From 31ba7f2f7d0e7de013392731eefbb959d91cd3be Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 24 Apr 2018 08:04:41 +0200 Subject: [PATCH] ALSA: rme9652: Hardening for potential Spectre v1 commit f526afcd8f71945c23ce581d7864ace93de8a4f7 upstream. As recently Smatch suggested, one place in RME9652 driver may expand the array directly from the user-space value with speculation: sound/pci/rme9652/rme9652.c:2074 snd_rme9652_channel_info() warn: potential spectre issue 'rme9652->channel_map' (local cap) This patch puts array_index_nospec() for hardening against it. BugLink: https://marc.info/?l=linux-kernel&m=152411496503418&w=2 Reported-by: Dan Carpenter Signed-off-by: Takashi Iwai [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- sound/pci/rme9652/rme9652.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/sound/pci/rme9652/rme9652.c b/sound/pci/rme9652/rme9652.c index 1d9be90f7748..25f497c46d04 100644 --- a/sound/pci/rme9652/rme9652.c +++ b/sound/pci/rme9652/rme9652.c @@ -35,6 +35,7 @@ #include #include +#include static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */ static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */ @@ -2059,9 +2060,10 @@ static int snd_rme9652_channel_info(struct snd_pcm_substream *substream, if (snd_BUG_ON(info->channel >= RME9652_NCHANNELS)) return -EINVAL; - if ((chn = rme9652->channel_map[info->channel]) < 0) { + chn = rme9652->channel_map[array_index_nospec(info->channel, + RME9652_NCHANNELS)]; + if (chn < 0) return -EINVAL; - } info->offset = chn * RME9652_CHANNEL_BUFFER_BYTES; info->first = 0;