[PATCH v3] x86/pci: fix the function type for check_reserved_t

[PATCH v3] x86/pci: fix the function type for check_reserved_t

[Sami Tolvanen]

e820__mapped_all is passed as a callback to is_mmconf_reserved,
which expects a function of type:

typedef bool (*check_reserved_t)(u64 start, u64 end, unsigned type);

However, e820__mapped_all accepts enum e820_type as the last
argument and this type mismatch trips indirect call checking with
Clang's Control-Flow Integrity (CFI).

As is_mmconf_reserved only passes enum e820_type values for the
type argument, change the typedef and the unused type argument in
is_acpi_reserved to enum e820_type to fix the type mismatch.

Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 arch/x86/pci/mmconfig-shared.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 6fa42e9c4e6f..234998f196d4 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -425,7 +425,7 @@ static acpi_status find_mboard_resource(acpi_handle handle, u32 lvl,
 	return AE_OK;
 }
 
-static bool is_acpi_reserved(u64 start, u64 end, unsigned not_used)
+static bool is_acpi_reserved(u64 start, u64 end, enum e820_type not_used)
 {
 	struct resource mcfg_res;
 
@@ -442,7 +442,7 @@ static bool is_acpi_reserved(u64 start, u64 end, unsigned not_used)
 	return mcfg_res.flags;
 }
 
-typedef bool (*check_reserved_t)(u64 start, u64 end, unsigned type);
+typedef bool (*check_reserved_t)(u64 start, u64 end, enum e820_type type);
 
 static bool __ref is_mmconf_reserved(check_reserved_t is_reserved,
 				     struct pci_mmcfg_region *cfg,

base-commit: b65054597872ce3aefbc6a666385eabdf9e288da
-- 
2.29.2.454.gaff20da3a2-goog

[tip: x86/misc] x86/pci: Fix the function type for check_reserved_t

[tip-bot2 for Sami Tolvanen]

The following commit has been merged into the x86/misc branch of tip:

Commit-ID:     83321c335dccba262a57378361d63da96b8166d6
Gitweb:        https://git.kernel.org/tip/83321c335dccba262a57378361d63da96b8166d6
Author:        Sami Tolvanen <samitolvanen@google.com>
AuthorDate:    Mon, 30 Nov 2020 11:39:00 -08:00
Committer:     Borislav Petkov <bp@suse.de>
CommitterDate: Tue, 01 Dec 2020 14:22:52 +01:00

x86/pci: Fix the function type for check_reserved_t

e820__mapped_all() is passed as a callback to is_mmconf_reserved(),
which expects a function of type:

  typedef bool (*check_reserved_t)(u64 start, u64 end, unsigned type);

However, e820__mapped_all() accepts enum e820_type as the last argument
and this type mismatch trips indirect call checking with Clang's
Control-Flow Integrity (CFI).

As is_mmconf_reserved() only passes enum e820_type values for the
type argument, change the typedef and the unused type argument in
is_acpi_reserved() to enum e820_type to fix the type mismatch.

Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20201130193900.456726-1-samitolvanen@google.com
---
 arch/x86/pci/mmconfig-shared.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 6fa42e9..234998f 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -425,7 +425,7 @@ static acpi_status find_mboard_resource(acpi_handle handle, u32 lvl,
 	return AE_OK;
 }
 
-static bool is_acpi_reserved(u64 start, u64 end, unsigned not_used)
+static bool is_acpi_reserved(u64 start, u64 end, enum e820_type not_used)
 {
 	struct resource mcfg_res;
 
@@ -442,7 +442,7 @@ static bool is_acpi_reserved(u64 start, u64 end, unsigned not_used)
 	return mcfg_res.flags;
 }
 
-typedef bool (*check_reserved_t)(u64 start, u64 end, unsigned type);
+typedef bool (*check_reserved_t)(u64 start, u64 end, enum e820_type type);
 
 static bool __ref is_mmconf_reserved(check_reserved_t is_reserved,
 				     struct pci_mmcfg_region *cfg,

Re: [PATCH v3] x86/pci: fix the function type for check_reserved_t

[Kees Cook]

On Mon, Nov 30, 2020 at 11:39:00AM -0800, Sami Tolvanen wrote:
> e820__mapped_all is passed as a callback to is_mmconf_reserved,
> which expects a function of type:
> 
> typedef bool (*check_reserved_t)(u64 start, u64 end, unsigned type);
> 
> However, e820__mapped_all accepts enum e820_type as the last
> argument and this type mismatch trips indirect call checking with
> Clang's Control-Flow Integrity (CFI).
> 
> As is_mmconf_reserved only passes enum e820_type values for the
> type argument, change the typedef and the unused type argument in
> is_acpi_reserved to enum e820_type to fix the type mismatch.
> 
> Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
> Suggested-by: Borislav Petkov <bp@alien8.de>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

Re: [PATCH v3] x86/pci: fix the function type for check_reserved_t

[Sedat Dilek]

On Wed, Dec 2, 2020 at 8:39 PM Kees Cook <keescook@chromium.org> wrote:
>
> On Mon, Nov 30, 2020 at 11:39:00AM -0800, Sami Tolvanen wrote:
> > e820__mapped_all is passed as a callback to is_mmconf_reserved,
> > which expects a function of type:
> >
> > typedef bool (*check_reserved_t)(u64 start, u64 end, unsigned type);
> >
> > However, e820__mapped_all accepts enum e820_type as the last
> > argument and this type mismatch trips indirect call checking with
> > Clang's Control-Flow Integrity (CFI).
> >
> > As is_mmconf_reserved only passes enum e820_type values for the
> > type argument, change the typedef and the unused type argument in
> > is_acpi_reserved to enum e820_type to fix the type mismatch.
> >
> > Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
> > Suggested-by: Borislav Petkov <bp@alien8.de>
> > Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
>

Hi Sami,

Back from a time-out...

Please add my:

Tested-by: Sedat Dilek <sedat.dilek@gmail.com>

I have some other patches which I had reported when testing Clang-CFI
against Linux v5.9 which misses my Tested-by.
I know we did all that reporting and testing via private email, so it
is as it is.
Reported-by is half-done...

Thanks.

Regards,
- Sedat -