FAILED: patch "[PATCH] KVM: arm64: Fix buffer overflow in kvm_arm_set_fw_reg()" failed to apply to 5.10-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x a25bc8486f9c01c1af6b6c5657234b2eee2c39d6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023042350-coveted-collapse-44f5@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

a25bc8486f9c ("KVM: arm64: Fix buffer overflow in kvm_arm_set_fw_reg()")
85fbe08e4da8 ("KVM: arm64: Factor out firmware register handling from psci.c")
1ebdbeb03efe ("Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From a25bc8486f9c01c1af6b6c5657234b2eee2c39d6 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Date: Wed, 19 Apr 2023 13:16:13 +0300
Subject: [PATCH] KVM: arm64: Fix buffer overflow in kvm_arm_set_fw_reg()

The KVM_REG_SIZE() comes from the ioctl and it can be a power of two
between 0-32768 but if it is more than sizeof(long) this will corrupt
memory.

Fixes: 99adb567632b ("KVM: arm/arm64: Add save/restore support for firmware workaround state")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Reviewed-by: Steven Price <steven.price@xxxxxxx>
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
Reviewed-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/4efbab8c-640f-43b2-8ac6-6d68e08280fe@kili.mountain
Signed-off-by: Oliver Upton <oliver.upton@xxxxxxxxx>

diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
index 5da884e11337..c4b4678bc4a4 100644
--- a/arch/arm64/kvm/hypercalls.c
+++ b/arch/arm64/kvm/hypercalls.c
@@ -397,6 +397,8 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	u64 val;
 	int wa_level;
 
+	if (KVM_REG_SIZE(reg->id) != sizeof(val))
+		return -ENOENT;
 	if (copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id)))
 		return -EFAULT;