[PATCH 5.15.y 1/3] KVM: arm64: vgic-its: Add a data length check in vgic_its_save_*

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commit 7fe28d7e68f92cc3d0668b8f2fbdf5c303ac3022 upstream.

In all the vgic_its_save_*() functinos, they do not check whether
the data length is 8 bytes before calling vgic_write_guest_lock.
This patch adds the check. To prevent the kernel from being blown up
when the fault occurs, KVM_BUG_ON() is used. And the other BUG_ON()s
are replaced together.

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Kunkun Jiang <jiangkunkun@xxxxxxxxxx>
[Jing: Update with the new entry read/write helpers]
Signed-off-by: Jing Zhang <jingzhangos@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20241107214137.428439-4-jingzhangos@xxxxxxxxxx
Signed-off-by: Oliver Upton <oliver.upton@xxxxxxxxx>
---
 arch/arm64/kvm/vgic/vgic-its.c | 20 ++++++++------------
 arch/arm64/kvm/vgic/vgic.h     | 24 ++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index 02ab6ab6ba91..bff7c49dfda5 100644
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -2135,7 +2135,6 @@ static int scan_its_table(struct vgic_its *its, gpa_t base, int size, u32 esz,
 static int vgic_its_save_ite(struct vgic_its *its, struct its_device *dev,
 			      struct its_ite *ite, gpa_t gpa, int ite_esz)
 {
-	struct kvm *kvm = its->dev->kvm;
 	u32 next_offset;
 	u64 val;
 
@@ -2144,7 +2143,8 @@ static int vgic_its_save_ite(struct vgic_its *its, struct its_device *dev,
 	       ((u64)ite->irq->intid << KVM_ITS_ITE_PINTID_SHIFT) |
 		ite->collection->collection_id;
 	val = cpu_to_le64(val);
-	return kvm_write_guest_lock(kvm, gpa, &val, ite_esz);
+
+	return vgic_its_write_entry_lock(its, gpa, val, ite_esz);
 }
 
 /**
@@ -2280,7 +2280,6 @@ static int vgic_its_restore_itt(struct vgic_its *its, struct its_device *dev)
 static int vgic_its_save_dte(struct vgic_its *its, struct its_device *dev,
 			     gpa_t ptr, int dte_esz)
 {
-	struct kvm *kvm = its->dev->kvm;
 	u64 val, itt_addr_field;
 	u32 next_offset;
 
@@ -2291,7 +2290,8 @@ static int vgic_its_save_dte(struct vgic_its *its, struct its_device *dev,
 	       (itt_addr_field << KVM_ITS_DTE_ITTADDR_SHIFT) |
 		(dev->num_eventid_bits - 1));
 	val = cpu_to_le64(val);
-	return kvm_write_guest_lock(kvm, ptr, &val, dte_esz);
+
+	return vgic_its_write_entry_lock(its, ptr, val, dte_esz);
 }
 
 /**
@@ -2471,7 +2471,8 @@ static int vgic_its_save_cte(struct vgic_its *its,
 	       ((u64)collection->target_addr << KVM_ITS_CTE_RDBASE_SHIFT) |
 	       collection->collection_id);
 	val = cpu_to_le64(val);
-	return kvm_write_guest_lock(its->dev->kvm, gpa, &val, esz);
+
+	return vgic_its_write_entry_lock(its, gpa, val, esz);
 }
 
 static int vgic_its_restore_cte(struct vgic_its *its, gpa_t gpa, int esz)
@@ -2482,8 +2483,7 @@ static int vgic_its_restore_cte(struct vgic_its *its, gpa_t gpa, int esz)
 	u64 val;
 	int ret;
 
-	BUG_ON(esz > sizeof(val));
-	ret = kvm_read_guest_lock(kvm, gpa, &val, esz);
+	ret = vgic_its_read_entry_lock(its, gpa, &val, esz);
 	if (ret)
 		return ret;
 	val = le64_to_cpu(val);
@@ -2517,7 +2517,6 @@ static int vgic_its_save_collection_table(struct vgic_its *its)
 	u64 baser = its->baser_coll_table;
 	gpa_t gpa = GITS_BASER_ADDR_48_to_52(baser);
 	struct its_collection *collection;
-	u64 val;
 	size_t max_size, filled = 0;
 	int ret, cte_esz = abi->cte_esz;
 
@@ -2541,10 +2540,7 @@ static int vgic_its_save_collection_table(struct vgic_its *its)
 	 * table is not fully filled, add a last dummy element
 	 * with valid bit unset
 	 */
-	val = 0;
-	BUG_ON(cte_esz > sizeof(val));
-	ret = kvm_write_guest_lock(its->dev->kvm, gpa, &val, cte_esz);
-	return ret;
+	return vgic_its_write_entry_lock(its, gpa, 0, cte_esz);
 }
 
 /**
diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h
index 2be4b0759f5b..d2fc5ecb223e 100644
--- a/arch/arm64/kvm/vgic/vgic.h
+++ b/arch/arm64/kvm/vgic/vgic.h
@@ -6,6 +6,7 @@
 #define __KVM_ARM_VGIC_NEW_H__
 
 #include <linux/irqchip/arm-gic-common.h>
+#include <asm/kvm_mmu.h>
 
 #define PRODUCT_ID_KVM		0x4b	/* ASCII code K */
 #define IMPLEMENTER_ARM		0x43b
@@ -126,6 +127,29 @@ static inline bool vgic_irq_is_multi_sgi(struct vgic_irq *irq)
 	return vgic_irq_get_lr_count(irq) > 1;
 }
 
+static inline int vgic_its_read_entry_lock(struct vgic_its *its, gpa_t eaddr,
+					   u64 *eval, unsigned long esize)
+{
+	struct kvm *kvm = its->dev->kvm;
+
+	if (KVM_BUG_ON(esize != sizeof(*eval), kvm))
+		return -EINVAL;
+
+	return kvm_read_guest_lock(kvm, eaddr, eval, esize);
+
+}
+
+static inline int vgic_its_write_entry_lock(struct vgic_its *its, gpa_t eaddr,
+					    u64 eval, unsigned long esize)
+{
+	struct kvm *kvm = its->dev->kvm;
+
+	if (KVM_BUG_ON(esize != sizeof(eval), kvm))
+		return -EINVAL;
+
+	return kvm_write_guest_lock(kvm, eaddr, &eval, esize);
+}
+
 /*
  * This struct provides an intermediate representation of the fields contained
  * in the GICH_VMCR and ICH_VMCR registers, such that code exporting the GIC

base-commit: 0a51d2d4527b43c5e467ffa6897deefeaf499358
-- 
2.47.0.338.g60cca15819-goog





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