4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai <tiwai@xxxxxxx> commit 69fa6f19b95597618ab30438a27b67ad93daa7c7 upstream. As recently Smatch suggested, one place in HD-audio hwdep ioctl codes may expand the array directly from the user-space value with speculation: sound/pci/hda/hda_local.h:467 get_wcaps() warn: potential spectre issue 'codec->wcaps' As get_wcaps() itself is a fairly frequently called inline function, and there is only one single call with a user-space value, we replace only the latter one to open-code locally with array_index_nospec() hardening in this patch. BugLink: https://marc.info/?l=linux-kernel&m=152411496503418&w=2 Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- sound/pci/hda/hda_hwdep.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/sound/pci/hda/hda_hwdep.c +++ b/sound/pci/hda/hda_hwdep.c @@ -21,6 +21,7 @@ #include <linux/init.h> #include <linux/slab.h> #include <linux/compat.h> +#include <linux/nospec.h> #include <sound/core.h> #include "hda_codec.h" #include "hda_local.h" @@ -51,7 +52,16 @@ static int get_wcap_ioctl(struct hda_cod if (get_user(verb, &arg->verb)) return -EFAULT; - res = get_wcaps(codec, verb >> 24); + /* open-code get_wcaps(verb>>24) with nospec */ + verb >>= 24; + if (verb < codec->core.start_nid || + verb >= codec->core.start_nid + codec->core.num_nodes) { + res = 0; + } else { + verb -= codec->core.start_nid; + verb = array_index_nospec(verb, codec->core.num_nodes); + res = codec->wcaps[verb]; + } if (put_user(res, &arg->res)) return -EFAULT; return 0;
