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Commit aeae5b4c authored by Michal Kazior's avatar Michal Kazior Committed by Kalle Valo
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ath10k: prevent debugfs mmio access crash kernel 



It was possible to force an out of bounds MMIO
read/write via debugfs. E.g. on QCA988X this could
be triggered with:

 echo 0x2080e0 | tee /sys/kernel/debug/ieee80211/*/ath10k/reg_addr
 cat /sys/kernel/debug/ieee80211/*/ath10k/reg_value

 BUG: unable to handle kernel paging request at ffffc90001e080e0
 IP: [<ffffffff8135c860>] ioread32+0x40/0x50
 ...
 Call Trace:
  [<ffffffffa00d0c7f>] ? ath10k_pci_read32+0x4f/0x70 [ath10k_pci]
  [<ffffffffa0080f50>] ath10k_reg_value_read+0x90/0xf0 [ath10k_core]
  [<ffffffff8115c2c1>] ? handle_mm_fault+0xa91/0x1050
  [<ffffffff81189758>] __vfs_read+0x28/0xe0
  [<ffffffff812e4694>] ? security_file_permission+0x84/0xa0
  [<ffffffff81189ce3>] ? rw_verify_area+0x53/0x100
  [<ffffffff81189e1a>] vfs_read+0x8a/0x140
  [<ffffffff8118acb9>] SyS_read+0x49/0xb0
  [<ffffffff8104e39c>] ? trace_do_page_fault+0x3c/0xc0
  [<ffffffff8196596e>] system_call_fastpath+0x12/0x71

Reported-by: default avatarBen Greear <greearb@candelatech.com>
Signed-off-by: default avatarMichal Kazior <michal.kazior@tieto.com>
Signed-off-by: default avatarKalle Valo <kvalo@qca.qualcomm.com>
parent c702534a

drivers/net/wireless/ath/ath10k/pci.c

+13 −0
Original line number Diff line number Diff line
@@ -479,6 +479,12 @@ void ath10k_pci_write32(struct ath10k *ar, u32 offset, u32 value) 
	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);

	int ret;



	if (unlikely(offset + sizeof(value) > ar_pci->mem_len)) {

		ath10k_warn(ar, "refusing to write mmio out of bounds at 0x%08x - 0x%08zx (max 0x%08zx)\n",

			    offset, offset + sizeof(value), ar_pci->mem_len);

		return;

	}



	ret = ath10k_pci_wake(ar);

	if (ret) {

		ath10k_warn(ar, "failed to wake target for write32 of 0x%08x at 0x%08x: %d\n",
@@ -496,6 +502,12 @@ u32 ath10k_pci_read32(struct ath10k *ar, u32 offset) 
	u32 val;

	int ret;



	if (unlikely(offset + sizeof(val) > ar_pci->mem_len)) {

		ath10k_warn(ar, "refusing to read mmio out of bounds at 0x%08x - 0x%08zx (max 0x%08zx)\n",

			    offset, offset + sizeof(val), ar_pci->mem_len);

		return 0;

	}



	ret = ath10k_pci_wake(ar);

	if (ret) {

		ath10k_warn(ar, "failed to wake target for read32 at 0x%08x: %d\n",
@@ -2679,6 +2691,7 @@ static int ath10k_pci_claim(struct ath10k *ar) 
	pci_set_master(pdev);



	/* Arrange for access to Target SoC registers. */

	ar_pci->mem_len = pci_resource_len(pdev, BAR_NUM);

	ar_pci->mem = pci_iomap(pdev, BAR_NUM, 0);

	if (!ar_pci->mem) {

		ath10k_err(ar, "failed to iomap BAR%d\n", BAR_NUM);

drivers/net/wireless/ath/ath10k/pci.h

+1 −0
Original line number Diff line number Diff line
@@ -162,6 +162,7 @@ struct ath10k_pci { 
	struct device *dev;

	struct ath10k *ar;

	void __iomem *mem;

	size_t mem_len;



	/*

	 * Number of MSI interrupts granted, 0 --> using legacy PCI line