linux-kernel - [PATCH] iommu/vt-d: fix shift-out-of-bounds in bug checking

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Message-Id: <1524202195-4656-1-git-send-email-changbin.du@intel.com>
Date:   Fri, 20 Apr 2018 13:29:55 +0800
From:   changbin.du@...el.com
To:     joro@...tes.org
Cc:     iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Changbin Du <changbin.du@...el.com>
Subject: [PATCH] iommu/vt-d: fix shift-out-of-bounds in bug checking

From: Changbin Du <changbin.du@...el.com>

It allows to flush more than 4GB of device TLBs. So the mask should be
64bit wide. UBSAN captured this fault as below.

[    3.760024] ================================================================================
[    3.768440] UBSAN: Undefined behaviour in drivers/iommu/dmar.c:1348:3
[    3.774864] shift exponent 64 is too large for 32-bit type 'int'
[    3.780853] CPU: 2 PID: 0 Comm: swapper/2 Tainted: G     U            4.17.0-rc1+ #89
[    3.788661] Hardware name: Dell Inc. OptiPlex 7040/0Y7WYT, BIOS 1.2.8 01/26/2016
[    3.796034] Call Trace:
[    3.798472]  <IRQ>
[    3.800479]  dump_stack+0x90/0xfb
[    3.803787]  ubsan_epilogue+0x9/0x40
[    3.807353]  __ubsan_handle_shift_out_of_bounds+0x10e/0x170
[    3.812916]  ? qi_flush_dev_iotlb+0x124/0x180
[    3.817261]  qi_flush_dev_iotlb+0x124/0x180
[    3.821437]  iommu_flush_dev_iotlb+0x94/0xf0
[    3.825698]  iommu_flush_iova+0x10b/0x1c0
[    3.829699]  ? fq_ring_free+0x1d0/0x1d0
[    3.833527]  iova_domain_flush+0x25/0x40
[    3.837448]  fq_flush_timeout+0x55/0x160
[    3.841368]  ? fq_ring_free+0x1d0/0x1d0
[    3.845200]  ? fq_ring_free+0x1d0/0x1d0
[    3.849034]  call_timer_fn+0xbe/0x310
[    3.852696]  ? fq_ring_free+0x1d0/0x1d0
[    3.856530]  run_timer_softirq+0x223/0x6e0
[    3.860625]  ? sched_clock+0x5/0x10
[    3.864108]  ? sched_clock+0x5/0x10
[    3.867594]  __do_softirq+0x1b5/0x6f5
[    3.871250]  irq_exit+0xd4/0x130
[    3.874470]  smp_apic_timer_interrupt+0xb8/0x2f0
[    3.879075]  apic_timer_interrupt+0xf/0x20
[    3.883159]  </IRQ>
[    3.885255] RIP: 0010:poll_idle+0x60/0xe7
[    3.889252] RSP: 0018:ffffb1b201943e30 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
[    3.896802] RAX: 0000000080200000 RBX: 000000000000008e RCX: 000000000000001f
[    3.903918] RDX: 0000000000000000 RSI: 000000002819aa06 RDI: 0000000000000000
[    3.911031] RBP: ffff9e93c6b33280 R08: 00000010f717d567 R09: 000000000010d205
[    3.918146] R10: ffffb1b201943df8 R11: 0000000000000001 R12: 00000000e01b169d
[    3.925260] R13: 0000000000000000 R14: ffffffffb12aa400 R15: 0000000000000000
[    3.932382]  cpuidle_enter_state+0xb4/0x470
[    3.936558]  do_idle+0x222/0x310
[    3.939779]  cpu_startup_entry+0x78/0x90
[    3.943693]  start_secondary+0x205/0x2e0
[    3.947607]  secondary_startup_64+0xa5/0xb0
[    3.951783] ================================================================================

Signed-off-by: Changbin Du <changbin.du@...el.com>
---
 drivers/iommu/dmar.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index accf5838..e4ae600 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -1345,7 +1345,7 @@ void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 qdep,
 	struct qi_desc desc;
 
 	if (mask) {
-		BUG_ON(addr & ((1 << (VTD_PAGE_SHIFT + mask)) - 1));
+		BUG_ON(addr & ((1ULL << (VTD_PAGE_SHIFT + mask)) - 1));
 		addr |= (1ULL << (VTD_PAGE_SHIFT + mask - 1)) - 1;
 		desc.high = QI_DEV_IOTLB_ADDR(addr) | QI_DEV_IOTLB_SIZE;
 	} else
-- 
2.7.4