Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).
While there, use struct_size() helper, instead of the open-coded
version, to calculate the size for the allocation of the whole
flexible structure, including of course, the flexible-array member.
This code was found with the help of Coccinelle, and audited and
fixed manually.
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
drivers/net/wireless/intersil/hostap/hostap_download.c | 3 +--
drivers/net/wireless/intersil/hostap/hostap_wlan.h | 2 +-
2 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/net/wireless/intersil/hostap/hostap_download.c b/drivers/net/wireless/intersil/hostap/hostap_download.c
index 3672291ced5c..5e5bada28b5b 100644
--- a/drivers/net/wireless/intersil/hostap/hostap_download.c
+++ b/drivers/net/wireless/intersil/hostap/hostap_download.c
@@ -732,8 +732,7 @@ static int prism2_download(local_info_t *local,
goto out;
}
- dl = kzalloc(sizeof(*dl) + param->num_areas *
- sizeof(struct prism2_download_data_area), GFP_KERNEL);
+ dl = kzalloc(struct_size(dl, data, param->num_areas), GFP_KERNEL);
if (dl == NULL) {
ret = -ENOMEM;
goto out;
diff --git a/drivers/net/wireless/intersil/hostap/hostap_wlan.h b/drivers/net/wireless/intersil/hostap/hostap_wlan.h
index c25cd21d18bd..f71c0545c0be 100644
--- a/drivers/net/wireless/intersil/hostap/hostap_wlan.h
+++ b/drivers/net/wireless/intersil/hostap/hostap_wlan.h
@@ -617,7 +617,7 @@ struct prism2_download_data {
u32 addr; /* wlan card address */
u32 len;
u8 *data; /* allocated data */
- } data[];
+ } data[] __counted_by(num_areas);
};
--
2.34.1
On 10/9/23 21:54, Kees Cook wrote:
> On Mon, Oct 09, 2023 at 01:41:18PM -0600, Gustavo A. R. Silva wrote:
>> Prepare for the coming implementation by GCC and Clang of the __counted_by
>> attribute. Flexible array members annotated with __counted_by can have
>> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
>> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
>> functions).
>>
>> While there, use struct_size() helper, instead of the open-coded
>> version, to calculate the size for the allocation of the whole
>> flexible structure, including of course, the flexible-array member.
>>
>> This code was found with the help of Coccinelle, and audited and
>> fixed manually.
>>
>> Signed-off-by: Gustavo A. R. Silva <[email protected]>
>> ---
>> drivers/net/wireless/intersil/hostap/hostap_download.c | 3 +--
>> drivers/net/wireless/intersil/hostap/hostap_wlan.h | 2 +-
>> 2 files changed, 2 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/net/wireless/intersil/hostap/hostap_download.c b/drivers/net/wireless/intersil/hostap/hostap_download.c
>> index 3672291ced5c..5e5bada28b5b 100644
>> --- a/drivers/net/wireless/intersil/hostap/hostap_download.c
>> +++ b/drivers/net/wireless/intersil/hostap/hostap_download.c
>> @@ -732,8 +732,7 @@ static int prism2_download(local_info_t *local,
>> goto out;
>> }
>>
>> - dl = kzalloc(sizeof(*dl) + param->num_areas *
>> - sizeof(struct prism2_download_data_area), GFP_KERNEL);
>> + dl = kzalloc(struct_size(dl, data, param->num_areas), GFP_KERNEL);
>> if (dl == NULL) {
>> ret = -ENOMEM;
>> goto out;
>> diff --git a/drivers/net/wireless/intersil/hostap/hostap_wlan.h b/drivers/net/wireless/intersil/hostap/hostap_wlan.h
>> index c25cd21d18bd..f71c0545c0be 100644
>> --- a/drivers/net/wireless/intersil/hostap/hostap_wlan.h
>> +++ b/drivers/net/wireless/intersil/hostap/hostap_wlan.h
>> @@ -617,7 +617,7 @@ struct prism2_download_data {
>> u32 addr; /* wlan card address */
>> u32 len;
>> u8 *data; /* allocated data */
>> - } data[];
>> + } data[] __counted_by(num_areas);
>> };
>
> Should this be considered a v2 of:
> https://lore.kernel.org/linux-hardening/[email protected]/
>
> ?
Oops... sorry, I forgot I had reviewed this patch of yours.
>
> Yours is more complete since it includes the struct_size() change...
>
Should I resend this explicitly marking it as a v2?
--
Gustavo
On Mon, Oct 09, 2023 at 02:33:01PM -0600, Gustavo A. R. Silva wrote:
>
>
> On 10/9/23 21:54, Kees Cook wrote:
> > On Mon, Oct 09, 2023 at 01:41:18PM -0600, Gustavo A. R. Silva wrote:
> > > Prepare for the coming implementation by GCC and Clang of the __counted_by
> > > attribute. Flexible array members annotated with __counted_by can have
> > > their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> > > array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> > > functions).
> > >
> > > While there, use struct_size() helper, instead of the open-coded
> > > version, to calculate the size for the allocation of the whole
> > > flexible structure, including of course, the flexible-array member.
> > >
> > > This code was found with the help of Coccinelle, and audited and
> > > fixed manually.
> > >
> > > Signed-off-by: Gustavo A. R. Silva <[email protected]>
> > > ---
> > > drivers/net/wireless/intersil/hostap/hostap_download.c | 3 +--
> > > drivers/net/wireless/intersil/hostap/hostap_wlan.h | 2 +-
> > > 2 files changed, 2 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/net/wireless/intersil/hostap/hostap_download.c b/drivers/net/wireless/intersil/hostap/hostap_download.c
> > > index 3672291ced5c..5e5bada28b5b 100644
> > > --- a/drivers/net/wireless/intersil/hostap/hostap_download.c
> > > +++ b/drivers/net/wireless/intersil/hostap/hostap_download.c
> > > @@ -732,8 +732,7 @@ static int prism2_download(local_info_t *local,
> > > goto out;
> > > }
> > > - dl = kzalloc(sizeof(*dl) + param->num_areas *
> > > - sizeof(struct prism2_download_data_area), GFP_KERNEL);
> > > + dl = kzalloc(struct_size(dl, data, param->num_areas), GFP_KERNEL);
> > > if (dl == NULL) {
> > > ret = -ENOMEM;
> > > goto out;
> > > diff --git a/drivers/net/wireless/intersil/hostap/hostap_wlan.h b/drivers/net/wireless/intersil/hostap/hostap_wlan.h
> > > index c25cd21d18bd..f71c0545c0be 100644
> > > --- a/drivers/net/wireless/intersil/hostap/hostap_wlan.h
> > > +++ b/drivers/net/wireless/intersil/hostap/hostap_wlan.h
> > > @@ -617,7 +617,7 @@ struct prism2_download_data {
> > > u32 addr; /* wlan card address */
> > > u32 len;
> > > u8 *data; /* allocated data */
> > > - } data[];
> > > + } data[] __counted_by(num_areas);
> > > };
> >
> > Should this be considered a v2 of:
> > https://lore.kernel.org/linux-hardening/[email protected]/
> >
> > ?
>
> Oops... sorry, I forgot I had reviewed this patch of yours.
>
> >
> > Yours is more complete since it includes the struct_size() change...
> >
>
> Should I resend this explicitly marking it as a v2?
I defer to Kalle -- your Subject is more accurate, so perhaps let's just
let this stand?
--
Kees Cook
Kees Cook <[email protected]> writes:
>> > Should this be considered a v2 of:
>> > https://lore.kernel.org/linux-hardening/[email protected]/
>> >
>> > ?
>>
>> Oops... sorry, I forgot I had reviewed this patch of yours.
>>
>> >
>> > Yours is more complete since it includes the struct_size() change...
>> >
>>
>> Should I resend this explicitly marking it as a v2?
>
> I defer to Kalle -- your Subject is more accurate, so perhaps let's just
> let this stand?
No need to resend. I marked Kees' version as Superseded so that I don't
accidentally take the wrong version.
In the title "wifi:" is missing but I can add that during commit.
--
https://patchwork.kernel.org/project/linux-wireless/list/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
On 10/10/23 08:17, Kalle Valo wrote:
>
> No need to resend. I marked Kees' version as Superseded so that I don't
> accidentally take the wrong version.
>
> In the title "wifi:" is missing but I can add that during commit.
>
Awesome. :)
Thanks, Kalle!
--
Gustavo
On Mon, Oct 09, 2023 at 01:41:18PM -0600, Gustavo A. R. Silva wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
>
> While there, use struct_size() helper, instead of the open-coded
> version, to calculate the size for the allocation of the whole
> flexible structure, including of course, the flexible-array member.
>
> This code was found with the help of Coccinelle, and audited and
> fixed manually.
>
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
I realize I didn't actually send my R-b for this thread, so here it is:
Reviewed-by: Kees Cook <[email protected]>
:)
--
Kees Cook
> I realize I didn't actually send my R-b for this thread, so here it is:
>
> Reviewed-by: Kees Cook <[email protected]>
>
> :)
>
Thanks! :)
--
Gustavo
"Gustavo A. R. Silva" <[email protected]> wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
>
> While there, use struct_size() helper, instead of the open-coded
> version, to calculate the size for the allocation of the whole
> flexible structure, including of course, the flexible-array member.
>
> This code was found with the help of Coccinelle, and audited and
> fixed manually.
>
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
> Reviewed-by: Kees Cook <[email protected]>
Patch applied to wireless-next.git, thanks.
5cf47dc14158 wifi: hostap: Add __counted_by for struct prism2_download_data and use struct_size()
--
https://patchwork.kernel.org/project/linux-wireless/patch/ZSRXXvWMMkm7qqRW@work/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches