From: Roger Tseng Date: Fri, 6 Mar 2015 11:36:06 +0800 Subject: [PATCH] mfd: rtsx_usb: prevent DMA from stack Functions rtsx_usb_ep0_read_register() and rtsx_usb_get_card_status() both use arbitrary buffer addresses from arguments directly for DMA and the buffers could be located in stack. This was caught by DMA-API debug check. Fixes this by using double-buffers via kzalloc in both functions to guarantee the validity of DMA buffer. WARNING: CPU: 1 PID: 25 at lib/dma-debug.c:1166 check_for_stack+0x96/0xe0() ehci-pci 0000:00:1a.0: DMA-API: device driver maps memory from stack [addr=ffff8801199e3cef] Modules linked in: rtsx_usb_ms arc4 memstick intel_rapl iosf_mbi rtl8192ce snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel rtl_pci rtl8192c_common snd_hda_controller x86_pkg_temp_thermal snd_hda_codec rtlwifi mac80211 coretemp kvm_intel kvm iTCO_wdt snd_hwdep snd_seq snd_seq_device crct10dif_pclmul iTCO_vendor_support sparse_keymap cfg80211 crc32_pclmul snd_pcm crc32c_intel ghash_clmulni_intel rfkill i2c_i801 snd_timer shpchp snd serio_raw mei_me lpc_ich soundcore mei tpm_tis tpm wmi nfsd auth_rpcgss nfs_acl lockd grace sunrpc i915 rtsx_usb_sdmmc mmc_core 8021q uas garp stp i2c_algo_bit llc mrp drm_kms_helper usb_storage drm rtsx_usb mfd_core r8169 mii video CPU: 1 PID: 25 Comm: kworker/1:2 Not tainted 3.20.0-0.rc0.git7.3.fc22.x86_64 #1 Hardware name: WB WB-B06211/WB-B0621, BIOS EB062IWB V1.0 12/12/2013 Workqueue: events rtsx_usb_ms_handle_req [rtsx_usb_ms] 0000000000000000 000000003d188e66 ffff8801199e3808 ffffffff8187642b 0000000000000000 ffff8801199e3860 ffff8801199e3848 ffffffff810ab39a ffff8801199e3864 ffff8801199e3cef ffff880119b57098 ffff880119b37320 Call Trace: [] dump_stack+0x4c/0x65 [] warn_slowpath_common+0x8a/0xc0 [] warn_slowpath_fmt+0x55/0x70 [] ? _raw_spin_unlock_irqrestore+0x36/0x70 [] check_for_stack+0x96/0xe0 [] debug_dma_map_page+0x104/0x150 [] usb_hcd_map_urb_for_dma+0x646/0x790 [] usb_hcd_submit_urb+0x1d5/0xa90 [] ? mark_held_locks+0x7f/0xc0 [] ? mark_held_locks+0x7f/0xc0 [] ? lockdep_init_map+0x65/0x5d0 [] usb_submit_urb+0x42e/0x5f0 [] usb_start_wait_urb+0x77/0x190 [] ? __kmalloc+0x205/0x2d0 [] usb_control_msg+0xdc/0x130 [] rtsx_usb_ep0_read_register+0x59/0x70 [rtsx_usb] [] ? rtsx_usb_get_rsp+0x41/0x50 [rtsx_usb] [] rtsx_usb_ms_handle_req+0x7ce/0x9c5 [rtsx_usb_ms] Reported-by: Josh Boyer Signed-off-by: Roger Tseng --- drivers/mfd/rtsx_usb.c | 30 ++++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/drivers/mfd/rtsx_usb.c b/drivers/mfd/rtsx_usb.c index ede50244f265..dbd907d7170e 100644 --- a/drivers/mfd/rtsx_usb.c +++ b/drivers/mfd/rtsx_usb.c @@ -196,18 +196,27 @@ EXPORT_SYMBOL_GPL(rtsx_usb_ep0_write_register); int rtsx_usb_ep0_read_register(struct rtsx_ucr *ucr, u16 addr, u8 *data) { u16 value; + u8 *buf; + int ret; if (!data) return -EINVAL; - *data = 0; + + buf = kzalloc(sizeof(u8), GFP_KERNEL); + if (!buf) + return -ENOMEM; addr |= EP0_READ_REG_CMD << EP0_OP_SHIFT; value = swab16(addr); - return usb_control_msg(ucr->pusb_dev, + ret = usb_control_msg(ucr->pusb_dev, usb_rcvctrlpipe(ucr->pusb_dev, 0), RTSX_USB_REQ_REG_OP, USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE, - value, 0, data, 1, 100); + value, 0, buf, 1, 100); + *data = *buf; + + kfree(buf); + return ret; } EXPORT_SYMBOL_GPL(rtsx_usb_ep0_read_register); @@ -288,18 +297,27 @@ static int rtsx_usb_get_status_with_bulk(struct rtsx_ucr *ucr, u16 *status) int rtsx_usb_get_card_status(struct rtsx_ucr *ucr, u16 *status) { int ret; + u16 *buf; if (!status) return -EINVAL; - if (polling_pipe == 0) + if (polling_pipe == 0) { + buf = kzalloc(sizeof(u16), GFP_KERNEL); + if (!buf) + return -ENOMEM; + ret = usb_control_msg(ucr->pusb_dev, usb_rcvctrlpipe(ucr->pusb_dev, 0), RTSX_USB_REQ_POLL, USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE, - 0, 0, status, 2, 100); - else + 0, 0, buf, 2, 100); + *status = *buf; + + kfree(buf); + } else { ret = rtsx_usb_get_status_with_bulk(ucr, status); + } /* usb_control_msg may return positive when success */ if (ret < 0) -- 2.1.0