ALSA: isa/wavefront: Fix potential Spectre v1 vulnerabilities
diff mbox series

Message ID 20190326183202.GA17285@embeddedor
State New
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Series
  • ALSA: isa/wavefront: Fix potential Spectre v1 vulnerabilities
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Commit Message

Gustavo A. R. Silva March 26, 2019, 6:32 p.m. UTC
header->number and i are indirectly controlled by user-space, hence leading
to a potential exploitation of the Spectre variant 1 vulnerability.

This issue was detected with the help of Smatch:

sound/isa/wavefront/wavefront_synth.c:792 wavefront_send_patch() warn: potential spectre issue 'dev->patch_status' [w] (local cap)
sound/isa/wavefront/wavefront_synth.c:819 wavefront_send_program() warn: potential spectre issue 'dev->prog_status' [w] (local cap)
sound/isa/wavefront/wavefront_synth.c:1197 wavefront_send_alias() warn: potential spectre issue 'dev->sample_status' [w]
sound/isa/wavefront/wavefront_synth.c:1248 wavefront_send_multisample() warn: potential spectre issue 'dev->sample_status' [w]
sound/isa/wavefront/wavefront_synth.c:1548 wavefront_synth_control() warn: potential spectre issue 'dev->sample_status' [r] (local cap)

Fix this by sanitizing header->number and i before using them to index
dev->patch_status, dev->prog_status, dev->sample_status.

Notice that given that speculation windows are large, the policy is
to kill the speculation on the first load and not worry if it can be
completed with a dependent load/store [1].

[1] https://lore.kernel.org/lkml/20180423164740.GY17484@dhcp22.suse.cz/

Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 sound/isa/wavefront/wavefront_synth.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

Comments

Gustavo A. R. Silva April 15, 2019, 7:35 p.m. UTC | #1
Hi all,

Friendly ping:

Who can take this?

Thanks
--
Gustavo

On 3/26/19 1:32 PM, Gustavo A. R. Silva wrote:
> header->number and i are indirectly controlled by user-space, hence leading
> to a potential exploitation of the Spectre variant 1 vulnerability.
> 
> This issue was detected with the help of Smatch:
> 
> sound/isa/wavefront/wavefront_synth.c:792 wavefront_send_patch() warn: potential spectre issue 'dev->patch_status' [w] (local cap)
> sound/isa/wavefront/wavefront_synth.c:819 wavefront_send_program() warn: potential spectre issue 'dev->prog_status' [w] (local cap)
> sound/isa/wavefront/wavefront_synth.c:1197 wavefront_send_alias() warn: potential spectre issue 'dev->sample_status' [w]
> sound/isa/wavefront/wavefront_synth.c:1248 wavefront_send_multisample() warn: potential spectre issue 'dev->sample_status' [w]
> sound/isa/wavefront/wavefront_synth.c:1548 wavefront_synth_control() warn: potential spectre issue 'dev->sample_status' [r] (local cap)
> 
> Fix this by sanitizing header->number and i before using them to index
> dev->patch_status, dev->prog_status, dev->sample_status.
> 
> Notice that given that speculation windows are large, the policy is
> to kill the speculation on the first load and not worry if it can be
> completed with a dependent load/store [1].
> 
> [1] https://lore.kernel.org/lkml/20180423164740.GY17484@dhcp22.suse.cz/
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
>  sound/isa/wavefront/wavefront_synth.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/sound/isa/wavefront/wavefront_synth.c b/sound/isa/wavefront/wavefront_synth.c
> index 0b1e4b34b299..a78e125dfdf9 100644
> --- a/sound/isa/wavefront/wavefront_synth.c
> +++ b/sound/isa/wavefront/wavefront_synth.c
> @@ -31,6 +31,7 @@
>  #include <linux/moduleparam.h>
>  #include <linux/slab.h>
>  #include <linux/module.h>
> +#include <linux/nospec.h>
>  #include <sound/core.h>
>  #include <sound/snd_wavefront.h>
>  #include <sound/initval.h>
> @@ -788,6 +789,8 @@ wavefront_send_patch (snd_wavefront_t *dev, wavefront_patch_info *header)
>  
>  	if (header->number >= ARRAY_SIZE(dev->patch_status))
>  		return -EINVAL;
> +	header->number = array_index_nospec(header->number,
> +					    ARRAY_SIZE(dev->patch_status));
>  
>  	dev->patch_status[header->number] |= WF_SLOT_FILLED;
>  
> @@ -815,6 +818,8 @@ wavefront_send_program (snd_wavefront_t *dev, wavefront_patch_info *header)
>  
>  	if (header->number >= ARRAY_SIZE(dev->prog_status))
>  		return -EINVAL;
> +	header->number = array_index_nospec(header->number,
> +					    ARRAY_SIZE(dev->prog_status));
>  
>  	dev->prog_status[header->number] = WF_SLOT_USED;
>  
> @@ -1194,6 +1199,11 @@ wavefront_send_alias (snd_wavefront_t *dev, wavefront_patch_info *header)
>  		return -EIO;
>  	}
>  
> +	if (header->number >= ARRAY_SIZE(dev->sample_status))
> +		return -EINVAL;
> +	header->number = array_index_nospec(header->number,
> +					    ARRAY_SIZE(dev->sample_status));
> +
>  	dev->sample_status[header->number] = (WF_SLOT_FILLED|WF_ST_ALIAS);
>  
>  	return (0);
> @@ -1245,6 +1255,12 @@ wavefront_send_multisample (snd_wavefront_t *dev, wavefront_patch_info *header)
>  		return -EIO;
>  	}
>  
> +	if (header->number >= ARRAY_SIZE(dev->sample_status)) {
> +		kfree(msample_hdr);
> +		return -EINVAL;
> +	}
> +	header->number = array_index_nospec(header->number,
> +					    ARRAY_SIZE(dev->sample_status));
>  	dev->sample_status[header->number] = (WF_SLOT_FILLED|WF_ST_MULTISAMPLE);
>  
>  	kfree(msample_hdr);
> @@ -1545,6 +1561,7 @@ wavefront_synth_control (snd_wavefront_card_t *acard,
>  			wc->status = EINVAL;
>  			return -EINVAL;
>  		}
> +		i = array_index_nospec(i, WF_MAX_SAMPLE);
>  		wc->rbuf[0] = dev->sample_status[i];
>  		wc->status = 0;
>  		return 0;
>
Takashi Iwai April 15, 2019, 10:34 p.m. UTC | #2
On Mon, 15 Apr 2019 21:35:17 +0200,
 Gustavo A. R. Silva  wrote:
> 
> Hi all,
> 
> Friendly ping:
> 
> Who can take this?

All platforms that support ISA boards are so old and they don't suffer
from Spectre at all.


thanks,

Takashi


> 
> Thanks
> --
> Gustavo
> 
> On 3/26/19 1:32 PM, Gustavo A. R. Silva wrote:
> > header->number and i are indirectly controlled by user-space, hence leading
> > to a potential exploitation of the Spectre variant 1 vulnerability.
> > 
> > This issue was detected with the help of Smatch:
> > 
> > sound/isa/wavefront/wavefront_synth.c:792 wavefront_send_patch() warn: potential spectre issue 'dev->patch_status' [w] (local cap)
> > sound/isa/wavefront/wavefront_synth.c:819 wavefront_send_program() warn: potential spectre issue 'dev->prog_status' [w] (local cap)
> > sound/isa/wavefront/wavefront_synth.c:1197 wavefront_send_alias() warn: potential spectre issue 'dev->sample_status' [w]
> > sound/isa/wavefront/wavefront_synth.c:1248 wavefront_send_multisample() warn: potential spectre issue 'dev->sample_status' [w]
> > sound/isa/wavefront/wavefront_synth.c:1548 wavefront_synth_control() warn: potential spectre issue 'dev->sample_status' [r] (local cap)
> > 
> > Fix this by sanitizing header->number and i before using them to index
> > dev->patch_status, dev->prog_status, dev->sample_status.
> > 
> > Notice that given that speculation windows are large, the policy is
> > to kill the speculation on the first load and not worry if it can be
> > completed with a dependent load/store [1].
> > 
> > [1] https://lore.kernel.org/lkml/20180423164740.GY17484@dhcp22.suse.cz/
> > 
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> > ---
> >  sound/isa/wavefront/wavefront_synth.c | 17 +++++++++++++++++
> >  1 file changed, 17 insertions(+)
> > 
> > diff --git a/sound/isa/wavefront/wavefront_synth.c b/sound/isa/wavefront/wavefront_synth.c
> > index 0b1e4b34b299..a78e125dfdf9 100644
> > --- a/sound/isa/wavefront/wavefront_synth.c
> > +++ b/sound/isa/wavefront/wavefront_synth.c
> > @@ -31,6 +31,7 @@
> >  #include <linux/moduleparam.h>
> >  #include <linux/slab.h>
> >  #include <linux/module.h>
> > +#include <linux/nospec.h>
> >  #include <sound/core.h>
> >  #include <sound/snd_wavefront.h>
> >  #include <sound/initval.h>
> > @@ -788,6 +789,8 @@ wavefront_send_patch (snd_wavefront_t *dev, wavefront_patch_info *header)
> >  
> >  	if (header->number >= ARRAY_SIZE(dev->patch_status))
> >  		return -EINVAL;
> > +	header->number = array_index_nospec(header->number,
> > +					    ARRAY_SIZE(dev->patch_status));
> >  
> >  	dev->patch_status[header->number] |= WF_SLOT_FILLED;
> >  
> > @@ -815,6 +818,8 @@ wavefront_send_program (snd_wavefront_t *dev, wavefront_patch_info *header)
> >  
> >  	if (header->number >= ARRAY_SIZE(dev->prog_status))
> >  		return -EINVAL;
> > +	header->number = array_index_nospec(header->number,
> > +					    ARRAY_SIZE(dev->prog_status));
> >  
> >  	dev->prog_status[header->number] = WF_SLOT_USED;
> >  
> > @@ -1194,6 +1199,11 @@ wavefront_send_alias (snd_wavefront_t *dev, wavefront_patch_info *header)
> >  		return -EIO;
> >  	}
> >  
> > +	if (header->number >= ARRAY_SIZE(dev->sample_status))
> > +		return -EINVAL;
> > +	header->number = array_index_nospec(header->number,
> > +					    ARRAY_SIZE(dev->sample_status));
> > +
> >  	dev->sample_status[header->number] = (WF_SLOT_FILLED|WF_ST_ALIAS);
> >  
> >  	return (0);
> > @@ -1245,6 +1255,12 @@ wavefront_send_multisample (snd_wavefront_t *dev, wavefront_patch_info *header)
> >  		return -EIO;
> >  	}
> >  
> > +	if (header->number >= ARRAY_SIZE(dev->sample_status)) {
> > +		kfree(msample_hdr);
> > +		return -EINVAL;
> > +	}
> > +	header->number = array_index_nospec(header->number,
> > +					    ARRAY_SIZE(dev->sample_status));
> >  	dev->sample_status[header->number] = (WF_SLOT_FILLED|WF_ST_MULTISAMPLE);
> >  
> >  	kfree(msample_hdr);
> > @@ -1545,6 +1561,7 @@ wavefront_synth_control (snd_wavefront_card_t *acard,
> >  			wc->status = EINVAL;
> >  			return -EINVAL;
> >  		}
> > +		i = array_index_nospec(i, WF_MAX_SAMPLE);
> >  		wc->rbuf[0] = dev->sample_status[i];
> >  		wc->status = 0;
> >  		return 0;
> > 
>
Gustavo A. R. Silva April 15, 2019, 10:40 p.m. UTC | #3
On 4/15/19 5:34 PM, Takashi Iwai wrote:
> On Mon, 15 Apr 2019 21:35:17 +0200,
>  Gustavo A. R. Silva  wrote:
>>
>> Hi all,
>>
>> Friendly ping:
>>
>> Who can take this?
> 
> All platforms that support ISA boards are so old and they don't suffer
> from Spectre at all.
> 

Oh okay.

I'll take this info into account for future changes.

Thanks
--
Gustavo

Patch
diff mbox series

diff --git a/sound/isa/wavefront/wavefront_synth.c b/sound/isa/wavefront/wavefront_synth.c
index 0b1e4b34b299..a78e125dfdf9 100644
--- a/sound/isa/wavefront/wavefront_synth.c
+++ b/sound/isa/wavefront/wavefront_synth.c
@@ -31,6 +31,7 @@ 
 #include <linux/moduleparam.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/nospec.h>
 #include <sound/core.h>
 #include <sound/snd_wavefront.h>
 #include <sound/initval.h>
@@ -788,6 +789,8 @@  wavefront_send_patch (snd_wavefront_t *dev, wavefront_patch_info *header)
 
 	if (header->number >= ARRAY_SIZE(dev->patch_status))
 		return -EINVAL;
+	header->number = array_index_nospec(header->number,
+					    ARRAY_SIZE(dev->patch_status));
 
 	dev->patch_status[header->number] |= WF_SLOT_FILLED;
 
@@ -815,6 +818,8 @@  wavefront_send_program (snd_wavefront_t *dev, wavefront_patch_info *header)
 
 	if (header->number >= ARRAY_SIZE(dev->prog_status))
 		return -EINVAL;
+	header->number = array_index_nospec(header->number,
+					    ARRAY_SIZE(dev->prog_status));
 
 	dev->prog_status[header->number] = WF_SLOT_USED;
 
@@ -1194,6 +1199,11 @@  wavefront_send_alias (snd_wavefront_t *dev, wavefront_patch_info *header)
 		return -EIO;
 	}
 
+	if (header->number >= ARRAY_SIZE(dev->sample_status))
+		return -EINVAL;
+	header->number = array_index_nospec(header->number,
+					    ARRAY_SIZE(dev->sample_status));
+
 	dev->sample_status[header->number] = (WF_SLOT_FILLED|WF_ST_ALIAS);
 
 	return (0);
@@ -1245,6 +1255,12 @@  wavefront_send_multisample (snd_wavefront_t *dev, wavefront_patch_info *header)
 		return -EIO;
 	}
 
+	if (header->number >= ARRAY_SIZE(dev->sample_status)) {
+		kfree(msample_hdr);
+		return -EINVAL;
+	}
+	header->number = array_index_nospec(header->number,
+					    ARRAY_SIZE(dev->sample_status));
 	dev->sample_status[header->number] = (WF_SLOT_FILLED|WF_ST_MULTISAMPLE);
 
 	kfree(msample_hdr);
@@ -1545,6 +1561,7 @@  wavefront_synth_control (snd_wavefront_card_t *acard,
 			wc->status = EINVAL;
 			return -EINVAL;
 		}
+		i = array_index_nospec(i, WF_MAX_SAMPLE);
 		wc->rbuf[0] = dev->sample_status[i];
 		wc->status = 0;
 		return 0;