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.gy17...@dhcp22.suse.cz/ > > Cc: sta...@vger.kernel.org > Signed-off-by: Gustavo A. R. Silva <gust...@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; >
