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(unknown [210.73.43.101]) by APP-01 (Coremail) with SMTP id qwCowAB34276T6Vpe_AXCQ--.522S2; Mon, 02 Mar 2026 16:53:14 +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 v2] RISC-V: KVM: Fix use-after-free in kvm_riscv_aia_aplic_has_attr() Date: Mon, 2 Mar 2026 08:53:12 +0000 Message-Id: <20260302085312.1649738-1-xujiakai2025@iscas.ac.cn> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-CM-TRANSID: qwCowAB34276T6Vpe_AXCQ--.522S2 X-Coremail-Antispam: 1UD129KBjvJXoWxWF4fGF45WF4DGrWrGF1rJFb_yoW5Cry7pF WrGFyDA3y5Gwn7GrZIkw1kXr4I9r4YkF1rKr47urWI9rsxtrWIyr9a9ry2qr45AFW8J3sI qF4Yk3s5ur15JF7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPj14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26F4j 6r4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAac4AC62xK8xCEY4vEwIxC4wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC 0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Gr0_Cr 1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IE rcIFxwACI402YVCY1x02628vn2kIc2xKxwCY1x0262kKe7AKxVWUtVW8ZwCY02Avz4vE14 v_GFyl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AK xVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrx kI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v2 6r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8Jw CI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfUnJPEDUUU U X-Originating-IP: [210.73.43.101] X-CM-SenderInfo: 50xmxthndljiysv6x2xfdvhtffof0/1tbiDAUOCWmlOvpQgAAAsS X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260302_005328_020858_12E455F5 X-CRM114-Status: UNSURE ( 9.33 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -2.1 (--) X-Spam-Report: Spam detection software, running on the system "bombadil.infradead.org", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: 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_ [...] Content analysis details: (-2.1 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [159.226.251.21 listed in list.dnswl.org] 0.5 RCVD_IN_VALIDITY_SAFE_BLOCKED RBL: ADMINISTRATOR NOTICE: The query to Validity was blocked. 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[159.226.251.21 listed in bl.score.senderscore.com] -0.0 SPF_HELO_PASS SPF: HELO matches SPF record -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] X-BeenThere: kvm-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kvm-riscv" Errors-To: kvm-riscv-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org 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 = &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 of AIA irqchip") Signed-off-by: Jiakai Xu Signed-off-by: Jiakai Xu --- 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 | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/riscv/kvm/aia_device.c b/arch/riscv/kvm/aia_device.c index b195a93add1ce..ef944d7097d29 100644 --- a/arch/riscv/kvm/aia_device.c +++ b/arch/riscv/kvm/aia_device.c @@ -466,7 +466,9 @@ static int aia_has_attr(struct kvm_device *dev, struct kvm_device_attr *attr) } break; case KVM_DEV_RISCV_AIA_GRP_APLIC: + mutex_lock(&dev->kvm->lock); return kvm_riscv_aia_aplic_has_attr(dev->kvm, attr->attr); + mutex_unlock(&dev->kvm->lock); case KVM_DEV_RISCV_AIA_GRP_IMSIC: return kvm_riscv_aia_imsic_has_attr(dev->kvm, attr->attr); }