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);