From: Gustavo A. R. Silva Date: Wed, 20 Mar 2019 21:15:24 +0000 (-0500) Subject: ALSA: rawmidi: Fix potential Spectre v1 vulnerability X-Git-Tag: v5.1-rc3~24^2~10 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2b1d9c8f87235f593826b9cf46ec10247741fff9;p=thirdparty%2Fkernel%2Flinux.git ALSA: rawmidi: Fix potential Spectre v1 vulnerability info->stream is 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/core/rawmidi.c:604 __snd_rawmidi_info_select() warn: potential spectre issue 'rmidi->streams' [r] (local cap) Fix this by sanitizing info->stream before using it to index rmidi->streams. 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 Signed-off-by: Takashi Iwai --- diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c index ee601d7f09269..c0690d1ecd55c 100644 --- a/sound/core/rawmidi.c +++ b/sound/core/rawmidi.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include #include @@ -601,6 +602,7 @@ static int __snd_rawmidi_info_select(struct snd_card *card, return -ENXIO; if (info->stream < 0 || info->stream > 1) return -EINVAL; + info->stream = array_index_nospec(info->stream, 2); pstr = &rmidi->streams[info->stream]; if (pstr->substream_count == 0) return -ENOENT;