[PATCH v3] Bluetooth: btmrvl: fix slab-out-of-bounds access in btmrvl_sdio

From: Ricky Liang
Date: Tue Jun 28 2016 - 03:07:39 EST


Kasan reported slab-out-of-bounds access in btmrvl_sdio:

[ 33.055400] ==================================================================
[ 33.062585] BUG: KASAN: slab-out-of-bounds in memcpy+0x24/0x50 at addr ffffffc0d89b4a00
[ 33.070529] Read of size 256 by task btmrvl_main_ser/3576
[ 33.075885] =============================================================================
[ 33.084002] BUG kmalloc-256 (Tainted: G B ): kasan: bad access detected
[ 33.091511] -----------------------------------------------------------------------------
<snip...>
[ 33.413498] Call trace:
[ 33.415928] [<ffffffc00020a440>] dump_backtrace+0x0/0x190
[ 33.421288] [<ffffffc00020a5ec>] show_stack+0x1c/0x28
[ 33.426305] [<ffffffc000b3288c>] dump_stack+0xa0/0xf8
[ 33.431320] [<ffffffc000396130>] print_trailer+0x158/0x16c
[ 33.436765] [<ffffffc0003962cc>] object_err+0x48/0x5c
[ 33.441780] [<ffffffc00039be24>] kasan_report+0x344/0x510
[ 33.447141] [<ffffffc00039afd8>] __asan_loadN+0x20/0x150
[ 33.452413] [<ffffffc00039b60c>] memcpy+0x20/0x50
[ 33.457084] [<ffffffc000595fcc>] swiotlb_tbl_map_single+0x2ec/0x310
[ 33.463305] [<ffffffc000596b54>] map_single+0x24/0x30
[ 33.468320] [<ffffffc0005970c8>] swiotlb_map_sg_attrs+0xec/0x21c
[ 33.474286] [<ffffffc000219d4c>] __swiotlb_map_sg_attrs+0x48/0xec
[ 33.480339] [<ffffffc0008ea610>] msdc_prepare_data.isra.11+0xf0/0x11c
[ 33.486733] [<ffffffc0008ecbd0>] msdc_ops_request+0x74/0xf0
[ 33.492266] [<ffffffc0008c6b38>] __mmc_start_request+0x78/0x8c
[ 33.498057] [<ffffffc0008c6d6c>] mmc_start_request+0x220/0x240
[ 33.503848] [<ffffffc0008c6e04>] mmc_wait_for_req+0x78/0x250
[ 33.509468] [<ffffffc0008d70fc>] mmc_io_rw_extended+0x2ec/0x388
[ 33.515347] [<ffffffc0008d8fc0>] sdio_io_rw_ext_helper+0x160/0x268
[ 33.521483] [<ffffffc0008d93fc>] sdio_writesb+0x40/0x50
[ 33.526677] [<ffffffbffc338b38>] btmrvl_sdio_host_to_card+0x124/0x1bc [btmrvl_sdio]
[ 33.534283] [<ffffffbffc3290a0>] btmrvl_service_main_thread+0x384/0x428 [btmrvl]
[ 33.541626] [<ffffffc0002518e8>] kthread+0x140/0x158
[ 33.546550] Memory state around the buggy address:
[ 33.551305] ffffffc0d89b4980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 33.558474] ffffffc0d89b4a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 33.565643] >ffffffc0d89b4a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
[ 33.572809] ^
[ 33.579889] ffffffc0d89b4b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 33.587055] ffffffc0d89b4b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 33.594221] ==================================================================

The cause of this is that btmrvl_sdio_host_to_card can access memory region
out of its allocated space due to:

1. the requested block size is smaller than SDIO_BLOCK_SIZE, and/or
2. the allocated memory is not BTSDIO_DMA_ALIGN-aligned.

This patch fixes the issue by allocating a buffer which is big enough for
SDIO_BLOCK_SIZE transfer and/or BTSDIO_DMA_ALIGN address relocation.

CC: Wei-Ning Huang <wnhuang@xxxxxxxxxxxx>
CC: Daniel Kurtz <djkurtz@xxxxxxxxxxxx>
CC: Amitkumar Karwar <akarwar@xxxxxxxxxxx>

Signed-off-by: Ricky Liang <jcliang@xxxxxxxxxxxx>
---
drivers/bluetooth/btmrvl_sdio.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/bluetooth/btmrvl_sdio.c b/drivers/bluetooth/btmrvl_sdio.c
index f425ddf..b7c3928 100644
--- a/drivers/bluetooth/btmrvl_sdio.c
+++ b/drivers/bluetooth/btmrvl_sdio.c
@@ -1071,7 +1071,6 @@ static int btmrvl_sdio_host_to_card(struct btmrvl_private *priv,
{
struct btmrvl_sdio_card *card = priv->btmrvl_dev.card;
int ret = 0;
- int buf_block_len;
int blksz;
int i = 0;
u8 *buf = NULL;
@@ -1083,9 +1082,13 @@ static int btmrvl_sdio_host_to_card(struct btmrvl_private *priv,
return -EINVAL;
}

+ blksz = DIV_ROUND_UP(nb, SDIO_BLOCK_SIZE) * SDIO_BLOCK_SIZE;
+
buf = payload;
- if ((unsigned long) payload & (BTSDIO_DMA_ALIGN - 1)) {
- tmpbufsz = ALIGN_SZ(nb, BTSDIO_DMA_ALIGN);
+ if ((unsigned long) payload & (BTSDIO_DMA_ALIGN - 1) ||
+ nb < blksz) {
+ tmpbufsz = ALIGN_SZ(blksz, BTSDIO_DMA_ALIGN) +
+ BTSDIO_DMA_ALIGN;
tmpbuf = kzalloc(tmpbufsz, GFP_KERNEL);
if (!tmpbuf)
return -ENOMEM;
@@ -1093,15 +1096,12 @@ static int btmrvl_sdio_host_to_card(struct btmrvl_private *priv,
memcpy(buf, payload, nb);
}

- blksz = SDIO_BLOCK_SIZE;
- buf_block_len = DIV_ROUND_UP(nb, blksz);
-
sdio_claim_host(card->func);

do {
/* Transfer data to card */
ret = sdio_writesb(card->func, card->ioport, buf,
- buf_block_len * blksz);
+ blksz);
if (ret < 0) {
i++;
BT_ERR("i=%d writesb failed: %d", i, ret);
--
2.1.2