2021-10-15 12:09:06

by Gustavo A. R. Silva

[permalink] [raw]
Subject: [PATCH][next] powerpc/vas: Fix potential NULL pointer dereference

(!ptr && !ptr->foo) strikes again. :)

The expression (!ptr && !ptr->foo) is bogus and in case ptr is NULL,
it leads to a NULL pointer dereference: ptr->foo.

Fix this by converting && to ||

This issue was detected with the help of Coccinelle, and audited and
fixed manually.

Fixes: 1a0d0d5ed5e3 ("powerpc/vas: Add platform specific user window operations")
Cc: [email protected]
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
arch/powerpc/platforms/book3s/vas-api.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/book3s/vas-api.c b/arch/powerpc/platforms/book3s/vas-api.c
index 30172e52e16b..4d82c92ddd52 100644
--- a/arch/powerpc/platforms/book3s/vas-api.c
+++ b/arch/powerpc/platforms/book3s/vas-api.c
@@ -303,7 +303,7 @@ static int coproc_ioc_tx_win_open(struct file *fp, unsigned long arg)
return -EINVAL;
}

- if (!cp_inst->coproc->vops && !cp_inst->coproc->vops->open_win) {
+ if (!cp_inst->coproc->vops || !cp_inst->coproc->vops->open_win) {
pr_err("VAS API is not registered\n");
return -EACCES;
}
@@ -373,7 +373,7 @@ static int coproc_mmap(struct file *fp, struct vm_area_struct *vma)
return -EINVAL;
}

- if (!cp_inst->coproc->vops && !cp_inst->coproc->vops->paste_addr) {
+ if (!cp_inst->coproc->vops || !cp_inst->coproc->vops->paste_addr) {
pr_err("%s(): VAS API is not registered\n", __func__);
return -EACCES;
}
--
2.27.0


2021-10-18 21:12:10

by Tyrel Datwyler

[permalink] [raw]
Subject: Re: [PATCH][next] powerpc/vas: Fix potential NULL pointer dereference

On 10/14/21 10:03 PM, Gustavo A. R. Silva wrote:
> (!ptr && !ptr->foo) strikes again. :)
>
> The expression (!ptr && !ptr->foo) is bogus and in case ptr is NULL,
> it leads to a NULL pointer dereference: ptr->foo.
>
> Fix this by converting && to ||
>
> This issue was detected with the help of Coccinelle, and audited and
> fixed manually.
>
> Fixes: 1a0d0d5ed5e3 ("powerpc/vas: Add platform specific user window operations")
> Cc: [email protected]
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
Looking at the usage pattern it is obvious that if we determine !ptr attempting
to also confirm !ptr->ops is going to blow up.

LGTM.

Reviewed-by: Tyrel Datwyler <[email protected]>

> ---
> arch/powerpc/platforms/book3s/vas-api.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/platforms/book3s/vas-api.c b/arch/powerpc/platforms/book3s/vas-api.c
> index 30172e52e16b..4d82c92ddd52 100644
> --- a/arch/powerpc/platforms/book3s/vas-api.c
> +++ b/arch/powerpc/platforms/book3s/vas-api.c
> @@ -303,7 +303,7 @@ static int coproc_ioc_tx_win_open(struct file *fp, unsigned long arg)
> return -EINVAL;
> }
>
> - if (!cp_inst->coproc->vops && !cp_inst->coproc->vops->open_win) {
> + if (!cp_inst->coproc->vops || !cp_inst->coproc->vops->open_win) {
> pr_err("VAS API is not registered\n");
> return -EACCES;
> }
> @@ -373,7 +373,7 @@ static int coproc_mmap(struct file *fp, struct vm_area_struct *vma)
> return -EINVAL;
> }
>
> - if (!cp_inst->coproc->vops && !cp_inst->coproc->vops->paste_addr) {
> + if (!cp_inst->coproc->vops || !cp_inst->coproc->vops->paste_addr) {
> pr_err("%s(): VAS API is not registered\n", __func__);
> return -EACCES;
> }
>

2021-10-18 21:23:56

by Gustavo A. R. Silva

[permalink] [raw]
Subject: Re: [PATCH][next] powerpc/vas: Fix potential NULL pointer dereference

On Mon, Oct 18, 2021 at 02:09:31PM -0700, Tyrel Datwyler wrote:
> On 10/14/21 10:03 PM, Gustavo A. R. Silva wrote:
> > (!ptr && !ptr->foo) strikes again. :)
> >
> > The expression (!ptr && !ptr->foo) is bogus and in case ptr is NULL,
> > it leads to a NULL pointer dereference: ptr->foo.
> >
> > Fix this by converting && to ||
> >
> > This issue was detected with the help of Coccinelle, and audited and
> > fixed manually.
> >
> > Fixes: 1a0d0d5ed5e3 ("powerpc/vas: Add platform specific user window operations")
> > Cc: [email protected]
> > Signed-off-by: Gustavo A. R. Silva <[email protected]>
> Looking at the usage pattern it is obvious that if we determine !ptr attempting
> to also confirm !ptr->ops is going to blow up.
>
> LGTM.
>
> Reviewed-by: Tyrel Datwyler <[email protected]>

Thanks, Tyrel.
--
Gustavo

>
> > ---
> > arch/powerpc/platforms/book3s/vas-api.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/powerpc/platforms/book3s/vas-api.c b/arch/powerpc/platforms/book3s/vas-api.c
> > index 30172e52e16b..4d82c92ddd52 100644
> > --- a/arch/powerpc/platforms/book3s/vas-api.c
> > +++ b/arch/powerpc/platforms/book3s/vas-api.c
> > @@ -303,7 +303,7 @@ static int coproc_ioc_tx_win_open(struct file *fp, unsigned long arg)
> > return -EINVAL;
> > }
> >
> > - if (!cp_inst->coproc->vops && !cp_inst->coproc->vops->open_win) {
> > + if (!cp_inst->coproc->vops || !cp_inst->coproc->vops->open_win) {
> > pr_err("VAS API is not registered\n");
> > return -EACCES;
> > }
> > @@ -373,7 +373,7 @@ static int coproc_mmap(struct file *fp, struct vm_area_struct *vma)
> > return -EINVAL;
> > }
> >
> > - if (!cp_inst->coproc->vops && !cp_inst->coproc->vops->paste_addr) {
> > + if (!cp_inst->coproc->vops || !cp_inst->coproc->vops->paste_addr) {
> > pr_err("%s(): VAS API is not registered\n", __func__);
> > return -EACCES;
> > }
> >
>

2021-10-27 07:08:11

by Gustavo A. R. Silva

[permalink] [raw]
Subject: Re: [PATCH][next] powerpc/vas: Fix potential NULL pointer dereference

On Mon, Oct 18, 2021 at 02:09:31PM -0700, Tyrel Datwyler wrote:
> On 10/14/21 10:03 PM, Gustavo A. R. Silva wrote:
> > (!ptr && !ptr->foo) strikes again. :)
> >
> > The expression (!ptr && !ptr->foo) is bogus and in case ptr is NULL,
> > it leads to a NULL pointer dereference: ptr->foo.
> >
> > Fix this by converting && to ||
> >
> > This issue was detected with the help of Coccinelle, and audited and
> > fixed manually.
> >
> > Fixes: 1a0d0d5ed5e3 ("powerpc/vas: Add platform specific user window operations")
> > Cc: [email protected]
> > Signed-off-by: Gustavo A. R. Silva <[email protected]>
> Looking at the usage pattern it is obvious that if we determine !ptr attempting
> to also confirm !ptr->ops is going to blow up.
>
> LGTM.
>
> Reviewed-by: Tyrel Datwyler <[email protected]>

I think I'll take this in my tree.

Thanks, Tyrel.
--
Gustavo

2021-10-27 12:31:04

by Gustavo A. R. Silva

[permalink] [raw]
Subject: Re: [PATCH][next] powerpc/vas: Fix potential NULL pointer dereference

On Wed, Oct 27, 2021 at 09:30:53AM +1100, Michael Ellerman wrote:
[..]
> > I think I'll take this in my tree.
>
> I've already put it in powerpc/next:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=next&id=61cb9ac66b30374c7fd8a8b2a3c4f8f432c72e36

Oh, great. :)

> If you need to pick it up as well for some reason that's fine.

I just didn't want it to get lost somehow. I'll drop it from tree now.

Thanks
--
Gustavo


2021-10-27 12:31:05

by Michael Ellerman

[permalink] [raw]
Subject: Re: [PATCH][next] powerpc/vas: Fix potential NULL pointer dereference

"Gustavo A. R. Silva" <[email protected]> writes:
> On Mon, Oct 18, 2021 at 02:09:31PM -0700, Tyrel Datwyler wrote:
>> On 10/14/21 10:03 PM, Gustavo A. R. Silva wrote:
>> > (!ptr && !ptr->foo) strikes again. :)
>> >
>> > The expression (!ptr && !ptr->foo) is bogus and in case ptr is NULL,
>> > it leads to a NULL pointer dereference: ptr->foo.
>> >
>> > Fix this by converting && to ||
>> >
>> > This issue was detected with the help of Coccinelle, and audited and
>> > fixed manually.
>> >
>> > Fixes: 1a0d0d5ed5e3 ("powerpc/vas: Add platform specific user window operations")
>> > Cc: [email protected]
>> > Signed-off-by: Gustavo A. R. Silva <[email protected]>
>> Looking at the usage pattern it is obvious that if we determine !ptr attempting
>> to also confirm !ptr->ops is going to blow up.
>>
>> LGTM.
>>
>> Reviewed-by: Tyrel Datwyler <[email protected]>
>
> I think I'll take this in my tree.

I've already put it in powerpc/next:

https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=next&id=61cb9ac66b30374c7fd8a8b2a3c4f8f432c72e36

If you need to pick it up as well for some reason that's fine.

cheers

2021-10-27 21:24:21

by Michael Ellerman

[permalink] [raw]
Subject: Re: [PATCH][next] powerpc/vas: Fix potential NULL pointer dereference

"Gustavo A. R. Silva" <[email protected]> writes:
> On Wed, Oct 27, 2021 at 09:30:53AM +1100, Michael Ellerman wrote:
> [..]
>> > I think I'll take this in my tree.
>>
>> I've already put it in powerpc/next:
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=next&id=61cb9ac66b30374c7fd8a8b2a3c4f8f432c72e36
>
> Oh, great. :)
>
>> If you need to pick it up as well for some reason that's fine.
>
> I just didn't want it to get lost somehow. I'll drop it from tree now.

No worries, sorry I've been so slow lately.

cheers

2021-11-02 11:42:53

by Michael Ellerman

[permalink] [raw]
Subject: Re: [PATCH][next] powerpc/vas: Fix potential NULL pointer dereference

On Fri, 15 Oct 2021 00:03:45 -0500, Gustavo A. R. Silva wrote:
> (!ptr && !ptr->foo) strikes again. :)
>
> The expression (!ptr && !ptr->foo) is bogus and in case ptr is NULL,
> it leads to a NULL pointer dereference: ptr->foo.
>
> Fix this by converting && to ||
>
> [...]

Applied to powerpc/next.

[1/1] powerpc/vas: Fix potential NULL pointer dereference
https://git.kernel.org/powerpc/c/61cb9ac66b30374c7fd8a8b2a3c4f8f432c72e36

cheers