[PATCH 3.16 227/328] ALSA: bebob: use address returned by kmalloc() instead of kernel stack for streaming DMA mapping

Ben Hutchings
2018-12-09T21:58:13Z

From: Takashi Sakamoto <o-takashi@sakamocchi.jp>

commit 493626f2d87a74e6dbea1686499ed6e7e600484e upstream.

When executing 'fw_run_transaction()' with 'TCODE_WRITE_BLOCK_REQUEST',
an address of 'payload' argument is used for streaming DMA mapping by
'firewire_ohci' module if 'size' argument is larger than 8 byte.
Although in this case the address should not be on kernel stack, current
implementation of ALSA bebob driver uses data in kernel stack for a cue
to boot M-Audio devices. This often brings unexpected result, especially
for a case of CONFIG_VMAP_STACK=y.

This commit fixes the bug.

Reference: https://bugzilla.kernel.org/show_bug.cgi?id=201021
Reference: https://forum.manjaro.org/t/firewire-m-audio-410-driver-wont-load-firmware/51165
Fixes: a2b2a7798fb6('ALSA: bebob: Send a cue to load firmware for M-Audio Firewire series')
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
sound/firewire/bebob/bebob_maudio.c | 24 ++++++++++++++----------
1 file changed, 14 insertions(+), 10 deletions(-)

--- a/sound/firewire/bebob/bebob_maudio.c
+++ b/sound/firewire/bebob/bebob_maudio.c
@@ -96,17 +96,13 @@ int snd_bebob_maudio_load_firmware(struc
struct fw_device *device = fw_parent_device(unit);
int err, rcode;
u64 date;
- __le32 cues[3] = {
- cpu_to_le32(MAUDIO_BOOTLOADER_CUE1),
- cpu_to_le32(MAUDIO_BOOTLOADER_CUE2),
- cpu_to_le32(MAUDIO_BOOTLOADER_CUE3)
- };
+ __le32 *cues;

/* check date of software used to build */
err = snd_bebob_read_block(unit, INFO_OFFSET_SW_DATE,
&date, sizeof(u64));
if (err < 0)
- goto end;
+ return err;
/*
* firmware version 5058 or later has date later than "20070401", but
* 'date' is not null-terminated.
@@ -114,20 +110,28 @@ int snd_bebob_maudio_load_firmware(struc
if (date < 0x3230303730343031LL) {
dev_err(&unit->device,
"Use firmware version 5058 or later\n");
- err = -ENOSYS;
- goto end;
+ return -ENXIO;
}

+ cues = kmalloc_array(3, sizeof(*cues), GFP_KERNEL);
+ if (!cues)
+ return -ENOMEM;
+
+ cues[0] = cpu_to_le32(MAUDIO_BOOTLOADER_CUE1);
+ cues[1] = cpu_to_le32(MAUDIO_BOOTLOADER_CUE2);
+ cues[2] = cpu_to_le32(MAUDIO_BOOTLOADER_CUE3);
+
rcode = fw_run_transaction(device->card, TCODE_WRITE_BLOCK_REQUEST,
device->node_id, device->generation,
device->max_speed, BEBOB_ADDR_REG_REQ,
- cues, sizeof(cues));
+ cues, 3 * sizeof(*cues));
+ kfree(cues);
if (rcode != RCODE_COMPLETE) {
dev_err(&unit->device,
"Failed to send a cue to load firmware\n");
err = -EIO;
}
-end:
+
return err;
}