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(unknown [210.73.43.101]) by APP-01 (Coremail) with SMTP id qwCowABXw24pkKVpxM0bCQ--.814S2; Mon, 02 Mar 2026 21:27:05 +0800 (CST) From: Jiakai Xu To: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org Cc: Alexandre Ghiti , Albert Ou , Palmer Dabbelt , Paul Walmsley , Atish Patra , Anup Patel , Jiakai Xu , Jiakai Xu Subject: [PATCH v3] RISC-V: KVM: Fix use-after-free in kvm_riscv_aia_aplic_has_attr() Date: Mon, 2 Mar 2026 13:27:03 +0000 Message-Id: <20260302132703.1721415-1-xujiakai2025@iscas.ac.cn> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: qwCowABXw24pkKVpxM0bCQ--.814S2 X-Coremail-Antispam: 1UD129KBjvJXoWxWF4fGF45WF4DGrWrGF1rJFb_yoWrJw1xpF WrCFyDArW5Gw1xGrZxtw1kXw429r4Yk3W3GrWUWrWI9rsxtrWxtr9a9ryjvr4YyFW8Jasa qF4Ykas5ur45JF7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBE14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r4j6ryUM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s 0DM2vYz4IE04k24VAvwVAKI4IrM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI 64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r106r15McIj6I8E87Iv67AKxVW8JVWxJw Am72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAG YxC7M4IIrI8v6xkF7I0E8cxan2IY04v7MxkF7I0En4kS14v26r1q6r43MxkIecxEwVAFwV W5GwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v2 6r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2 Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_ Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMI IF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUVc_fUUUUU = X-CM-SenderInfo: 50xmxthndljiysv6x2xfdvhtffof0/1tbiDAcOCWmljDcJNwAAsF Content-Type: text/plain; charset="utf-8" Fuzzer reports a KASAN use-after-free bug triggered by a race between KVM_HAS_DEVICE_ATTR and KVM_SET_DEVICE_ATTR ioctls on the AIA device. The root cause is that aia_has_attr() invokes kvm_riscv_aia_aplic_has_attr() without holding dev->kvm->lock, while a concurrent aia_set_attr() may call aia_init() under that lock. When aia_init() fails after kvm_riscv_aia_aplic_init() has succeeded, it calls kvm_riscv_aia_aplic_cleanup() in its fail_cleanup_imsics path, which frees both aplic_state and aplic_state->irqs. The concurrent has_attr path can then dereference the freed aplic->irqs in aplic_read_pending(): irqd =3D &aplic->irqs[irq]; /* UAF here */ KASAN report: BUG: KASAN: slab-use-after-free in aplic_read_pending arch/riscv/kvm/aia_aplic.c:119 [inline] BUG: KASAN: slab-use-after-free in aplic_read_pending_word arch/riscv/kvm/aia_aplic.c:351 [inline] BUG: KASAN: slab-use-after-free in aplic_mmio_read_offset arch/riscv/kvm/aia_aplic.c:406 Read of size 8 at addr ff600000ba965d58 by task 9498 Call Trace: aplic_read_pending arch/riscv/kvm/aia_aplic.c:119 [inline] aplic_read_pending_word arch/riscv/kvm/aia_aplic.c:351 [inline] aplic_mmio_read_offset arch/riscv/kvm/aia_aplic.c:406 kvm_riscv_aia_aplic_has_attr arch/riscv/kvm/aia_aplic.c:566 aia_has_attr arch/riscv/kvm/aia_device.c:469 allocated by task 9473: kvm_riscv_aia_aplic_init arch/riscv/kvm/aia_aplic.c:583 aia_init arch/riscv/kvm/aia_device.c:248 [inline] aia_set_attr arch/riscv/kvm/aia_device.c:334 freed by task 9473: kvm_riscv_aia_aplic_cleanup arch/riscv/kvm/aia_aplic.c:644 aia_init arch/riscv/kvm/aia_device.c:292 [inline] aia_set_attr arch/riscv/kvm/aia_device.c:334 Fix this race by acquiring dev->kvm->lock in aia_has_attr() before calling kvm_riscv_aia_aplic_has_attr(), consistent with the locking pattern used in aia_get_attr() and aia_set_attr(). Fixes: 289a007b98b06d ("RISC-V: KVM: Expose APLIC registers as attributes o= f AIA irqchip") Signed-off-by: Jiakai Xu Signed-off-by: Jiakai Xu Reviewed-by: Anup Patel --- V2 -> V3: - Fixed incorrect locking pattern in aia_has_attr(): avoid returning while holding dev->kvm->lock by storing the return value in a local variable, unlocking, and then returning. V1 -> V2: - Fixed the race by adding locking in aia_has_attr() instead of introducing a new validation function, as suggested by Anup Patel. --- arch/riscv/kvm/aia_device.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/riscv/kvm/aia_device.c b/arch/riscv/kvm/aia_device.c index b195a93add1ce..0722cbaed5ec9 100644 --- a/arch/riscv/kvm/aia_device.c +++ b/arch/riscv/kvm/aia_device.c @@ -437,7 +437,7 @@ static int aia_get_attr(struct kvm_device *dev, struct = kvm_device_attr *attr) =20 static int aia_has_attr(struct kvm_device *dev, struct kvm_device_attr *at= tr) { - int nr_vcpus; + int nr_vcpus, r =3D -ENXIO; =20 switch (attr->group) { case KVM_DEV_RISCV_AIA_GRP_CONFIG: @@ -466,12 +466,15 @@ static int aia_has_attr(struct kvm_device *dev, struc= t kvm_device_attr *attr) } break; case KVM_DEV_RISCV_AIA_GRP_APLIC: - return kvm_riscv_aia_aplic_has_attr(dev->kvm, attr->attr); + mutex_lock(&dev->kvm->lock); + r =3D kvm_riscv_aia_aplic_has_attr(dev->kvm, attr->attr); + mutex_unlock(&dev->kvm->lock); + return r; case KVM_DEV_RISCV_AIA_GRP_IMSIC: return kvm_riscv_aia_imsic_has_attr(dev->kvm, attr->attr); } =20 - return -ENXIO; + return r; } =20 struct kvm_device_ops kvm_riscv_aia_device_ops =3D { --=20 2.34.1