[PATCH] wifi: iwlegacy: Fix "field-spanning write" warning in il_enqueue_hcmd()

[PATCH] wifi: iwlegacy: Fix "field-spanning write" warning in il_enqueue_hcmd()

[Ben Hutchings]

[-- Attachment #1: Type: text/plain, Size: 3651 bytes --]

iwlegacy uses command buffers with a payload size of 320
bytes (default) or 4092 bytes (huge).  The struct il_device_cmd type
describes the default buffers and there is no separate type describing
the huge buffers.

The il_enqueue_hcmd() function works with both default and huge
buffers, and has a memcpy() to the buffer payload.  The size of
this copy may exceed 320 bytes when using a huge buffer, which
now results in a run-time warning:

    memcpy: detected field-spanning write (size 1014) of single field "&out_cmd->cmd.payload" at drivers/net/wireless/intel/iwlegacy/common.c:3170 (size 320)

To fix this:

- Define a new struct type for huge buffers, with a correctly sized
  payload field
- When using a huge buffer in il_enqueue_hcmd(), cast the command
  buffer pointer to that type when looking up the payload field

Reported-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
References: https://bugs.debian.org/1062421
References: https://bugzilla.kernel.org/show_bug.cgi?id=219124
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Fixes: 54d9469bc515 ("fortify: Add run-time WARN for cross-field memcpy()")
Tested-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
Tested-by: Brandon Nielsen <nielsenb@jetfuse.net>
---
 drivers/net/wireless/intel/iwlegacy/common.c | 13 ++++++++++++-
 drivers/net/wireless/intel/iwlegacy/common.h | 12 ++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/intel/iwlegacy/common.c b/drivers/net/wireless/intel/iwlegacy/common.c
index 9d33a66a49b5..4616293ec0cf 100644
--- a/drivers/net/wireless/intel/iwlegacy/common.c
+++ b/drivers/net/wireless/intel/iwlegacy/common.c
@@ -3122,6 +3122,7 @@ il_enqueue_hcmd(struct il_priv *il, struct il_host_cmd *cmd)
 	struct il_cmd_meta *out_meta;
 	dma_addr_t phys_addr;
 	unsigned long flags;
+	u8 *out_payload;
 	u32 idx;
 	u16 fix_size;
 
@@ -3157,6 +3158,16 @@ il_enqueue_hcmd(struct il_priv *il, struct il_host_cmd *cmd)
 	out_cmd = txq->cmd[idx];
 	out_meta = &txq->meta[idx];
 
+	/* The payload is in the same place in regular and huge
+	 * command buffers, but we need to let the compiler know when
+	 * we're using a larger payload buffer to avoid "field-
+	 * spanning write" warnings at run-time for huge commands.
+	 */
+	if (cmd->flags & CMD_SIZE_HUGE)
+		out_payload = ((struct il_device_cmd_huge *)out_cmd)->cmd.payload;
+	else
+		out_payload = out_cmd->cmd.payload;
+
 	if (WARN_ON(out_meta->flags & CMD_MAPPED)) {
 		spin_unlock_irqrestore(&il->hcmd_lock, flags);
 		return -ENOSPC;
@@ -3170,7 +3181,7 @@ il_enqueue_hcmd(struct il_priv *il, struct il_host_cmd *cmd)
 		out_meta->callback = cmd->callback;
 
 	out_cmd->hdr.cmd = cmd->id;
-	memcpy(&out_cmd->cmd.payload, cmd->data, cmd->len);
+	memcpy(out_payload, cmd->data, cmd->len);
 
 	/* At this point, the out_cmd now has all of the incoming cmd
 	 * information */
diff --git a/drivers/net/wireless/intel/iwlegacy/common.h b/drivers/net/wireless/intel/iwlegacy/common.h
index 69687fcf963f..027dae5619a3 100644
--- a/drivers/net/wireless/intel/iwlegacy/common.h
+++ b/drivers/net/wireless/intel/iwlegacy/common.h
@@ -560,6 +560,18 @@ struct il_device_cmd {
 
 #define TFD_MAX_PAYLOAD_SIZE (sizeof(struct il_device_cmd))
 
+/**
+ * struct il_device_cmd_huge
+ *
+ * For use when sending huge commands.
+ */
+struct il_device_cmd_huge {
+	struct il_cmd_header hdr;	/* uCode API */
+	union {
+		u8 payload[IL_MAX_CMD_SIZE - sizeof(struct il_cmd_header)];
+	} __packed cmd;
+} __packed;
+
 struct il_host_cmd {
 	const void *data;
 	unsigned long reply_page;

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Re: [PATCH] wifi: iwlegacy: Fix "field-spanning write" warning in il_enqueue_hcmd()

[Stanislaw Gruszka]

On Thu, Sep 12, 2024 at 01:01:21AM +0200, Ben Hutchings wrote:
> iwlegacy uses command buffers with a payload size of 320
> bytes (default) or 4092 bytes (huge).  The struct il_device_cmd type
> describes the default buffers and there is no separate type describing
> the huge buffers.
> 
> The il_enqueue_hcmd() function works with both default and huge
> buffers, and has a memcpy() to the buffer payload.  The size of
> this copy may exceed 320 bytes when using a huge buffer, which
> now results in a run-time warning:
> 
>     memcpy: detected field-spanning write (size 1014) of single field "&out_cmd->cmd.payload" at drivers/net/wireless/intel/iwlegacy/common.c:3170 (size 320)
> 
> To fix this:
> 
> - Define a new struct type for huge buffers, with a correctly sized
>   payload field
> - When using a huge buffer in il_enqueue_hcmd(), cast the command
>   buffer pointer to that type when looking up the payload field
> 
> Reported-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
> References: https://bugs.debian.org/1062421
> References: https://bugzilla.kernel.org/show_bug.cgi?id=219124
> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
> Fixes: 54d9469bc515 ("fortify: Add run-time WARN for cross-field memcpy()")
> Tested-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
> Tested-by: Brandon Nielsen <nielsenb@jetfuse.net>

I proposed diffrent fix for this here:
https://lore.kernel.org/linux-wireless/20240520073210.GA693073@wp.pl/
but never get feedback if it works on real HW.
So I prefer this one, sice it was tested.

Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>

Martin-Éric and Brandon, could you plase also test patch from 
https://lore.kernel.org/linux-wireless/Zr2gxERA3RL3EwRe@elsanto/
if it does not break the driver?

Thanks
Stanislaw

> ---
>  drivers/net/wireless/intel/iwlegacy/common.c | 13 ++++++++++++-
>  drivers/net/wireless/intel/iwlegacy/common.h | 12 ++++++++++++
>  2 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/intel/iwlegacy/common.c b/drivers/net/wireless/intel/iwlegacy/common.c
> index 9d33a66a49b5..4616293ec0cf 100644
> --- a/drivers/net/wireless/intel/iwlegacy/common.c
> +++ b/drivers/net/wireless/intel/iwlegacy/common.c
> @@ -3122,6 +3122,7 @@ il_enqueue_hcmd(struct il_priv *il, struct il_host_cmd *cmd)
>  	struct il_cmd_meta *out_meta;
>  	dma_addr_t phys_addr;
>  	unsigned long flags;
> +	u8 *out_payload;
>  	u32 idx;
>  	u16 fix_size;
>  
> @@ -3157,6 +3158,16 @@ il_enqueue_hcmd(struct il_priv *il, struct il_host_cmd *cmd)
>  	out_cmd = txq->cmd[idx];
>  	out_meta = &txq->meta[idx];
>  
> +	/* The payload is in the same place in regular and huge
> +	 * command buffers, but we need to let the compiler know when
> +	 * we're using a larger payload buffer to avoid "field-
> +	 * spanning write" warnings at run-time for huge commands.
> +	 */
> +	if (cmd->flags & CMD_SIZE_HUGE)
> +		out_payload = ((struct il_device_cmd_huge *)out_cmd)->cmd.payload;
> +	else
> +		out_payload = out_cmd->cmd.payload;
> +
>  	if (WARN_ON(out_meta->flags & CMD_MAPPED)) {
>  		spin_unlock_irqrestore(&il->hcmd_lock, flags);
>  		return -ENOSPC;
> @@ -3170,7 +3181,7 @@ il_enqueue_hcmd(struct il_priv *il, struct il_host_cmd *cmd)
>  		out_meta->callback = cmd->callback;
>  
>  	out_cmd->hdr.cmd = cmd->id;
> -	memcpy(&out_cmd->cmd.payload, cmd->data, cmd->len);
> +	memcpy(out_payload, cmd->data, cmd->len);
>  
>  	/* At this point, the out_cmd now has all of the incoming cmd
>  	 * information */
> diff --git a/drivers/net/wireless/intel/iwlegacy/common.h b/drivers/net/wireless/intel/iwlegacy/common.h
> index 69687fcf963f..027dae5619a3 100644
> --- a/drivers/net/wireless/intel/iwlegacy/common.h
> +++ b/drivers/net/wireless/intel/iwlegacy/common.h
> @@ -560,6 +560,18 @@ struct il_device_cmd {
>  
>  #define TFD_MAX_PAYLOAD_SIZE (sizeof(struct il_device_cmd))
>  
> +/**
> + * struct il_device_cmd_huge
> + *
> + * For use when sending huge commands.
> + */
> +struct il_device_cmd_huge {
> +	struct il_cmd_header hdr;	/* uCode API */
> +	union {
> +		u8 payload[IL_MAX_CMD_SIZE - sizeof(struct il_cmd_header)];
> +	} __packed cmd;
> +} __packed;
> +
>  struct il_host_cmd {
>  	const void *data;
>  	unsigned long reply_page;

Re: [PATCH] wifi: iwlegacy: Fix "field-spanning write" warning in il_enqueue_hcmd()

[Brandon Nielsen]

On 9/12/24 3:39 AM, Stanislaw Gruszka wrote:
> On Thu, Sep 12, 2024 at 01:01:21AM +0200, Ben Hutchings wrote:
>> iwlegacy uses command buffers with a payload size of 320
>> bytes (default) or 4092 bytes (huge).  The struct il_device_cmd type
>> describes the default buffers and there is no separate type describing
>> the huge buffers.
>>
>> The il_enqueue_hcmd() function works with both default and huge
>> buffers, and has a memcpy() to the buffer payload.  The size of
>> this copy may exceed 320 bytes when using a huge buffer, which
>> now results in a run-time warning:
>>
>>      memcpy: detected field-spanning write (size 1014) of single field "&out_cmd->cmd.payload" at drivers/net/wireless/intel/iwlegacy/common.c:3170 (size 320)
>>
>> To fix this:
>>
>> - Define a new struct type for huge buffers, with a correctly sized
>>    payload field
>> - When using a huge buffer in il_enqueue_hcmd(), cast the command
>>    buffer pointer to that type when looking up the payload field
>>
>> Reported-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
>> References: https://bugs.debian.org/1062421
>> References: https://bugzilla.kernel.org/show_bug.cgi?id=219124
>> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
>> Fixes: 54d9469bc515 ("fortify: Add run-time WARN for cross-field memcpy()")
>> Tested-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
>> Tested-by: Brandon Nielsen <nielsenb@jetfuse.net>
> 
> I proposed diffrent fix for this here:
> https://lore.kernel.org/linux-wireless/20240520073210.GA693073@wp.pl/
> but never get feedback if it works on real HW.
> So I prefer this one, sice it was tested.
> 
> Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>
> 
> Martin-Éric and Brandon, could you plase also test patch from
> https://lore.kernel.org/linux-wireless/Zr2gxERA3RL3EwRe@elsanto/
> if it does not break the driver?
> 

As far as I can tell nothing breaks with that additional patch applied.

> Thanks
> Stanislaw
> 
>> ---
>>   drivers/net/wireless/intel/iwlegacy/common.c | 13 ++++++++++++-
>>   drivers/net/wireless/intel/iwlegacy/common.h | 12 ++++++++++++
>>   2 files changed, 24 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/wireless/intel/iwlegacy/common.c b/drivers/net/wireless/intel/iwlegacy/common.c
>> index 9d33a66a49b5..4616293ec0cf 100644
>> --- a/drivers/net/wireless/intel/iwlegacy/common.c
>> +++ b/drivers/net/wireless/intel/iwlegacy/common.c
>> @@ -3122,6 +3122,7 @@ il_enqueue_hcmd(struct il_priv *il, struct il_host_cmd *cmd)
>>   	struct il_cmd_meta *out_meta;
>>   	dma_addr_t phys_addr;
>>   	unsigned long flags;
>> +	u8 *out_payload;
>>   	u32 idx;
>>   	u16 fix_size;
>>   
>> @@ -3157,6 +3158,16 @@ il_enqueue_hcmd(struct il_priv *il, struct il_host_cmd *cmd)
>>   	out_cmd = txq->cmd[idx];
>>   	out_meta = &txq->meta[idx];
>>   
>> +	/* The payload is in the same place in regular and huge
>> +	 * command buffers, but we need to let the compiler know when
>> +	 * we're using a larger payload buffer to avoid "field-
>> +	 * spanning write" warnings at run-time for huge commands.
>> +	 */
>> +	if (cmd->flags & CMD_SIZE_HUGE)
>> +		out_payload = ((struct il_device_cmd_huge *)out_cmd)->cmd.payload;
>> +	else
>> +		out_payload = out_cmd->cmd.payload;
>> +
>>   	if (WARN_ON(out_meta->flags & CMD_MAPPED)) {
>>   		spin_unlock_irqrestore(&il->hcmd_lock, flags);
>>   		return -ENOSPC;
>> @@ -3170,7 +3181,7 @@ il_enqueue_hcmd(struct il_priv *il, struct il_host_cmd *cmd)
>>   		out_meta->callback = cmd->callback;
>>   
>>   	out_cmd->hdr.cmd = cmd->id;
>> -	memcpy(&out_cmd->cmd.payload, cmd->data, cmd->len);
>> +	memcpy(out_payload, cmd->data, cmd->len);
>>   
>>   	/* At this point, the out_cmd now has all of the incoming cmd
>>   	 * information */
>> diff --git a/drivers/net/wireless/intel/iwlegacy/common.h b/drivers/net/wireless/intel/iwlegacy/common.h
>> index 69687fcf963f..027dae5619a3 100644
>> --- a/drivers/net/wireless/intel/iwlegacy/common.h
>> +++ b/drivers/net/wireless/intel/iwlegacy/common.h
>> @@ -560,6 +560,18 @@ struct il_device_cmd {
>>   
>>   #define TFD_MAX_PAYLOAD_SIZE (sizeof(struct il_device_cmd))
>>   
>> +/**
>> + * struct il_device_cmd_huge
>> + *
>> + * For use when sending huge commands.
>> + */
>> +struct il_device_cmd_huge {
>> +	struct il_cmd_header hdr;	/* uCode API */
>> +	union {
>> +		u8 payload[IL_MAX_CMD_SIZE - sizeof(struct il_cmd_header)];
>> +	} __packed cmd;
>> +} __packed;
>> +
>>   struct il_host_cmd {
>>   	const void *data;
>>   	unsigned long reply_page;
> 
> 

Re: [PATCH] wifi: iwlegacy: Fix "field-spanning write" warning in il_enqueue_hcmd()

[Stanislaw Gruszka]

On Thu, Sep 12, 2024 at 12:30:42PM -0500, Brandon Nielsen wrote:
> On 9/12/24 3:39 AM, Stanislaw Gruszka wrote:
> > On Thu, Sep 12, 2024 at 01:01:21AM +0200, Ben Hutchings wrote:
> > > iwlegacy uses command buffers with a payload size of 320
> > > bytes (default) or 4092 bytes (huge).  The struct il_device_cmd type
> > > describes the default buffers and there is no separate type describing
> > > the huge buffers.
> > > 
> > > The il_enqueue_hcmd() function works with both default and huge
> > > buffers, and has a memcpy() to the buffer payload.  The size of
> > > this copy may exceed 320 bytes when using a huge buffer, which
> > > now results in a run-time warning:
> > > 
> > >      memcpy: detected field-spanning write (size 1014) of single field "&out_cmd->cmd.payload" at drivers/net/wireless/intel/iwlegacy/common.c:3170 (size 320)
> > > 
> > > To fix this:
> > > 
> > > - Define a new struct type for huge buffers, with a correctly sized
> > >    payload field
> > > - When using a huge buffer in il_enqueue_hcmd(), cast the command
> > >    buffer pointer to that type when looking up the payload field
> > > 
> > > Reported-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
> > > References: https://bugs.debian.org/1062421
> > > References: https://bugzilla.kernel.org/show_bug.cgi?id=219124
> > > Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
> > > Fixes: 54d9469bc515 ("fortify: Add run-time WARN for cross-field memcpy()")
> > > Tested-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
> > > Tested-by: Brandon Nielsen <nielsenb@jetfuse.net>
> > 
> > I proposed diffrent fix for this here:
> > https://lore.kernel.org/linux-wireless/20240520073210.GA693073@wp.pl/
> > but never get feedback if it works on real HW.
> > So I prefer this one, sice it was tested.
> > 
> > Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>
> > 
> > Martin-Éric and Brandon, could you plase also test patch from
> > https://lore.kernel.org/linux-wireless/Zr2gxERA3RL3EwRe@elsanto/
> > if it does not break the driver?
> > 
> 
> As far as I can tell nothing breaks with that additional patch applied.

Great, thanks for testing the patch. 
Stanislaw

Re: [PATCH] wifi: iwlegacy: Fix "field-spanning write" warning in il_enqueue_hcmd()

[Martin-Éric Racine]

to 12. syysk. 2024 klo 11.40 Stanislaw Gruszka (stf_xl@wp.pl) kirjoitti:
>
> On Thu, Sep 12, 2024 at 01:01:21AM +0200, Ben Hutchings wrote:
> > iwlegacy uses command buffers with a payload size of 320
> > bytes (default) or 4092 bytes (huge).  The struct il_device_cmd type
> > describes the default buffers and there is no separate type describing
> > the huge buffers.
> >
> > The il_enqueue_hcmd() function works with both default and huge
> > buffers, and has a memcpy() to the buffer payload.  The size of
> > this copy may exceed 320 bytes when using a huge buffer, which
> > now results in a run-time warning:
> >
> >     memcpy: detected field-spanning write (size 1014) of single field "&out_cmd->cmd.payload" at drivers/net/wireless/intel/iwlegacy/common.c:3170 (size 320)
> >
> > To fix this:
> >
> > - Define a new struct type for huge buffers, with a correctly sized
> >   payload field
> > - When using a huge buffer in il_enqueue_hcmd(), cast the command
> >   buffer pointer to that type when looking up the payload field
> >
> > Reported-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
> > References: https://bugs.debian.org/1062421
> > References: https://bugzilla.kernel.org/show_bug.cgi?id=219124
> > Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
> > Fixes: 54d9469bc515 ("fortify: Add run-time WARN for cross-field memcpy()")
> > Tested-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
> > Tested-by: Brandon Nielsen <nielsenb@jetfuse.net>
>
> I proposed diffrent fix for this here:
> https://lore.kernel.org/linux-wireless/20240520073210.GA693073@wp.pl/
> but never get feedback if it works on real HW.

I submitted bug reports about this at Debian and on kernel.org's
Bugzilla, but never saw this patch, so obviously could not provide
feedback.

> So I prefer this one, sice it was tested.
>
> Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>

Thanks.

> Martin-Éric and Brandon, could you plase also test patch from
> https://lore.kernel.org/linux-wireless/Zr2gxERA3RL3EwRe@elsanto/
> if it does not break the driver?

I am not currently in a position to test this. I will trust Brandon's
results on this one.

Meanwhile, an entirely unrelated bug crept into the kernel. See
attachments on the above bugzilla report.

Martin-Éric

Re: [PATCH] wifi: iwlegacy: Fix "field-spanning write" warning in il_enqueue_hcmd()

[Kalle Valo]

Ben Hutchings <ben@decadent.org.uk> wrote:

> iwlegacy uses command buffers with a payload size of 320
> bytes (default) or 4092 bytes (huge).  The struct il_device_cmd type
> describes the default buffers and there is no separate type describing
> the huge buffers.
> 
> The il_enqueue_hcmd() function works with both default and huge
> buffers, and has a memcpy() to the buffer payload.  The size of
> this copy may exceed 320 bytes when using a huge buffer, which
> now results in a run-time warning:
> 
>     memcpy: detected field-spanning write (size 1014) of single field "&out_cmd->cmd.payload" at drivers/net/wireless/intel/iwlegacy/common.c:3170 (size 320)
> 
> To fix this:
> 
> - Define a new struct type for huge buffers, with a correctly sized
>   payload field
> - When using a huge buffer in il_enqueue_hcmd(), cast the command
>   buffer pointer to that type when looking up the payload field
> 
> Reported-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
> References: https://bugs.debian.org/1062421
> References: https://bugzilla.kernel.org/show_bug.cgi?id=219124
> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
> Fixes: 54d9469bc515 ("fortify: Add run-time WARN for cross-field memcpy()")
> Tested-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
> Tested-by: Brandon Nielsen <nielsenb@jetfuse.net>
> Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>

Should this patch go wireless tree for v6.12? As this is a regression I think
it should.

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/ZuIhQRi/791vlUhE@decadent.org.uk/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

Re: [PATCH] wifi: iwlegacy: Fix "field-spanning write" warning in il_enqueue_hcmd()

[Stanislaw Gruszka]

On Wed, Sep 18, 2024 at 01:45:57PM +0000, Kalle Valo wrote:
> Ben Hutchings <ben@decadent.org.uk> wrote:
> 
> > iwlegacy uses command buffers with a payload size of 320
> > bytes (default) or 4092 bytes (huge).  The struct il_device_cmd type
> > describes the default buffers and there is no separate type describing
> > the huge buffers.
> > 
> > The il_enqueue_hcmd() function works with both default and huge
> > buffers, and has a memcpy() to the buffer payload.  The size of
> > this copy may exceed 320 bytes when using a huge buffer, which
> > now results in a run-time warning:
> > 
> >     memcpy: detected field-spanning write (size 1014) of single field "&out_cmd->cmd.payload" at drivers/net/wireless/intel/iwlegacy/common.c:3170 (size 320)
> > 
> > To fix this:
> > 
> > - Define a new struct type for huge buffers, with a correctly sized
> >   payload field
> > - When using a huge buffer in il_enqueue_hcmd(), cast the command
> >   buffer pointer to that type when looking up the payload field
> > 
> > Reported-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
> > References: https://bugs.debian.org/1062421
> > References: https://bugzilla.kernel.org/show_bug.cgi?id=219124
> > Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
> > Fixes: 54d9469bc515 ("fortify: Add run-time WARN for cross-field memcpy()")
> > Tested-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
> > Tested-by: Brandon Nielsen <nielsenb@jetfuse.net>
> > Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>
> 
> Should this patch go wireless tree for v6.12? As this is a regression I think
> it should.
It's not driver regression per se, just false positive warning when built
with CONFIG_FORTIFY_SOURCE. But it should go to 6.12 IMHO as fix for
the warning.

Regards
Stanislaw

Re: [PATCH] wifi: iwlegacy: Fix "field-spanning write" warning in il_enqueue_hcmd()

[Kalle Valo]

Stanislaw Gruszka <stf_xl@wp.pl> writes:

> On Wed, Sep 18, 2024 at 01:45:57PM +0000, Kalle Valo wrote:
>
>> Ben Hutchings <ben@decadent.org.uk> wrote:
>> 
>> > iwlegacy uses command buffers with a payload size of 320
>> > bytes (default) or 4092 bytes (huge).  The struct il_device_cmd type
>> > describes the default buffers and there is no separate type describing
>> > the huge buffers.
>> > 
>> > The il_enqueue_hcmd() function works with both default and huge
>> > buffers, and has a memcpy() to the buffer payload.  The size of
>> > this copy may exceed 320 bytes when using a huge buffer, which
>> > now results in a run-time warning:
>> > 
>> >     memcpy: detected field-spanning write (size 1014) of single field "&out_cmd->cmd.payload" at drivers/net/wireless/intel/iwlegacy/common.c:3170 (size 320)
>> > 
>> > To fix this:
>> > 
>> > - Define a new struct type for huge buffers, with a correctly sized
>> >   payload field
>> > - When using a huge buffer in il_enqueue_hcmd(), cast the command
>> >   buffer pointer to that type when looking up the payload field
>> > 
>> > Reported-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
>> > References: https://bugs.debian.org/1062421
>> > References: https://bugzilla.kernel.org/show_bug.cgi?id=219124
>> > Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
>> > Fixes: 54d9469bc515 ("fortify: Add run-time WARN for cross-field memcpy()")
>> > Tested-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
>> > Tested-by: Brandon Nielsen <nielsenb@jetfuse.net>
>> > Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>
>> 
>> Should this patch go wireless tree for v6.12? As this is a regression I think
>> it should.
>
> It's not driver regression per se, just false positive warning when built
> with CONFIG_FORTIFY_SOURCE. But it should go to 6.12 IMHO as fix for
> the warning.

Thanks, I'll then take this to wireless tree.

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Re: [PATCH] wifi: iwlegacy: Fix "field-spanning write" warning in il_enqueue_hcmd()

[Kalle Valo]

Ben Hutchings <ben@decadent.org.uk> wrote:

> iwlegacy uses command buffers with a payload size of 320
> bytes (default) or 4092 bytes (huge).  The struct il_device_cmd type
> describes the default buffers and there is no separate type describing
> the huge buffers.
> 
> The il_enqueue_hcmd() function works with both default and huge
> buffers, and has a memcpy() to the buffer payload.  The size of
> this copy may exceed 320 bytes when using a huge buffer, which
> now results in a run-time warning:
> 
>     memcpy: detected field-spanning write (size 1014) of single field "&out_cmd->cmd.payload" at drivers/net/wireless/intel/iwlegacy/common.c:3170 (size 320)
> 
> To fix this:
> 
> - Define a new struct type for huge buffers, with a correctly sized
>   payload field
> - When using a huge buffer in il_enqueue_hcmd(), cast the command
>   buffer pointer to that type when looking up the payload field
> 
> Reported-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
> References: https://bugs.debian.org/1062421
> References: https://bugzilla.kernel.org/show_bug.cgi?id=219124
> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
> Fixes: 54d9469bc515 ("fortify: Add run-time WARN for cross-field memcpy()")
> Tested-by: Martin-Éric Racine <martin-eric.racine@iki.fi>
> Tested-by: Brandon Nielsen <nielsenb@jetfuse.net>
> Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>

Patch applied to wireless.git, thanks.

d4cdc46ca16a wifi: iwlegacy: Fix "field-spanning write" warning in il_enqueue_hcmd()

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https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches