fw_cfg_showrev() is called by an indirect call in kobj_attr_show(),
which violates clang's CFI checking because fw_cfg_showrev()'s second
parameter is 'struct attribute', whereas the ->show() member of 'struct
kobj_structure' expects the second parameter to be of type 'struct
kobj_attribute'.
$ cat /sys/firmware/qemu_fw_cfg/rev
3
$ dmesg | grep "CFI failure"
[ 26.016832] CFI failure (target: fw_cfg_showrev+0x0/0x8):
Fix this by converting fw_cfg_rev_attr to 'struct kobj_attribute' where
this would have been caught automatically by the incompatible pointer
types compiler warning. Update fw_cfg_showrev() accordingly.
Fixes: 75f3e8e47f38 ("firmware: introduce sysfs driver for QEMU's fw_cfg device")
Link: https://github.com/ClangBuiltLinux/linux/issues/1299
Signed-off-by: Nathan Chancellor <[email protected]>
---
drivers/firmware/qemu_fw_cfg.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
index 0078260fbabe..172c751a4f6c 100644
--- a/drivers/firmware/qemu_fw_cfg.c
+++ b/drivers/firmware/qemu_fw_cfg.c
@@ -299,15 +299,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
return 0;
}
-static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
+static ssize_t fw_cfg_showrev(struct kobject *k, struct kobj_attribute *a,
+ char *buf)
{
return sprintf(buf, "%u\n", fw_cfg_rev);
}
-static const struct {
- struct attribute attr;
- ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
-} fw_cfg_rev_attr = {
+static const struct kobj_attribute fw_cfg_rev_attr = {
.attr = { .name = "rev", .mode = S_IRUSR },
.show = fw_cfg_showrev,
};
base-commit: 92bf22614b21a2706f4993b278017e437f7785b3
--
2.30.1
Hi Nathan,
On Thu, Feb 11, 2021 at 11:43 AM Nathan Chancellor <[email protected]> wrote:
>
> fw_cfg_showrev() is called by an indirect call in kobj_attr_show(),
> which violates clang's CFI checking because fw_cfg_showrev()'s second
> parameter is 'struct attribute', whereas the ->show() member of 'struct
> kobj_structure' expects the second parameter to be of type 'struct
> kobj_attribute'.
>
> $ cat /sys/firmware/qemu_fw_cfg/rev
> 3
>
> $ dmesg | grep "CFI failure"
> [ 26.016832] CFI failure (target: fw_cfg_showrev+0x0/0x8):
>
> Fix this by converting fw_cfg_rev_attr to 'struct kobj_attribute' where
> this would have been caught automatically by the incompatible pointer
> types compiler warning. Update fw_cfg_showrev() accordingly.
>
> Fixes: 75f3e8e47f38 ("firmware: introduce sysfs driver for QEMU's fw_cfg device")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1299
> Signed-off-by: Nathan Chancellor <[email protected]>
Looks good to me. Thank you for sending the patch!
Reviewed-by: Sami Tolvanen <[email protected]>
Sami
Did this happen to get picked up already? EOM
On Thu, Feb 11, 2021 at 11:43 AM Nathan Chancellor <[email protected]> wrote:
>
> fw_cfg_showrev() is called by an indirect call in kobj_attr_show(),
> which violates clang's CFI checking because fw_cfg_showrev()'s second
> parameter is 'struct attribute', whereas the ->show() member of 'struct
> kobj_structure' expects the second parameter to be of type 'struct
> kobj_attribute'.
>
> $ cat /sys/firmware/qemu_fw_cfg/rev
> 3
>
> $ dmesg | grep "CFI failure"
> [ 26.016832] CFI failure (target: fw_cfg_showrev+0x0/0x8):
>
> Fix this by converting fw_cfg_rev_attr to 'struct kobj_attribute' where
> this would have been caught automatically by the incompatible pointer
> types compiler warning. Update fw_cfg_showrev() accordingly.
>
> Fixes: 75f3e8e47f38 ("firmware: introduce sysfs driver for QEMU's fw_cfg device")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1299
> Signed-off-by: Nathan Chancellor <[email protected]>
> ---
> drivers/firmware/qemu_fw_cfg.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> index 0078260fbabe..172c751a4f6c 100644
> --- a/drivers/firmware/qemu_fw_cfg.c
> +++ b/drivers/firmware/qemu_fw_cfg.c
> @@ -299,15 +299,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
> return 0;
> }
>
> -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
> +static ssize_t fw_cfg_showrev(struct kobject *k, struct kobj_attribute *a,
> + char *buf)
> {
> return sprintf(buf, "%u\n", fw_cfg_rev);
> }
>
> -static const struct {
> - struct attribute attr;
> - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
> -} fw_cfg_rev_attr = {
> +static const struct kobj_attribute fw_cfg_rev_attr = {
> .attr = { .name = "rev", .mode = S_IRUSR },
> .show = fw_cfg_showrev,
> };
>
> base-commit: 92bf22614b21a2706f4993b278017e437f7785b3
> --
> 2.30.1
>
> --
> You received this message because you are subscribed to the Google Groups "Clang Built Linux" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
> To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20210211194258.4137998-1-nathan%40kernel.org.
--
Thanks,
~Nick Desaulniers
On Mon, Feb 22, 2021 at 11:02:34AM -0800, Nick Desaulniers wrote:
> Did this happen to get picked up already? EOM
I have not gotten an email saying it has been picked up nor does it
appear to be in -next.
Cheers,
Nathan
> On Thu, Feb 11, 2021 at 11:43 AM Nathan Chancellor <[email protected]> wrote:
> >
> > fw_cfg_showrev() is called by an indirect call in kobj_attr_show(),
> > which violates clang's CFI checking because fw_cfg_showrev()'s second
> > parameter is 'struct attribute', whereas the ->show() member of 'struct
> > kobj_structure' expects the second parameter to be of type 'struct
> > kobj_attribute'.
> >
> > $ cat /sys/firmware/qemu_fw_cfg/rev
> > 3
> >
> > $ dmesg | grep "CFI failure"
> > [ 26.016832] CFI failure (target: fw_cfg_showrev+0x0/0x8):
> >
> > Fix this by converting fw_cfg_rev_attr to 'struct kobj_attribute' where
> > this would have been caught automatically by the incompatible pointer
> > types compiler warning. Update fw_cfg_showrev() accordingly.
> >
> > Fixes: 75f3e8e47f38 ("firmware: introduce sysfs driver for QEMU's fw_cfg device")
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1299
> > Signed-off-by: Nathan Chancellor <[email protected]>
> > ---
> > drivers/firmware/qemu_fw_cfg.c | 8 +++-----
> > 1 file changed, 3 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> > index 0078260fbabe..172c751a4f6c 100644
> > --- a/drivers/firmware/qemu_fw_cfg.c
> > +++ b/drivers/firmware/qemu_fw_cfg.c
> > @@ -299,15 +299,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
> > return 0;
> > }
> >
> > -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
> > +static ssize_t fw_cfg_showrev(struct kobject *k, struct kobj_attribute *a,
> > + char *buf)
> > {
> > return sprintf(buf, "%u\n", fw_cfg_rev);
> > }
> >
> > -static const struct {
> > - struct attribute attr;
> > - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
> > -} fw_cfg_rev_attr = {
> > +static const struct kobj_attribute fw_cfg_rev_attr = {
> > .attr = { .name = "rev", .mode = S_IRUSR },
> > .show = fw_cfg_showrev,
> > };
> >
> > base-commit: 92bf22614b21a2706f4993b278017e437f7785b3
> > --
> > 2.30.1
> >
On Thu, Feb 11, 2021 at 9:41 PM 'Sami Tolvanen' via Clang Built Linux
<[email protected]> wrote:
>
> Hi Nathan,
>
> On Thu, Feb 11, 2021 at 11:43 AM Nathan Chancellor <[email protected]> wrote:
> >
> > fw_cfg_showrev() is called by an indirect call in kobj_attr_show(),
> > which violates clang's CFI checking because fw_cfg_showrev()'s second
> > parameter is 'struct attribute', whereas the ->show() member of 'struct
> > kobj_structure' expects the second parameter to be of type 'struct
> > kobj_attribute'.
> >
> > $ cat /sys/firmware/qemu_fw_cfg/rev
> > 3
> >
> > $ dmesg | grep "CFI failure"
> > [ 26.016832] CFI failure (target: fw_cfg_showrev+0x0/0x8):
> >
> > Fix this by converting fw_cfg_rev_attr to 'struct kobj_attribute' where
> > this would have been caught automatically by the incompatible pointer
> > types compiler warning. Update fw_cfg_showrev() accordingly.
> >
> > Fixes: 75f3e8e47f38 ("firmware: introduce sysfs driver for QEMU's fw_cfg device")
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1299
> > Signed-off-by: Nathan Chancellor <[email protected]>
>
> Looks good to me. Thank you for sending the patch!
>
> Reviewed-by: Sami Tolvanen <[email protected]>
>
Environment: Linux v5.11-10201-gc03c21ba6f4e plus Clang-CFI as of
24-Feb-2021 on top built with LLVM v13-git.
Tested-by: Sedat Dilek <[email protected]>
- Sedat -
On Thu, Feb 11, 2021 at 12:42:58PM -0700, Nathan Chancellor wrote:
> fw_cfg_showrev() is called by an indirect call in kobj_attr_show(),
> which violates clang's CFI checking because fw_cfg_showrev()'s second
> parameter is 'struct attribute', whereas the ->show() member of 'struct
> kobj_structure' expects the second parameter to be of type 'struct
> kobj_attribute'.
>
> $ cat /sys/firmware/qemu_fw_cfg/rev
> 3
>
> $ dmesg | grep "CFI failure"
> [ 26.016832] CFI failure (target: fw_cfg_showrev+0x0/0x8):
>
> Fix this by converting fw_cfg_rev_attr to 'struct kobj_attribute' where
> this would have been caught automatically by the incompatible pointer
> types compiler warning. Update fw_cfg_showrev() accordingly.
>
> Fixes: 75f3e8e47f38 ("firmware: introduce sysfs driver for QEMU's fw_cfg device")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1299
> Signed-off-by: Nathan Chancellor <[email protected]>
Ah, nice, yes.
Reviewed-by: Kees Cook <[email protected]>
Michael, are you able to take this? I can snag it if needed.
-Kees
> ---
> drivers/firmware/qemu_fw_cfg.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> index 0078260fbabe..172c751a4f6c 100644
> --- a/drivers/firmware/qemu_fw_cfg.c
> +++ b/drivers/firmware/qemu_fw_cfg.c
> @@ -299,15 +299,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
> return 0;
> }
>
> -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
> +static ssize_t fw_cfg_showrev(struct kobject *k, struct kobj_attribute *a,
> + char *buf)
> {
> return sprintf(buf, "%u\n", fw_cfg_rev);
> }
>
> -static const struct {
> - struct attribute attr;
> - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
> -} fw_cfg_rev_attr = {
> +static const struct kobj_attribute fw_cfg_rev_attr = {
> .attr = { .name = "rev", .mode = S_IRUSR },
> .show = fw_cfg_showrev,
> };
>
> base-commit: 92bf22614b21a2706f4993b278017e437f7785b3
> --
> 2.30.1
>
--
Kees Cook
On 2/11/21 8:42 PM, Nathan Chancellor wrote:
> fw_cfg_showrev() is called by an indirect call in kobj_attr_show(),
> which violates clang's CFI checking because fw_cfg_showrev()'s second
> parameter is 'struct attribute', whereas the ->show() member of 'struct
> kobj_structure' expects the second parameter to be of type 'struct
> kobj_attribute'.
>
> $ cat /sys/firmware/qemu_fw_cfg/rev
> 3
>
> $ dmesg | grep "CFI failure"
> [ 26.016832] CFI failure (target: fw_cfg_showrev+0x0/0x8):
>
> Fix this by converting fw_cfg_rev_attr to 'struct kobj_attribute' where
> this would have been caught automatically by the incompatible pointer
> types compiler warning. Update fw_cfg_showrev() accordingly.
>
> Fixes: 75f3e8e47f38 ("firmware: introduce sysfs driver for QEMU's fw_cfg device")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1299
> Signed-off-by: Nathan Chancellor <[email protected]>
> ---
> drivers/firmware/qemu_fw_cfg.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
On Thu, 11 Feb 2021 12:42:58 -0700, Nathan Chancellor wrote:
> fw_cfg_showrev() is called by an indirect call in kobj_attr_show(),
> which violates clang's CFI checking because fw_cfg_showrev()'s second
> parameter is 'struct attribute', whereas the ->show() member of 'struct
> kobj_structure' expects the second parameter to be of type 'struct
> kobj_attribute'.
>
> $ cat /sys/firmware/qemu_fw_cfg/rev
> 3
>
> [...]
Applied to kspp/cfi/cleanups, thanks!
[1/1] qemu_fw_cfg: Make fw_cfg_rev_attr a proper kobj_attribute
https://git.kernel.org/kees/c/f5c4679d6c49
--
Kees Cook
On Thu, Feb 25, 2021 at 10:25 PM Kees Cook <[email protected]> wrote:
>
> On Thu, 11 Feb 2021 12:42:58 -0700, Nathan Chancellor wrote:
> > fw_cfg_showrev() is called by an indirect call in kobj_attr_show(),
> > which violates clang's CFI checking because fw_cfg_showrev()'s second
> > parameter is 'struct attribute', whereas the ->show() member of 'struct
> > kobj_structure' expects the second parameter to be of type 'struct
> > kobj_attribute'.
> >
> > $ cat /sys/firmware/qemu_fw_cfg/rev
> > 3
> >
> > [...]
>
> Applied to kspp/cfi/cleanups, thanks!
>
> [1/1] qemu_fw_cfg: Make fw_cfg_rev_attr a proper kobj_attribute
> https://git.kernel.org/kees/c/f5c4679d6c49
>
I have queued this up in my custom patchset
(for-5.12/kspp-cfi-cleanups-20210225).
What is the plan to get this upstream?
Feel free to add my:
Tested-by: Sedat Dilek <[email protected]>
- Sedat -
On Fri, Apr 02, 2021 at 08:42:07AM +0200, Sedat Dilek wrote:
> On Thu, Feb 25, 2021 at 10:25 PM Kees Cook <[email protected]> wrote:
> >
> > On Thu, 11 Feb 2021 12:42:58 -0700, Nathan Chancellor wrote:
> > > fw_cfg_showrev() is called by an indirect call in kobj_attr_show(),
> > > which violates clang's CFI checking because fw_cfg_showrev()'s second
> > > parameter is 'struct attribute', whereas the ->show() member of 'struct
> > > kobj_structure' expects the second parameter to be of type 'struct
> > > kobj_attribute'.
> > >
> > > $ cat /sys/firmware/qemu_fw_cfg/rev
> > > 3
> > >
> > > [...]
> >
> > Applied to kspp/cfi/cleanups, thanks!
> >
> > [1/1] qemu_fw_cfg: Make fw_cfg_rev_attr a proper kobj_attribute
> > https://git.kernel.org/kees/c/f5c4679d6c49
> >
>
> I have queued this up in my custom patchset
> (for-5.12/kspp-cfi-cleanups-20210225).
>
> What is the plan to get this upstream?
I haven't sent it to Linus yet -- I was expecting to batch more of these
and send them for v5.13. (But if the kvm folks snag it, that's good
too.)
-Kees
>
> Feel free to add my:
>
> Tested-by: Sedat Dilek <[email protected]>
>
> - Sedat -
--
Kees Cook
On Fri, Apr 02, 2021 at 11:25:42AM -0700, Kees Cook wrote:
> On Fri, Apr 02, 2021 at 08:42:07AM +0200, Sedat Dilek wrote:
> > On Thu, Feb 25, 2021 at 10:25 PM Kees Cook <[email protected]> wrote:
> > >
> > > On Thu, 11 Feb 2021 12:42:58 -0700, Nathan Chancellor wrote:
> > > > fw_cfg_showrev() is called by an indirect call in kobj_attr_show(),
> > > > which violates clang's CFI checking because fw_cfg_showrev()'s second
> > > > parameter is 'struct attribute', whereas the ->show() member of 'struct
> > > > kobj_structure' expects the second parameter to be of type 'struct
> > > > kobj_attribute'.
> > > >
> > > > $ cat /sys/firmware/qemu_fw_cfg/rev
> > > > 3
> > > >
> > > > [...]
> > >
> > > Applied to kspp/cfi/cleanups, thanks!
> > >
> > > [1/1] qemu_fw_cfg: Make fw_cfg_rev_attr a proper kobj_attribute
> > > https://git.kernel.org/kees/c/f5c4679d6c49
> > >
> >
> > I have queued this up in my custom patchset
> > (for-5.12/kspp-cfi-cleanups-20210225).
> >
> > What is the plan to get this upstream?
>
> I haven't sent it to Linus yet -- I was expecting to batch more of these
> and send them for v5.13. (But if the kvm folks snag it, that's good
> too.)
I am going to be putting the CFI series through its paces on both arm64
and x86_64 over the next week or so on several different machines (in
fact, I am writing up a report right now) so I will probably have some
more of these as I find them.
Cheers,
Nathan
On Fri, Apr 2, 2021 at 8:31 PM Nathan Chancellor <[email protected]> wrote:
>
> On Fri, Apr 02, 2021 at 11:25:42AM -0700, Kees Cook wrote:
> > On Fri, Apr 02, 2021 at 08:42:07AM +0200, Sedat Dilek wrote:
> > > On Thu, Feb 25, 2021 at 10:25 PM Kees Cook <[email protected]> wrote:
> > > >
> > > > On Thu, 11 Feb 2021 12:42:58 -0700, Nathan Chancellor wrote:
> > > > > fw_cfg_showrev() is called by an indirect call in kobj_attr_show(),
> > > > > which violates clang's CFI checking because fw_cfg_showrev()'s second
> > > > > parameter is 'struct attribute', whereas the ->show() member of 'struct
> > > > > kobj_structure' expects the second parameter to be of type 'struct
> > > > > kobj_attribute'.
> > > > >
> > > > > $ cat /sys/firmware/qemu_fw_cfg/rev
> > > > > 3
> > > > >
> > > > > [...]
> > > >
> > > > Applied to kspp/cfi/cleanups, thanks!
> > > >
> > > > [1/1] qemu_fw_cfg: Make fw_cfg_rev_attr a proper kobj_attribute
> > > > https://git.kernel.org/kees/c/f5c4679d6c49
> > > >
> > >
> > > I have queued this up in my custom patchset
> > > (for-5.12/kspp-cfi-cleanups-20210225).
> > >
> > > What is the plan to get this upstream?
> >
> > I haven't sent it to Linus yet -- I was expecting to batch more of these
> > and send them for v5.13. (But if the kvm folks snag it, that's good
> > too.)
>
> I am going to be putting the CFI series through its paces on both arm64
> and x86_64 over the next week or so on several different machines (in
> fact, I am writing up a report right now) so I will probably have some
> more of these as I find them.
>
This was just a friendly ping.
Sami has sent some patches which I reported in the early stage of
clang-cfi (x86-64) through subtree maintainers.
It's up to you Nathan or kvm folks.
Upstreamed patches means to me a RDC-ed custom patchset.
- Sedat -