| Message ID | 20250210-acpi-platform_profile-fix-cfi-violation-v3-1-ed9e9901c33a@kernel.org (mailing list archive) |
|---|---|
| State | Queued |
| Delegated to: | Rafael Wysocki |
| Headers | show |
| Series | [v3] ACPI: platform-profile: Fix CFI violation when accessing sysfs files | expand |
On Mon, Feb 10, 2025 at 09:28:25PM -0500, Nathan Chancellor wrote: > When an attribute group is created with sysfs_create_group(), the > ->sysfs_ops() callback is set to kobj_sysfs_ops, which sets the ->show() > and ->store() callbacks to kobj_attr_show() and kobj_attr_store() > respectively. These functions use container_of() to get the respective > callback from the passed attribute, meaning that these callbacks need to > be the same type as the callbacks in 'struct kobj_attribute'. > > However, the platform_profile sysfs functions have the type of the > ->show() and ->store() callbacks in 'struct device_attribute', which > results a CFI violation when accessing platform_profile or > platform_profile_choices under /sys/firmware/acpi because the types do > not match: > > CFI failure at kobj_attr_show+0x19/0x30 (target: platform_profile_choices_show+0x0/0x140; expected type: 0x7a69590c) > > There is no functional issue from the type mismatch because the layout > of 'struct kobj_attribute' and 'struct device_attribute' are the same, > so the container_of() cast does not break anything aside from CFI. > > Change the type of platform_profile_choices_show() and > platform_profile_{show,store}() to match the callbacks in > 'struct kobj_attribute' and update the attribute variables to match, > which resolves the CFI violation. Nice catch. > Cc: stable@vger.kernel.org > Fixes: a2ff95e018f1 ("ACPI: platform: Add platform profile support") > Reported-by: John Rowley <lkml@johnrowley.me> > Closes: https://github.com/ClangBuiltLinux/linux/issues/2047 > Tested-by: John Rowley <lkml@johnrowley.me> > Reviewed-by: Sami Tolvanen <samitolvanen@google.com> > Signed-off-by: Nathan Chancellor <nathan@kernel.org> > --- > Changes in v3: > - Rebase on 6.14-rc1, which includes updates to the driver to address > Greg's previous concerns but this change is still needed for the > legacy sysfs interface. v2 can be used for the stable backport. > - Link to v2: https://lore.kernel.org/r/20241118-acpi-platform_profile-fix-cfi-violation-v2-1-62ff952804de@kernel.org I'll never find that, so be prepared for a "FAILED" email when this hits Linus's tree :) Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Hi Nathan On Mon, Feb 10, 2025, at 9:28 PM, Nathan Chancellor wrote: > When an attribute group is created with sysfs_create_group(), the > ->sysfs_ops() callback is set to kobj_sysfs_ops, which sets the ->show() > and ->store() callbacks to kobj_attr_show() and kobj_attr_store() > respectively. These functions use container_of() to get the respective > callback from the passed attribute, meaning that these callbacks need to > be the same type as the callbacks in 'struct kobj_attribute'. > > However, the platform_profile sysfs functions have the type of the > ->show() and ->store() callbacks in 'struct device_attribute', which > results a CFI violation when accessing platform_profile or > platform_profile_choices under /sys/firmware/acpi because the types do > not match: > > CFI failure at kobj_attr_show+0x19/0x30 (target: > platform_profile_choices_show+0x0/0x140; expected type: 0x7a69590c) > > There is no functional issue from the type mismatch because the layout > of 'struct kobj_attribute' and 'struct device_attribute' are the same, > so the container_of() cast does not break anything aside from CFI. > > Change the type of platform_profile_choices_show() and > platform_profile_{show,store}() to match the callbacks in > 'struct kobj_attribute' and update the attribute variables to match, > which resolves the CFI violation. > > Cc: stable@vger.kernel.org > Fixes: a2ff95e018f1 ("ACPI: platform: Add platform profile support") > Reported-by: John Rowley <lkml@johnrowley.me> > Closes: https://github.com/ClangBuiltLinux/linux/issues/2047 > Tested-by: John Rowley <lkml@johnrowley.me> > Reviewed-by: Sami Tolvanen <samitolvanen@google.com> > Signed-off-by: Nathan Chancellor <nathan@kernel.org> > --- > Changes in v3: > - Rebase on 6.14-rc1, which includes updates to the driver to address > Greg's previous concerns but this change is still needed for the > legacy sysfs interface. v2 can be used for the stable backport. > - Link to v2: > https://lore.kernel.org/r/20241118-acpi-platform_profile-fix-cfi-violation-v2-1-62ff952804de@kernel.org > > Changes in v2: > - Rebase on linux-pm/acpi > - Pick up Sami's reviewed-by tag > - Adjust wording around why there is no functional issue from the > mismatched types > - Link to v1: > https://lore.kernel.org/r/20240819-acpi-platform_profile-fix-cfi-violation-v1-1-479365d848f6@kernel.org > --- > drivers/acpi/platform_profile.c | 26 +++++++++++++------------- > 1 file changed, 13 insertions(+), 13 deletions(-) > > diff --git a/drivers/acpi/platform_profile.c > b/drivers/acpi/platform_profile.c > index fc92e43d0fe9..1b6317f759f9 100644 > --- a/drivers/acpi/platform_profile.c > +++ b/drivers/acpi/platform_profile.c > @@ -260,14 +260,14 @@ static int _aggregate_choices(struct device *dev, > void *data) > > /** > * platform_profile_choices_show - Show the available profile choices > for legacy sysfs interface > - * @dev: The device > + * @kobj: The kobject > * @attr: The attribute > * @buf: The buffer to write to > * > * Return: The number of bytes written > */ > -static ssize_t platform_profile_choices_show(struct device *dev, > - struct device_attribute *attr, > +static ssize_t platform_profile_choices_show(struct kobject *kobj, > + struct kobj_attribute *attr, > char *buf) > { > unsigned long aggregate[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)]; > @@ -333,14 +333,14 @@ static int _store_and_notify(struct device *dev, > void *data) > > /** > * platform_profile_show - Show the current profile for legacy sysfs interface > - * @dev: The device > + * @kobj: The kobject > * @attr: The attribute > * @buf: The buffer to write to > * > * Return: The number of bytes written > */ > -static ssize_t platform_profile_show(struct device *dev, > - struct device_attribute *attr, > +static ssize_t platform_profile_show(struct kobject *kobj, > + struct kobj_attribute *attr, > char *buf) > { > enum platform_profile_option profile = PLATFORM_PROFILE_LAST; > @@ -362,15 +362,15 @@ static ssize_t platform_profile_show(struct device *dev, > > /** > * platform_profile_store - Set the profile for legacy sysfs interface > - * @dev: The device > + * @kobj: The kobject > * @attr: The attribute > * @buf: The buffer to read from > * @count: The number of bytes to read > * > * Return: The number of bytes read > */ > -static ssize_t platform_profile_store(struct device *dev, > - struct device_attribute *attr, > +static ssize_t platform_profile_store(struct kobject *kobj, > + struct kobj_attribute *attr, > const char *buf, size_t count) > { > unsigned long choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)]; > @@ -401,12 +401,12 @@ static ssize_t platform_profile_store(struct device *dev, > return count; > } > > -static DEVICE_ATTR_RO(platform_profile_choices); > -static DEVICE_ATTR_RW(platform_profile); > +static struct kobj_attribute attr_platform_profile_choices = > __ATTR_RO(platform_profile_choices); > +static struct kobj_attribute attr_platform_profile = > __ATTR_RW(platform_profile); > > static struct attribute *platform_profile_attrs[] = { > - &dev_attr_platform_profile_choices.attr, > - &dev_attr_platform_profile.attr, > + &attr_platform_profile_choices.attr, > + &attr_platform_profile.attr, > NULL > }; > > > --- > base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b > change-id: 20240819-acpi-platform_profile-fix-cfi-violation-de278753bd5f > > Best regards, > -- > Nathan Chancellor <nathan@kernel.org> Just a note to say thank you for noticing my email address change - the old lenovo one was awful to use so I dropped it a while back, but it meant I missed your first two patches (my mail filters for the list should have caught it and I'll have to figure out why not...) From the V1 patch there was a question about why it was done this way: I believe I just copied how it seems to be done everywhere else in the kernel. I can't remember what I used as a reference exactly, but I went and checked a few random drivers and it seems to be everywhere. Patch looks fine (I'd like to try it out on my system - will aim to do that today). I didn't know what CFI was (and have lightly educated myself now). Is there a better way to fix this so it's common across all drivers somehow? Updating every individual instance is going to be a lot. Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca> Mark
On Tue, Feb 11, 2025, at 10:05 AM, Mark Pearson wrote: > Hi Nathan > > On Mon, Feb 10, 2025, at 9:28 PM, Nathan Chancellor wrote: >> When an attribute group is created with sysfs_create_group(), the >> ->sysfs_ops() callback is set to kobj_sysfs_ops, which sets the ->show() >> and ->store() callbacks to kobj_attr_show() and kobj_attr_store() >> respectively. These functions use container_of() to get the respective >> callback from the passed attribute, meaning that these callbacks need to >> be the same type as the callbacks in 'struct kobj_attribute'. >> >> However, the platform_profile sysfs functions have the type of the >> ->show() and ->store() callbacks in 'struct device_attribute', which >> results a CFI violation when accessing platform_profile or >> platform_profile_choices under /sys/firmware/acpi because the types do >> not match: >> >> CFI failure at kobj_attr_show+0x19/0x30 (target: >> platform_profile_choices_show+0x0/0x140; expected type: 0x7a69590c) >> >> There is no functional issue from the type mismatch because the layout >> of 'struct kobj_attribute' and 'struct device_attribute' are the same, >> so the container_of() cast does not break anything aside from CFI. >> >> Change the type of platform_profile_choices_show() and >> platform_profile_{show,store}() to match the callbacks in >> 'struct kobj_attribute' and update the attribute variables to match, >> which resolves the CFI violation. >> >> Cc: stable@vger.kernel.org >> Fixes: a2ff95e018f1 ("ACPI: platform: Add platform profile support") >> Reported-by: John Rowley <lkml@johnrowley.me> >> Closes: https://github.com/ClangBuiltLinux/linux/issues/2047 >> Tested-by: John Rowley <lkml@johnrowley.me> >> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> >> Signed-off-by: Nathan Chancellor <nathan@kernel.org> >> --- >> Changes in v3: >> - Rebase on 6.14-rc1, which includes updates to the driver to address >> Greg's previous concerns but this change is still needed for the >> legacy sysfs interface. v2 can be used for the stable backport. >> - Link to v2: >> https://lore.kernel.org/r/20241118-acpi-platform_profile-fix-cfi-violation-v2-1-62ff952804de@kernel.org >> >> Changes in v2: >> - Rebase on linux-pm/acpi >> - Pick up Sami's reviewed-by tag >> - Adjust wording around why there is no functional issue from the >> mismatched types >> - Link to v1: >> https://lore.kernel.org/r/20240819-acpi-platform_profile-fix-cfi-violation-v1-1-479365d848f6@kernel.org >> --- >> drivers/acpi/platform_profile.c | 26 +++++++++++++------------- >> 1 file changed, 13 insertions(+), 13 deletions(-) >> >> diff --git a/drivers/acpi/platform_profile.c >> b/drivers/acpi/platform_profile.c >> index fc92e43d0fe9..1b6317f759f9 100644 >> --- a/drivers/acpi/platform_profile.c >> +++ b/drivers/acpi/platform_profile.c >> @@ -260,14 +260,14 @@ static int _aggregate_choices(struct device *dev, >> void *data) >> >> /** >> * platform_profile_choices_show - Show the available profile choices >> for legacy sysfs interface >> - * @dev: The device >> + * @kobj: The kobject >> * @attr: The attribute >> * @buf: The buffer to write to >> * >> * Return: The number of bytes written >> */ >> -static ssize_t platform_profile_choices_show(struct device *dev, >> - struct device_attribute *attr, >> +static ssize_t platform_profile_choices_show(struct kobject *kobj, >> + struct kobj_attribute *attr, >> char *buf) >> { >> unsigned long aggregate[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)]; >> @@ -333,14 +333,14 @@ static int _store_and_notify(struct device *dev, >> void *data) >> >> /** >> * platform_profile_show - Show the current profile for legacy sysfs interface >> - * @dev: The device >> + * @kobj: The kobject >> * @attr: The attribute >> * @buf: The buffer to write to >> * >> * Return: The number of bytes written >> */ >> -static ssize_t platform_profile_show(struct device *dev, >> - struct device_attribute *attr, >> +static ssize_t platform_profile_show(struct kobject *kobj, >> + struct kobj_attribute *attr, >> char *buf) >> { >> enum platform_profile_option profile = PLATFORM_PROFILE_LAST; >> @@ -362,15 +362,15 @@ static ssize_t platform_profile_show(struct device *dev, >> >> /** >> * platform_profile_store - Set the profile for legacy sysfs interface >> - * @dev: The device >> + * @kobj: The kobject >> * @attr: The attribute >> * @buf: The buffer to read from >> * @count: The number of bytes to read >> * >> * Return: The number of bytes read >> */ >> -static ssize_t platform_profile_store(struct device *dev, >> - struct device_attribute *attr, >> +static ssize_t platform_profile_store(struct kobject *kobj, >> + struct kobj_attribute *attr, >> const char *buf, size_t count) >> { >> unsigned long choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)]; >> @@ -401,12 +401,12 @@ static ssize_t platform_profile_store(struct device *dev, >> return count; >> } >> >> -static DEVICE_ATTR_RO(platform_profile_choices); >> -static DEVICE_ATTR_RW(platform_profile); >> +static struct kobj_attribute attr_platform_profile_choices = >> __ATTR_RO(platform_profile_choices); >> +static struct kobj_attribute attr_platform_profile = >> __ATTR_RW(platform_profile); >> >> static struct attribute *platform_profile_attrs[] = { >> - &dev_attr_platform_profile_choices.attr, >> - &dev_attr_platform_profile.attr, >> + &attr_platform_profile_choices.attr, >> + &attr_platform_profile.attr, >> NULL >> }; >> >> >> --- >> base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b >> change-id: 20240819-acpi-platform_profile-fix-cfi-violation-de278753bd5f >> >> Best regards, >> -- >> Nathan Chancellor <nathan@kernel.org> > > Just a note to say thank you for noticing my email address change - the > old lenovo one was awful to use so I dropped it a while back, but it > meant I missed your first two patches (my mail filters for the list > should have caught it and I'll have to figure out why not...) > > From the V1 patch there was a question about why it was done this way: > I believe I just copied how it seems to be done everywhere else in the > kernel. I can't remember what I used as a reference exactly, but I went > and checked a few random drivers and it seems to be everywhere. > > Patch looks fine (I'd like to try it out on my system - will aim to do > that today). I didn't know what CFI was (and have lightly educated > myself now). > Is there a better way to fix this so it's common across all drivers > somehow? Updating every individual instance is going to be a lot. > > Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca> > Also: Tested-by: Mark Pearson <mpearson-lenovo@squebb.ca> Mark
Hi Mark, On Tue, Feb 11, 2025 at 10:05:18AM -0500, Mark Pearson wrote: > Just a note to say thank you for noticing my email address change - > the old lenovo one was awful to use so I dropped it a while back, but > it meant I missed your first two patches (my mail filters for the list > should have caught it and I'll have to figure out why not...) No worries, I totally get that. It may be good to update the few places in the kernel that still use your Lenovo address but I understand if there are other reasons to keep it around. .mailmap could also help too. > Patch looks fine (I'd like to try it out on my system - will aim to do > that today). I didn't know what CFI was (and have lightly educated > myself now). Is there a better way to fix this so it's common across > all drivers somehow? Updating every individual instance is going to be > a lot. This does not happen all too often as far as I can tell. I have only sent a handful of these patches over the past couple of years since CFI was officially merged. Due to the way these sysfs interfaces work, I am not sure this can really be fixed at a grand scale. Cheers, Nathan
On Tue, Feb 11, 2025 at 3:28 AM Nathan Chancellor <nathan@kernel.org> wrote: > > When an attribute group is created with sysfs_create_group(), the > ->sysfs_ops() callback is set to kobj_sysfs_ops, which sets the ->show() > and ->store() callbacks to kobj_attr_show() and kobj_attr_store() > respectively. These functions use container_of() to get the respective > callback from the passed attribute, meaning that these callbacks need to > be the same type as the callbacks in 'struct kobj_attribute'. > > However, the platform_profile sysfs functions have the type of the > ->show() and ->store() callbacks in 'struct device_attribute', which > results a CFI violation when accessing platform_profile or > platform_profile_choices under /sys/firmware/acpi because the types do > not match: > > CFI failure at kobj_attr_show+0x19/0x30 (target: platform_profile_choices_show+0x0/0x140; expected type: 0x7a69590c) > > There is no functional issue from the type mismatch because the layout > of 'struct kobj_attribute' and 'struct device_attribute' are the same, > so the container_of() cast does not break anything aside from CFI. > > Change the type of platform_profile_choices_show() and > platform_profile_{show,store}() to match the callbacks in > 'struct kobj_attribute' and update the attribute variables to match, > which resolves the CFI violation. > > Cc: stable@vger.kernel.org > Fixes: a2ff95e018f1 ("ACPI: platform: Add platform profile support") > Reported-by: John Rowley <lkml@johnrowley.me> > Closes: https://github.com/ClangBuiltLinux/linux/issues/2047 > Tested-by: John Rowley <lkml@johnrowley.me> > Reviewed-by: Sami Tolvanen <samitolvanen@google.com> > Signed-off-by: Nathan Chancellor <nathan@kernel.org> > --- > Changes in v3: > - Rebase on 6.14-rc1, which includes updates to the driver to address > Greg's previous concerns but this change is still needed for the > legacy sysfs interface. v2 can be used for the stable backport. > - Link to v2: https://lore.kernel.org/r/20241118-acpi-platform_profile-fix-cfi-violation-v2-1-62ff952804de@kernel.org > > Changes in v2: > - Rebase on linux-pm/acpi > - Pick up Sami's reviewed-by tag > - Adjust wording around why there is no functional issue from the > mismatched types > - Link to v1: https://lore.kernel.org/r/20240819-acpi-platform_profile-fix-cfi-violation-v1-1-479365d848f6@kernel.org > --- > drivers/acpi/platform_profile.c | 26 +++++++++++++------------- > 1 file changed, 13 insertions(+), 13 deletions(-) > > diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c > index fc92e43d0fe9..1b6317f759f9 100644 > --- a/drivers/acpi/platform_profile.c > +++ b/drivers/acpi/platform_profile.c > @@ -260,14 +260,14 @@ static int _aggregate_choices(struct device *dev, void *data) > > /** > * platform_profile_choices_show - Show the available profile choices for legacy sysfs interface > - * @dev: The device > + * @kobj: The kobject > * @attr: The attribute > * @buf: The buffer to write to > * > * Return: The number of bytes written > */ > -static ssize_t platform_profile_choices_show(struct device *dev, > - struct device_attribute *attr, > +static ssize_t platform_profile_choices_show(struct kobject *kobj, > + struct kobj_attribute *attr, > char *buf) > { > unsigned long aggregate[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)]; > @@ -333,14 +333,14 @@ static int _store_and_notify(struct device *dev, void *data) > > /** > * platform_profile_show - Show the current profile for legacy sysfs interface > - * @dev: The device > + * @kobj: The kobject > * @attr: The attribute > * @buf: The buffer to write to > * > * Return: The number of bytes written > */ > -static ssize_t platform_profile_show(struct device *dev, > - struct device_attribute *attr, > +static ssize_t platform_profile_show(struct kobject *kobj, > + struct kobj_attribute *attr, > char *buf) > { > enum platform_profile_option profile = PLATFORM_PROFILE_LAST; > @@ -362,15 +362,15 @@ static ssize_t platform_profile_show(struct device *dev, > > /** > * platform_profile_store - Set the profile for legacy sysfs interface > - * @dev: The device > + * @kobj: The kobject > * @attr: The attribute > * @buf: The buffer to read from > * @count: The number of bytes to read > * > * Return: The number of bytes read > */ > -static ssize_t platform_profile_store(struct device *dev, > - struct device_attribute *attr, > +static ssize_t platform_profile_store(struct kobject *kobj, > + struct kobj_attribute *attr, > const char *buf, size_t count) > { > unsigned long choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)]; > @@ -401,12 +401,12 @@ static ssize_t platform_profile_store(struct device *dev, > return count; > } > > -static DEVICE_ATTR_RO(platform_profile_choices); > -static DEVICE_ATTR_RW(platform_profile); > +static struct kobj_attribute attr_platform_profile_choices = __ATTR_RO(platform_profile_choices); > +static struct kobj_attribute attr_platform_profile = __ATTR_RW(platform_profile); > > static struct attribute *platform_profile_attrs[] = { > - &dev_attr_platform_profile_choices.attr, > - &dev_attr_platform_profile.attr, > + &attr_platform_profile_choices.attr, > + &attr_platform_profile.attr, > NULL > }; > > > --- Applied as 6.15 material with some edits in the changelog, thanks!
diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c index fc92e43d0fe9..1b6317f759f9 100644 --- a/drivers/acpi/platform_profile.c +++ b/drivers/acpi/platform_profile.c @@ -260,14 +260,14 @@ static int _aggregate_choices(struct device *dev, void *data) /** * platform_profile_choices_show - Show the available profile choices for legacy sysfs interface - * @dev: The device + * @kobj: The kobject * @attr: The attribute * @buf: The buffer to write to * * Return: The number of bytes written */ -static ssize_t platform_profile_choices_show(struct device *dev, - struct device_attribute *attr, +static ssize_t platform_profile_choices_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) { unsigned long aggregate[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)]; @@ -333,14 +333,14 @@ static int _store_and_notify(struct device *dev, void *data) /** * platform_profile_show - Show the current profile for legacy sysfs interface - * @dev: The device + * @kobj: The kobject * @attr: The attribute * @buf: The buffer to write to * * Return: The number of bytes written */ -static ssize_t platform_profile_show(struct device *dev, - struct device_attribute *attr, +static ssize_t platform_profile_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) { enum platform_profile_option profile = PLATFORM_PROFILE_LAST; @@ -362,15 +362,15 @@ static ssize_t platform_profile_show(struct device *dev, /** * platform_profile_store - Set the profile for legacy sysfs interface - * @dev: The device + * @kobj: The kobject * @attr: The attribute * @buf: The buffer to read from * @count: The number of bytes to read * * Return: The number of bytes read */ -static ssize_t platform_profile_store(struct device *dev, - struct device_attribute *attr, +static ssize_t platform_profile_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, size_t count) { unsigned long choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)]; @@ -401,12 +401,12 @@ static ssize_t platform_profile_store(struct device *dev, return count; } -static DEVICE_ATTR_RO(platform_profile_choices); -static DEVICE_ATTR_RW(platform_profile); +static struct kobj_attribute attr_platform_profile_choices = __ATTR_RO(platform_profile_choices); +static struct kobj_attribute attr_platform_profile = __ATTR_RW(platform_profile); static struct attribute *platform_profile_attrs[] = { - &dev_attr_platform_profile_choices.attr, - &dev_attr_platform_profile.attr, + &attr_platform_profile_choices.attr, + &attr_platform_profile.attr, NULL };
When an attribute group is created with sysfs_create_group(), the ->sysfs_ops() callback is set to kobj_sysfs_ops, which sets the ->show() and ->store() callbacks to kobj_attr_show() and kobj_attr_store() respectively. These functions use container_of() to get the respective callback from the passed attribute, meaning that these callbacks need to be the same type as the callbacks in 'struct kobj_attribute'. However, the platform_profile sysfs functions have the type of the ->show() and ->store() callbacks in 'struct device_attribute', which results a CFI violation when accessing platform_profile or platform_profile_choices under /sys/firmware/acpi because the types do not match: CFI failure at kobj_attr_show+0x19/0x30 (target: platform_profile_choices_show+0x0/0x140; expected type: 0x7a69590c) There is no functional issue from the type mismatch because the layout of 'struct kobj_attribute' and 'struct device_attribute' are the same, so the container_of() cast does not break anything aside from CFI. Change the type of platform_profile_choices_show() and platform_profile_{show,store}() to match the callbacks in 'struct kobj_attribute' and update the attribute variables to match, which resolves the CFI violation. Cc: stable@vger.kernel.org Fixes: a2ff95e018f1 ("ACPI: platform: Add platform profile support") Reported-by: John Rowley <lkml@johnrowley.me> Closes: https://github.com/ClangBuiltLinux/linux/issues/2047 Tested-by: John Rowley <lkml@johnrowley.me> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> --- Changes in v3: - Rebase on 6.14-rc1, which includes updates to the driver to address Greg's previous concerns but this change is still needed for the legacy sysfs interface. v2 can be used for the stable backport. - Link to v2: https://lore.kernel.org/r/20241118-acpi-platform_profile-fix-cfi-violation-v2-1-62ff952804de@kernel.org Changes in v2: - Rebase on linux-pm/acpi - Pick up Sami's reviewed-by tag - Adjust wording around why there is no functional issue from the mismatched types - Link to v1: https://lore.kernel.org/r/20240819-acpi-platform_profile-fix-cfi-violation-v1-1-479365d848f6@kernel.org --- drivers/acpi/platform_profile.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) --- base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b change-id: 20240819-acpi-platform_profile-fix-cfi-violation-de278753bd5f Best regards,