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(unknown [210.73.43.101]) by APP-05 (Coremail) with SMTP id zQCowAAntwqkFLJpB6U4Cg--.65391S3; Thu, 12 Mar 2026 09:19:33 +0800 (CST) From: Jiakai Xu To: kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-riscv@lists.infradead.org Cc: Albert Ou , Alexandre Ghiti , Andrew Jones , Anup Patel , Atish Patra , Palmer Dabbelt , Paolo Bonzini , Paul Walmsley , Shuah Khan , Jiakai Xu , Jiakai Xu , Andrew Jones Subject: [PATCH v4 1/2] RISC-V: KVM: Fix array out-of-bounds in pmu_ctr_read() and pmu_fw_ctr_read_hi() Date: Thu, 12 Mar 2026 01:19:30 +0000 Message-Id: <20260312011931.1352239-2-xujiakai2025@iscas.ac.cn> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260312011931.1352239-1-xujiakai2025@iscas.ac.cn> References: <20260312011931.1352239-1-xujiakai2025@iscas.ac.cn> 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: zQCowAAntwqkFLJpB6U4Cg--.65391S3 X-Coremail-Antispam: 1UD129KBjvJXoWxCF1fCFW8Xw1rtF4kZw13Arb_yoW5Ww18pr 47Kw1Yq395trs2vw1Yyw1Duw4Uta1kKw4DGrW7WF18Ar13Wry3JFyqg3sIvF43AF4Fqa4x tw1Iq3WxCFy5Xa7anT9S1TB71UUUUjDqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUL0b7Iv0xC_Kw4lb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI 8067AKxVWUGwA2048vs2IY020Ec7CjxVAFwI0_Gr0_Xr1l8cAvFVAK0II2c7xJM28CjxkF 64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4x0Y4vE2Ix0cI8IcV CY1x0267AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280 aVCY1x0267AKxVWxJr0_GcWln4kS14v26r126r1DM2vYz4IE04k24VAvwVAKI4IrM2AIxV AIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE 14v26r126r1DMcIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2 IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7M4IIrI8v6xkF7I0E8cxan2IY04v7 MxkF7I0En4kS14v26r4a6rW5MxkIecxEwVAFwVWkMxAIw28IcxkI7VAKI48JMxC20s026x CaFVCjc4AY6r1j6r4UMxCIbckI1I0E14v26r126r1DMI8I3I0E5I8CrVAFwI0_Jr0_Jr4l x2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZVWrXwCIc40Y0x0EwIxGrw CI42IY6xIIjxv20xvE14v26r4j6ryUMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI 42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z2 80aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IU8Dl1PUUUUU== X-CM-SenderInfo: 50xmxthndljiysv6x2xfdvhtffof0/1tbiDAcECWmx5uuPwQAAsd Content-Type: text/plain; charset="utf-8" When a guest invokes SBI_EXT_PMU_COUNTER_FW_READ or SBI_EXT_PMU_COUNTER_FW_READ_HI on a firmware counter that has not been configured via SBI_EXT_PMU_COUNTER_CFG_MATCH, the pmc->event_idx remains SBI_PMU_EVENT_IDX_INVALID (0xFFFFFFFF). get_event_code() extracts the lower 16 bits, yielding 0xFFFF (65535), which is then used to index into kvpmu->fw_event[]. Since fw_event is only RISCV_KVM_MAX_FW_CTRS (32) entries, this triggers an array-index-out-of-bounds: UBSAN: array-index-out-of-bounds in arch/riscv/kvm/vcpu_pmu.c:255:37 index 65535 is out of range for type 'kvm_fw_event [32]' Add a check for the known unconfigured case (SBI_PMU_EVENT_IDX_INVALID) and a WARN_ONCE guard for any unexpected out-of-bounds event codes, returning -EINVAL in both cases. Fixes: badc386869e2c ("RISC-V: KVM: Support firmware events") Fixes: 08fb07d6dcf71 ("RISC-V: KVM: Support 64 bit firmware counters on RV3= 2") Signed-off-by: Jiakai Xu Signed-off-by: Jiakai Xu Reviewed-by: Andrew Jones --- V3 -> V4: - Fixed WARN_ONCE argument alignment. V2 -> V3: - Added check for SBI_PMU_EVENT_IDX_INVALID. - Added WARN_ONCE for unexpected out-of-bounds event codes. V1 -> V2: - Merged the fixes for pmu_ctr_read() and pmu_fw_ctr_read_hi() into a single commit. - Removed the pr_warn, simply returning -EINVAL instead. --- arch/riscv/kvm/vcpu_pmu.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c index e873430e596b..6dadd18e510d 100644 --- a/arch/riscv/kvm/vcpu_pmu.c +++ b/arch/riscv/kvm/vcpu_pmu.c @@ -226,7 +226,14 @@ static int pmu_fw_ctr_read_hi(struct kvm_vcpu *vcpu, u= nsigned long cidx, if (pmc->cinfo.type !=3D SBI_PMU_CTR_TYPE_FW) return -EINVAL; =20 + if (pmc->event_idx =3D=3D SBI_PMU_EVENT_IDX_INVALID) + return -EINVAL; + fevent_code =3D get_event_code(pmc->event_idx); + if (WARN_ONCE(fevent_code >=3D SBI_PMU_FW_MAX, + "Invalid firmware event code: %d\n", fevent_code)) + return -EINVAL; + pmc->counter_val =3D kvpmu->fw_event[fevent_code].value; =20 *out_val =3D pmc->counter_val >> 32; @@ -251,7 +258,14 @@ static int pmu_ctr_read(struct kvm_vcpu *vcpu, unsigne= d long cidx, pmc =3D &kvpmu->pmc[cidx]; =20 if (pmc->cinfo.type =3D=3D SBI_PMU_CTR_TYPE_FW) { + if (pmc->event_idx =3D=3D SBI_PMU_EVENT_IDX_INVALID) + return -EINVAL; + fevent_code =3D get_event_code(pmc->event_idx); + if (WARN_ONCE(fevent_code >=3D SBI_PMU_FW_MAX, + "Invalid firmware event code: %d\n", fevent_code)) + return -EINVAL; + pmc->counter_val =3D kvpmu->fw_event[fevent_code].value; } else if (pmc->perf_event) { pmc->counter_val +=3D perf_event_read_value(pmc->perf_event, &enabled, &= running); --=20 2.34.1