On 17 January 2017 at 08:45, Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> wrote:
> It's fine if the host driver use PIO mode to transfer the
> vmalloc area buffer but not for DMA mode. The sdio APIs haven't
> provide the capability to tell the caller whether it will use DMA
> to finish the IO transfer or not, so don't give the randomly
> insmoded sdio function driver the possibility to break the kernel.
> Also the APIs shouldn't take the liberty to do a copy for these
> cases and just kick out these requests should be enough.
>
> This issue is observed by doing insmod a downloaded wifi module
> driver and the kernel panic right away. Unfortunately we don't have
> the source code but adding this patch that it proves that the module
> driver was passing on a vmalloc area buffer for sdio APIs.
>
> It could very easy to be reproduced by writing a simple function
> module driver and insmod it, and panic log looks like:
>
> unsigned u8 __aligned(32) buf[PAGE_SIZE];
>
> static int wifi_probe(struct sdio_func *func, const struct
> sdio_device_id *id)
> {
> sdio_claim_host(func);
> sdio_enable_func(func);
> sdio_memcpy_toio(func, 0x0, buf, 0x200);
> }
>
> [ 236.748210] wifi_probe: buf = 0xffffff8000a40b80
> [ 236.748258] swiotlb_tbl_map_single: orig_addr = 0xfffffffff8c40b80,
> tlb_addr = 0xf7eae000 //I added log here
> [ 236.748276] Unable to handle kernel paging request at virtual address
> fffffffff8c40b80
> [ 236.776486] pgd = ffffffc0b3417000
> [ 236.776789] [fffffffff8c40b80] *pgd=00000000b3427003,
> *pud=00000000b3427003, *pmd=0000000000000000
> [ 236.777601] Internal error: Oops: 96000005 [#1] PREEMPT SMP
> [ 236.778093] Modules linked in: drvtst(O+)
> [ 236.778463] CPU: 0 PID: 1918 Comm: insmod Tainted: G O
> 4.4.36 #25
> [ 236.779096] Hardware name: Rockchip RK3399 Evaluation Board v3 edp
> (Android) (DT)
> [ 236.779753] task: ffffffc0e3db0c40 ti: ffffffc0b342c000 task.ti:
> ffffffc0b342c000
> [ 236.780418] PC is at __memcpy+0x100/0x180
> [ 236.780777] LR is at swiotlb_tbl_map_single+0x254/0x274
> [ 236.781237] pc : [<ffffff80083579c0>] lr : [<ffffff800837cf70>]
> ...
>
> [ 236.941392] f460: 3d20726464615f67 6666666666783020
> [ 236.941826] [<ffffff80083579c0>] __memcpy+0x100/0x180
> [ 236.942274] [<ffffff800837dc18>] swiotlb_map_sg_attrs+0xa8/0x170
> [ 236.942810] [<ffffff800809359c>] __swiotlb_map_sg_attrs+0x24/0x8c
> [ 236.943353] [<ffffff800871113c>]
> dw_mci_pre_dma_transfer.isra.16+0xf0/0x11c
> [ 236.943967] [<ffffff80087129cc>] __dw_mci_start_request+0x17c/0x4d0
> [ 236.944520] [<ffffff80087132e0>] dw_mci_request+0xb8/0xf0
> [ 236.945002] [<ffffff80086f8b44>] __mmc_start_request+0x9c/0xc0
> [ 236.945520] [<ffffff80087ae0e8>]
> mmc_start_request.part.17+0x100/0x11c
> [ 236.946097] [<ffffff80086f9c74>] mmc_wait_for_req+0x78/0x1a8
> [ 236.946600] [<ffffff800870421c>] mmc_io_rw_extended+0x27c/0x2fc
> [ 236.947124] [<ffffff8008705800>] sdio_io_rw_ext_helper+0x1e4/0x238
> [ 236.947670] [<ffffff8008705954>] sdio_memcpy_toio+0x24/0x2c
> [ 236.948169] [<ffffff8000a40108>] wifi_probe+0xa8/0x198 [drvtst]
> [ 236.948708] [<ffffff8008704734>] sdio_bus_probe+0xb0/0x140
> [ 236.949195] [<ffffff80084bfd6c>] driver_probe_device+0x118/0x2b0
> [ 236.949724] [<ffffff80084bff68>] __driver_attach+0x64/0x90
> [ 236.950212] [<ffffff80084bee18>] bus_for_each_dev+0x80/0xb0
> [ 236.950706] [<ffffff80084bf8ac>] driver_attach+0x20/0x28
> [ 236.951176] [<ffffff80084bf45c>] bus_add_driver+0xe8/0x1ec
> [ 236.951661] [<ffffff80084c0afc>] driver_register+0x98/0xe4
> [ 236.952147] [<ffffff8008704580>] sdio_register_driver+0x24/0x2c
> [ 236.952675] [<ffffff8000a40228>] wifi_sdio_init+0x30/0x68 [drvtst]
> [ 236.953241] [<ffffff8000a4400c>] wifi_drv_init+0xc/0x38 [drvtst]
> [ 236.953789] [<ffffff8008082ba4>] do_one_initcall+0x17c/0x198
> [ 236.954293] [<ffffff800815e564>] do_init_module+0x60/0x1b8
> [ 236.954779] [<ffffff80081150f0>] load_module+0x1660/0x1a50
> [ 236.955264] [<ffffff800811562c>] SyS_init_module+0x14c/0x180
> [ 236.955765] [<ffffff80080826f0>] el0_svc_naked+0x24/0x28
>
> So the kernel crash since the vmalloc area buffer isn't physical
> continuous and swiotlb couldn't find the correct mapping address
> in fact. Anyway, don't give the chance to panic kernel by using
> sdio APIs.
>
> Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
> ---
>
> drivers/mmc/core/sdio_io.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
> index 406e5f0..cf00805 100644
> --- a/drivers/mmc/core/sdio_io.c
> +++ b/drivers/mmc/core/sdio_io.c
> @@ -10,6 +10,7 @@
> */
>
> #include <linux/export.h>
> +#include <linux/mm.h>
> #include <linux/mmc/host.h>
> #include <linux/mmc/card.h>
> #include <linux/mmc/sdio.h>
> @@ -307,7 +308,7 @@ static int sdio_io_rw_ext_helper(struct sdio_func *func, int write,
> unsigned max_blocks;
> int ret;
>
> - if (!func || (func->num > 7))
> + if (!func || (func->num > 7) || is_vmalloc_addr(buf))
> return -EINVAL;
>
> /* Do the bulk of the transfer using block mode (if supported). */
> --
> 1.9.1
>
>
Actually we need kmalloced buffers. We can't cope with stack buffers either.
Could you please extend the check above to cover this as well.
Moreover we also have those requests going via mmc_io_rw_direct(), we
should validate the buffers for these as well.
Kind regards
Uffe
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