From aeae5b4cd9185b0dc72f6d6102cf45073bfbc974 Mon Sep 17 00:00:00 2001 From: Michal Kazior Date: Mon, 15 Jun 2015 14:46:42 +0300 Subject: [PATCH] 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: [] ioread32+0x40/0x50 ... Call Trace: [] ? ath10k_pci_read32+0x4f/0x70 [ath10k_pci] [] ath10k_reg_value_read+0x90/0xf0 [ath10k_core] [] ? handle_mm_fault+0xa91/0x1050 [] __vfs_read+0x28/0xe0 [] ? security_file_permission+0x84/0xa0 [] ? rw_verify_area+0x53/0x100 [] vfs_read+0x8a/0x140 [] SyS_read+0x49/0xb0 [] ? trace_do_page_fault+0x3c/0xc0 [] system_call_fastpath+0x12/0x71 Reported-by: Ben Greear Signed-off-by: Michal Kazior Signed-off-by: Kalle Valo --- drivers/net/wireless/ath/ath10k/pci.c | 13 +++++++++++++ drivers/net/wireless/ath/ath10k/pci.h | 1 + 2 files changed, 14 insertions(+) diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c index ea656e011a96..41765172297c 100644 --- a/drivers/net/wireless/ath/ath10k/pci.c +++ b/drivers/net/wireless/ath/ath10k/pci.c @@ -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); diff --git a/drivers/net/wireless/ath/ath10k/pci.h b/drivers/net/wireless/ath/ath10k/pci.h index d7696ddc03c4..eea0a0170b00 100644 --- a/drivers/net/wireless/ath/ath10k/pci.h +++ b/drivers/net/wireless/ath/ath10k/pci.h @@ -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 -- 2.20.1