From 236cf17c2502007a9d2dda3c39fb0d9a6bd03cc2 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 16 Feb 2016 14:47:31 +0000 Subject: KVM: arm/arm64: vgic: Ensure bitmaps are long enough When we allocate bitmaps in vgic_vcpu_init_maps, we divide the number of bits we need by 8 to figure out how many bytes to allocate. However, bitmap elements are always accessed as unsigned longs, and if we didn't happen to allocate a size such that size % sizeof(unsigned long) == 0, bitmap accesses may go past the end of the allocation. When using KASAN (which does byte-granular access checks), this results in a continuous stream of BUGs whenever these bitmaps are accessed: ============================================================================= BUG kmalloc-128 (Tainted: G B ): kasan: bad access detected ----------------------------------------------------------------------------- INFO: Allocated in vgic_init.part.25+0x55c/0x990 age=7493 cpu=3 pid=1730 INFO: Slab 0xffffffbde6d5da40 objects=16 used=15 fp=0xffffffc935769700 flags=0x4000000000000080 INFO: Object 0xffffffc935769500 @offset=1280 fp=0x (null) Bytes b4 ffffffc9357694f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object ffffffc935769500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object ffffffc935769510: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object ffffffc935769520: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object ffffffc935769530: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object ffffffc935769540: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object ffffffc935769550: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object ffffffc935769560: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object ffffffc935769570: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Padding ffffffc9357695b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Padding ffffffc9357695c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Padding ffffffc9357695d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Padding ffffffc9357695e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Padding ffffffc9357695f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ CPU: 3 PID: 1740 Comm: kvm-vcpu-0 Tainted: G B 4.4.0+ #17 Hardware name: ARM Juno development board (r1) (DT) Call trace: [] dump_backtrace+0x0/0x280 [] show_stack+0x14/0x20 [] dump_stack+0x100/0x188 [] print_trailer+0xfc/0x168 [] object_err+0x3c/0x50 [] kasan_report_error+0x244/0x558 [] __asan_report_load8_noabort+0x48/0x50 [] __bitmap_or+0xc0/0xc8 [] kvm_vgic_flush_hwstate+0x1bc/0x650 [] kvm_arch_vcpu_ioctl_run+0x2ec/0xa60 [] kvm_vcpu_ioctl+0x474/0xa68 [] do_vfs_ioctl+0x5b8/0xcb0 [] SyS_ioctl+0x8c/0xa0 [] el0_svc_naked+0x24/0x28 Memory state around the buggy address: ffffffc935769400: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffffffc935769480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffffffc935769500: 04 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffffffc935769580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffffffc935769600: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== Fix the issue by always allocating a multiple of sizeof(unsigned long), as we do elsewhere in the vgic code. Fixes: c1bfb577a ("arm/arm64: KVM: vgic: switch to dynamic allocation") Cc: stable@vger.kernel.org Acked-by: Marc Zyngier Acked-by: Christoffer Dall Signed-off-by: Mark Rutland Signed-off-by: Marc Zyngier --- virt/kvm/arm/vgic.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 043032c6a5a4..00429b392c61 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -1875,8 +1875,8 @@ void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) static int vgic_vcpu_init_maps(struct kvm_vcpu *vcpu, int nr_irqs) { struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu; - - int sz = (nr_irqs - VGIC_NR_PRIVATE_IRQS) / 8; + int nr_longs = BITS_TO_LONGS(nr_irqs - VGIC_NR_PRIVATE_IRQS); + int sz = nr_longs * sizeof(unsigned long); vgic_cpu->pending_shared = kzalloc(sz, GFP_KERNEL); vgic_cpu->active_shared = kzalloc(sz, GFP_KERNEL); vgic_cpu->pend_act_shared = kzalloc(sz, GFP_KERNEL); -- cgit v1.2.3-59-g8ed1b From 1d6a821277aaa0cdd666278aaff93298df313d41 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 15 Feb 2016 17:04:04 +0000 Subject: arm/arm64: KVM: Feed initialized memory to MMIO accesses On an MMIO access, we always copy the on-stack buffer info the shared "run" structure, even if this is a read access. This ends up leaking up to 8 bytes of uninitialized memory into userspace, depending on the size of the access. An obvious fix for this one is to only perform the copy if this is an actual write. Reviewed-by: Christoffer Dall Signed-off-by: Marc Zyngier --- arch/arm/kvm/mmio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c index 7f33b2056ae6..0f6600f05137 100644 --- a/arch/arm/kvm/mmio.c +++ b/arch/arm/kvm/mmio.c @@ -206,7 +206,8 @@ int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run, run->mmio.is_write = is_write; run->mmio.phys_addr = fault_ipa; run->mmio.len = len; - memcpy(run->mmio.data, data_buf, len); + if (is_write) + memcpy(run->mmio.data, data_buf, len); if (!ret) { /* We handled the access successfully in the kernel. */ -- cgit v1.2.3-59-g8ed1b From fd451b90e78c4178bcfc5072f2b2b637500c109a Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 17 Feb 2016 10:25:05 +0000 Subject: arm64: KVM: vgic-v3: Restore ICH_APR0Rn_EL2 before ICH_APR1Rn_EL2 The GICv3 architecture spec says: Writing to the active priority registers in any order other than the following order will result in UNPREDICTABLE behavior: - ICH_AP0R_EL2. - ICH_AP1R_EL2. So let's not pointlessly go against the rule... Acked-by: Christoffer Dall Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp/vgic-v3-sr.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/arch/arm64/kvm/hyp/vgic-v3-sr.c b/arch/arm64/kvm/hyp/vgic-v3-sr.c index 9142e082f5f3..5dd2a26444ec 100644 --- a/arch/arm64/kvm/hyp/vgic-v3-sr.c +++ b/arch/arm64/kvm/hyp/vgic-v3-sr.c @@ -147,16 +147,6 @@ void __hyp_text __vgic_v3_restore_state(struct kvm_vcpu *vcpu) max_lr_idx = vtr_to_max_lr_idx(val); nr_pri_bits = vtr_to_nr_pri_bits(val); - switch (nr_pri_bits) { - case 7: - write_gicreg(cpu_if->vgic_ap1r[3], ICH_AP1R3_EL2); - write_gicreg(cpu_if->vgic_ap1r[2], ICH_AP1R2_EL2); - case 6: - write_gicreg(cpu_if->vgic_ap1r[1], ICH_AP1R1_EL2); - default: - write_gicreg(cpu_if->vgic_ap1r[0], ICH_AP1R0_EL2); - } - switch (nr_pri_bits) { case 7: write_gicreg(cpu_if->vgic_ap0r[3], ICH_AP0R3_EL2); @@ -167,6 +157,16 @@ void __hyp_text __vgic_v3_restore_state(struct kvm_vcpu *vcpu) write_gicreg(cpu_if->vgic_ap0r[0], ICH_AP0R0_EL2); } + switch (nr_pri_bits) { + case 7: + write_gicreg(cpu_if->vgic_ap1r[3], ICH_AP1R3_EL2); + write_gicreg(cpu_if->vgic_ap1r[2], ICH_AP1R2_EL2); + case 6: + write_gicreg(cpu_if->vgic_ap1r[1], ICH_AP1R1_EL2); + default: + write_gicreg(cpu_if->vgic_ap1r[0], ICH_AP1R0_EL2); + } + switch (max_lr_idx) { case 15: write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(15)], ICH_LR15_EL2); -- cgit v1.2.3-59-g8ed1b