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samitolvanen opened this issue Oct 19, 2022 · 9 comments
Closed

CFI: asan.module_ctor is missing a type hash #1742

samitolvanen opened this issue Oct 19, 2022 · 9 comments
Labels
[BUG] llvm (main) A bug in an unreleased version of LLVM (this label is appropriate for regressions) [FEATURE] CFI Related to building the kernel with Clang Control Flow Integrity [FIXED][LINUX] 6.2 This bug was fixed in Linux 6.2 [FIXED][LLVM] main This bug was only present and fixed in an unreleased version of LLVM

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@samitolvanen
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From Mark Rutland:

Looks like CFI && KASAN is borked on both arm64 and x86; the implicitly-generated asan.module_ctor functions aren't given a type hash by the compiler, so when those get invoked by do_ctors() the calls fail

cc @kees @nickdesaulniers @nathanchance @lvwr
@samitolvanen samitolvanen added [FEATURE] CFI Related to building the kernel with Clang Control Flow Integrity [BUG] llvm (main) A bug in an unreleased version of LLVM (this label is appropriate for regressions) labels Oct 19, 2022
@samitolvanen samitolvanen changed the title CFI: asan.* functions are missing type hashes CFI: asan.module_ctor is missing a type hash Oct 19, 2022
@samitolvanen
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The asan.module_ctor function is created in the asan LLVM pass using createSanitizerCtor. Since this happens outside of Clang, it's a bit awkward to generate a type hash for the function at this point.

The reason we didn't have this problem earlier was that do_ctors is an __init function and CFI was disabled for it. I'm leaning towards simply marking the function __nocfi instead of hardcoding a type hash for these functions or hacking something together in LLVM to compute a hash. Thoughts?

@samitolvanen
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Perhaps setting the types in LLVM is reasonable after all, as we'd have to deal with module constructors as well otherwise. Here's an alternative solution: https://reviews.llvm.org/D138945

samitolvanen added a commit to samitolvanen/llvm-project that referenced this issue Dec 8, 2022
@samitolvanen
[ModuleUtils][KCFI] Set !kcfi_type metadata for sanitizer constructors
6d8ca6f 
Set KCFI type metadata for the sanitizer constructors to prevent
runtime failures when these functions are indirectly called in
instrumented code. This fixes a compatibility issue with KASAN and
-fsanitize=kcfi in the Linux kernel.

Link: ClangBuiltLinux/linux#1742

Differential Revision: https://reviews.llvm.org/D138945
samitolvanen added a commit to llvm/llvm-project that referenced this issue Dec 9, 2022
@samitolvanen
[ModuleUtils][KCFI] Set !kcfi_type metadata for sanitizer constructors
3b14862 
Set KCFI type metadata for the sanitizer constructors to prevent
runtime failures when these functions are indirectly called in
instrumented code. This fixes a compatibility issue with KASAN and
-fsanitize=kcfi in the Linux kernel.

Link: ClangBuiltLinux/linux#1742

Reviewed By: nickdesaulniers, MaskRay

Differential Revision: https://reviews.llvm.org/D138945
@samitolvanen
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The remaining issue with CFI+KASAN is that asan.module_ctor still won't have a type hash in object files that were not compiled with -fsanitize=kcfi. With x86/arm64 defconfigs, it looks like only the constructor in kernel/cfi.o trips KASAN, but I don't see any reason we couldn't now enable CFI also for kernel/cfi.c.

intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Dec 22, 2022
@samitolvanen @intel-lab-lkp
cfi: Fix CFI failure with KASAN
9f83c20 
When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
@samitolvanen
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https://lore.kernel.org/lkml/[email protected]/

torvalds pushed a commit to torvalds/linux that referenced this issue Dec 23, 2022
@samitolvanen @kees
cfi: Fix CFI failure with KASAN
cf80164 
When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 27, 2022
@samitolvanen
cfi: Fix CFI failure with KASAN
96bc8c3 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 27, 2022
@samitolvanen
cfi: Fix CFI failure with KASAN
b00e069 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 27, 2022
@samitolvanen
cfi: Fix CFI failure with KASAN
af1c16a 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 27, 2022
@samitolvanen @gregkh
cfi: Fix CFI failure with KASAN
8e3882a 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 27, 2022
@samitolvanen
cfi: Fix CFI failure with KASAN
8db593b 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 27, 2022
@samitolvanen
cfi: Fix CFI failure with KASAN
6b301d9 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 27, 2022
@samitolvanen
cfi: Fix CFI failure with KASAN
f0c844a 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 27, 2022
@samitolvanen
cfi: Fix CFI failure with KASAN
d6cdd68 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 28, 2022
@samitolvanen
cfi: Fix CFI failure with KASAN
f4ac08d 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 28, 2022
@samitolvanen
cfi: Fix CFI failure with KASAN
4d2bec9 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 28, 2022
@samitolvanen
cfi: Fix CFI failure with KASAN
f31f9d6 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 28, 2022
@samitolvanen @gregkh
cfi: Fix CFI failure with KASAN
409ff88 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 28, 2022
@samitolvanen
cfi: Fix CFI failure with KASAN
97b77a1 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 28, 2022
@samitolvanen
cfi: Fix CFI failure with KASAN
9cb9eb4 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 pushed a commit to ammarfaizi2/linux-block that referenced this issue Dec 28, 2022
@samitolvanen @gregkh
cfi: Fix CFI failure with KASAN
77479f1 
[ Upstream commit cf80164 ]

When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a
CFI type hash for asan.module_ctor functions in translation units
where CFI is disabled, which leads to a CFI failure during boot when
do_ctors calls the affected constructors:

  CFI failure at do_basic_setup+0x64/0x90 (target:
  asan.module_ctor+0x0/0x28; expected type: 0xa540670c)

Specifically, this happens because CFI is disabled for
kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so
fix the failure by not filtering out CC_FLAGS_CFI for the file.

Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue
where LLVM didn't emit CFI type hashes for any sanitizer constructors,
but now type hashes are emitted correctly for TUs that use CFI.

Link: ClangBuiltLinux/linux#1742
Fixes: 8924560 ("cfi: Switch to -fsanitize=kcfi")
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
veselypeta pushed a commit to veselypeta/cherillvm that referenced this issue Jun 6, 2024
@samitolvanen @veselypeta
[ModuleUtils][KCFI] Set !kcfi_type metadata for sanitizer constructors
26daaec 
Set KCFI type metadata for the sanitizer constructors to prevent
runtime failures when these functions are indirectly called in
instrumented code. This fixes a compatibility issue with KASAN and
-fsanitize=kcfi in the Linux kernel.

Link: ClangBuiltLinux/linux#1742

Reviewed By: nickdesaulniers, MaskRay

Differential Revision: https://reviews.llvm.org/D138945
veselypeta pushed a commit to veselypeta/cherillvm that referenced this issue Jun 12, 2024
@samitolvanen @veselypeta
[ModuleUtils][KCFI] Set patchable-function-prefix for synthesized fun…
fc6a183 
…ctions

When -fpatchable-function-entry is used to emit prefix nops
before functions, KCFI assumes all indirectly called functions
have the same number of prefix nops, because the nops are emitted
between the KCFI type hash and the function entry. However, as
patchable-function-prefix is a function attribute set by Clang,
functions later synthesized by LLVM don't inherit this attribute
and end up not having prefix nops. One of these functions
is asan.module_ctor, which the Linux kernel ends up calling
indirectly when KASAN is enabled.

In order to avoid tripping KCFI, save the expected prefix offset
to a module flag, and use it when we're setting KCFI type for the
relevant synthesized functions.

Link: ClangBuiltLinux/linux#1742

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D141172
@scottconstable scottconstable mentioned this issue Nov 23, 2024
Open
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
18635ff 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
431a9bf 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
80380a3 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
1987c38 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
3839fca 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
9f499c2 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
53832a6 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
3bdaf16 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
03a3856 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
332f9ae 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
7437ed1 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
8afbd42 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
bd58734 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
ee55e84 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
151a7e6 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
59ebbed 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
eaca81d 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
069c8a3 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
6ebf0b1 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
2d275c2 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
4af480e 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
a306990 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
9815c9b 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
3f85d26 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
9886ffc 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
3f3b3c7 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
hopez13 pushed a commit to hopez13/kernel-superproject that referenced this issue Dec 26, 2024
kleaf: gcov: Temporarily disable CFI_CLANG
dc785e6 
* This is causing crashes due to missing type hashes.
* This should be reverted when
ClangBuiltLinux/linux#1742 is fixed.

Bug: 264407394
Change-Id: Iba23815e321c25ec0ad6aa7c078c834031a34dc8
Signed-off-by: Ulises Mendez Martinez <[email protected]>
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[BUG] llvm (main) A bug in an unreleased version of LLVM (this label is appropriate for regressions) [FEATURE] CFI Related to building the kernel with Clang Control Flow Integrity [FIXED][LINUX] 6.2 This bug was fixed in Linux 6.2 [FIXED][LLVM] main This bug was only present and fixed in an unreleased version of LLVM
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@samitolvanen @nathanchance