exports_alloc_generated.h
  RUSTC L rust/bindings.o
rust/bindings.o: warning: objtool: asan.module_ctor+0x0: 'naked' return found in MITIGATION_RETHUNK build
  EXPORTS rust/exports_bindings_generated.h
  RUSTC L rust/build_error.o
  RUSTC L rust/uapi.o
rust/uapi.o: warning: objtool: asan.module_ctor+0x0: 'naked' return found in MITIGATION_RETHUNK build
  RUSTC L rust/kernel.o
rust/kernel.o: warning: objtool: asan.module_ctor+0x13: 'naked' return found in MITIGATION_RETHUNK build
rust/kernel.o: warning: objtool: asan.module_dtor+0x13: 'naked' return found in MITIGATION_RETHUNK build
  EXPORTS rust/exports_kernel_generated.h
  CC      rust/exports.o
  AR      rust/built-in.a
  RUSTC     samples/rust/rust_print.o
samples/rust/rust_print.o: warning: objtool: asan.module_ctor+0x13: 'naked' return found in MITIGATION_RETHUNK build
samples/rust/rust_print.o: warning: objtool: asan.module_dtor+0x13: 'naked' return found in MITIGATION_RETHUNK build
  AR      samples/rust/built-in.a
  AR      samples/built-in.a
  AR      built-in.a
  AR      vmlinux.a
  LD      vmlinux.o
  OBJCOPY modules.builtin.modinfo
  GEN     modules.builtin
  MODPOST vmlinux.symvers
  UPD     include/generated/utsversion.h
  CC      init/version-timestamp.o
  LD      vmlinux
  NM      System.map
  SORTTAB vmlinux
  VOFFSET arch/x86/boot/compressed/../voffset.h
  CC      arch/x86/boot/compressed/misc.o
  OBJCOPY arch/x86/boot/compressed/vmlinux.bin
  GZIP    arch/x86/boot/compressed/vmlinux.bin.gz
  MKPIGGY arch/x86/boot/compressed/piggy.S
  AS      arch/x86/boot/compressed/piggy.o
  LD      arch/x86/boot/compressed/vmlinux
  ZOFFSET arch/x86/boot/zoffset.h
  AS      arch/x86/boot/header.o
  CC      arch/x86/boot/version.o
  LD      arch/x86/boot/setup.elf
  OBJCOPY arch/x86/boot/setup.bin
  OBJCOPY arch/x86/boot/vmlinux.bin
  BUILD   arch/x86/boot/bzImage
Kernel: arch/x86/boot/bzImage is ready  (#5)
make[1]: Leaving directory '/home/aliceryhl/lout'

With this PR:

aliceryhl@aliceryhl-l:~/rust-for-linux$ rustc --version --verbose
rustc 1.83.0-dev
binary: rustc
commit-hash: unknown
commit-date: unknown
host: x86_64-unknown-linux-gnu
release: 1.83.0-dev
LLVM version: 19.1.0

aliceryhl@aliceryhl-l:~/rust-for-linux$ make LLVM=1 O=~/lout 
make[1]: Entering directory '/home/aliceryhl/lout'
  SYNC    include/config/auto.conf.cmd
  GEN     Makefile
  GEN     Makefile
  CALL    /home/aliceryhl/rust-for-linux/scripts/checksyscalls.sh
  DESCEND objtool
  INSTALL libsubcmd_headers
  RUSTC L rust/core.o
  EXPORTS rust/exports_core_generated.h
  RUSTC P rust/libmacros.so
  RUSTC L rust/compiler_builtins.o
  RUSTC L rust/alloc.o
  EXPORTS rust/exports_alloc_generated.h
  RUSTC L rust/bindings.o
  EXPORTS rust/exports_bindings_generated.h
  RUSTC L rust/build_error.o
  RUSTC L rust/uapi.o
  RUSTC L rust/kernel.o
  EXPORTS rust/exports_kernel_generated.h
  CC      rust/exports.o
  AR      rust/built-in.a
  RUSTC     samples/rust/rust_print.o
  AR      samples/rust/built-in.a
  AR      samples/built-in.a
  AR      built-in.a
  AR      vmlinux.a
  LD      vmlinux.o
  OBJCOPY modules.builtin.modinfo
  GEN     modules.builtin
  MODPOST vmlinux.symvers
  UPD     include/generated/utsversion.h
  CC      init/version-timestamp.o
  LD      vmlinux
  NM      System.map
  SORTTAB vmlinux
  VOFFSET arch/x86/boot/compressed/../voffset.h
  CC      arch/x86/boot/compressed/misc.o
  OBJCOPY arch/x86/boot/compressed/vmlinux.bin
  GZIP    arch/x86/boot/compressed/vmlinux.bin.gz
  MKPIGGY arch/x86/boot/compressed/piggy.S
  AS      arch/x86/boot/compressed/piggy.o
  LD      arch/x86/boot/compressed/vmlinux
  ZOFFSET arch/x86/boot/zoffset.h
  AS      arch/x86/boot/header.o
  CC      arch/x86/boot/version.o
  LD      arch/x86/boot/setup.elf
  OBJCOPY arch/x86/boot/setup.bin
  OBJCOPY arch/x86/boot/vmlinux.bin
  BUILD   arch/x86/boot/bzImage
Kernel: arch/x86/boot/bzImage is ready  (#6)
make[1]: Leaving directory '/home/aliceryhl/lout'

rustbot added S-waiting-on-review

Status: Awaiting review from the assignee but also interested parties.

T-compiler

Relevant to the compiler team, which will review and decide on the PR/issue.

labels

Sep 25, 2024

ojeda mentioned this pull request

Sep 25, 2024

95 tasks

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Looks good to me -- thanks for fixing this!

ojeda pushed a commit to ojeda/linux that referenced this pull request

Sep 26, 2024

When enabling both KASAN and RETHUNK, objtool emits the following warnings:

rust/core.o: warning: objtool: asan.module_ctor+0x13: 'naked' return found in MITIGATION_RETHUNK build
rust/core.o: warning: objtool: asan.module_dtor+0x13: 'naked' return found in MITIGATION_RETHUNK build

This is caused by the -Zfunction-return=thunk-extern flag in rustc not informing LLVM about the mitigation at the module level (it does so at the function level only currently, which covers most cases, but both are required), which means that the KASAN functions asan.module_ctor and asan.module_dtor are generated without the rethunk mitigation.

The other mitigations that we enabled for Rust (SLS, RETPOLINE) do not have the same bug, as they're being applied through the target-feature functionality instead.

This is being fixed for rustc 1.83.0, so update Kconfig to reject this configuration on older compilers.

Link: rust-lang/rust#130824 Fixes: d786855 ("x86/rust: support MITIGATION_RETHUNK") Reported-by: Miguel Ojeda ojeda@kernel.org Closes: https://lore.kernel.org/all/CANiq72myZL4_poCMuNFevtpYYc0V0embjSuKb7y=C+m3vVA_8g@mail.gmail.com/ Signed-off-by: Alice Ryhl aliceryhl@google.com Link: https://lore.kernel.org/r/20240926093849.1192264-1-aliceryhl@google.com [ Reworded to add the details mentioned in the list. - Miguel ] Signed-off-by: Miguel Ojeda ojeda@kernel.org

📌 Commit 540e41f has been approved by wesleywiser

It is now in the queue for this repository.

bors added S-waiting-on-bors

Status: Waiting on bors to run and complete tests. Bors will change the label on completion.

and removed S-waiting-on-review

Status: Awaiting review from the assignee but also interested parties.

labels

Oct 7, 2024

GuillaumeGomez added a commit to GuillaumeGomez/rust that referenced this pull request

Oct 7, 2024

bors added a commit to rust-lang-ci/rust that referenced this pull request

Oct 7, 2024

…llaumeGomez

Rollup of 4 pull requests

Successful merges:

rust-lang#130824 (Add missing module flags for -Zfunction-return=thunk-extern)
rust-lang#131170 (Fix target_vendor in non-IDF Xtensa ESP32 targets)
rust-lang#131369 (Update books)
rust-lang#131370 (rustdoc: improve <wbr>-insertion for SCREAMING_CAMEL_CASE)

r? @ghost @rustbot modify labels: rollup

bors added a commit to rust-lang-ci/rust that referenced this pull request

Oct 8, 2024

rust-timer added a commit to rust-lang-ci/rust that referenced this pull request

Oct 8, 2024

LorenzoBianconi pushed a commit to LorenzoBianconi/linux-pinctrl that referenced this pull request

Nov 3, 2024

When enabling both KASAN and RETHUNK, objtool emits the following warnings:

rust/core.o: warning: objtool: asan.module_ctor+0x13: 'naked' return found in MITIGATION_RETHUNK build
rust/core.o: warning: objtool: asan.module_dtor+0x13: 'naked' return found in MITIGATION_RETHUNK build

The other mitigations that we enabled for Rust (SLS, RETPOLINE) do not have the same bug, as they're being applied through the target-feature functionality instead.

This is being fixed for rustc 1.83.0, so update Kconfig to reject this configuration on older compilers.

Labels

A-rust-for-linux

Relevant for the Rust-for-Linux project

S-waiting-on-bors

Status: Waiting on bors to run and complete tests. Bors will change the label on completion.

T-compiler

Relevant to the compiler team, which will review and decide on the PR/issue.

Add missing module flags for -Zfunction-return=thunk-extern by Darksonn · Pull Request #130824 · rust-lang/rust (original) (raw)

Conversation

Choose a reason for hiding this comment

Add missing module flags for `-Zfunction-return=thunk-extern` by Darksonn · Pull Request #130824 · rust-lang/rust (original) (raw)