As the recent Smatch warned, one place in OPL3 driver may expand the array directly from the user-space value with speculation: sound/drivers/opl3/opl3_synth.c:476 snd_opl3_set_voice() warn: potential spectre issue 'snd_opl3_regmap'
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 dan.carpenter@oracle.com Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/drivers/opl3/opl3_synth.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/sound/drivers/opl3/opl3_synth.c b/sound/drivers/opl3/opl3_synth.c index ddcc1a325a61..42920a243328 100644 --- a/sound/drivers/opl3/opl3_synth.c +++ b/sound/drivers/opl3/opl3_synth.c @@ -21,6 +21,7 @@
#include <linux/slab.h> #include <linux/export.h> +#include <linux/nospec.h> #include <sound/opl3.h> #include <sound/asound_fm.h>
@@ -448,7 +449,7 @@ static int snd_opl3_set_voice(struct snd_opl3 * opl3, struct snd_dm_fm_voice * v { unsigned short reg_side; unsigned char op_offset; - unsigned char voice_offset; + unsigned char voice_offset, voice_op;
unsigned short opl3_reg; unsigned char reg_val; @@ -473,7 +474,9 @@ static int snd_opl3_set_voice(struct snd_opl3 * opl3, struct snd_dm_fm_voice * v voice_offset = voice->voice - MAX_OPL2_VOICES; } /* Get register offset of operator */ - op_offset = snd_opl3_regmap[voice_offset][voice->op]; + voice_offset = array_index_nospec(voice_offset, MAX_OPL2_VOICES); + voice_op = array_index_nospec(voice->op, 4); + op_offset = snd_opl3_regmap[voice_offset][voice_op];
reg_val = 0x00; /* Set amplitude modulation (tremolo) effect */