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(unknown [210.73.43.101]) by APP-03 (Coremail) with SMTP id rQCowAC30Ndvsq9p08A4Cg--.55585S3; Tue, 10 Mar 2026 13:56:00 +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 Subject: [PATCH v3 1/2] RISC-V: KVM: Fix array out-of-bounds in pmu_ctr_read() and pmu_fw_ctr_read_hi() Date: Tue, 10 Mar 2026 05:55:56 +0000 Message-Id: <20260310055557.835531-2-xujiakai2025@iscas.ac.cn> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260310055557.835531-1-xujiakai2025@iscas.ac.cn> References: <20260310055557.835531-1-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: rQCowAC30Ndvsq9p08A4Cg--.55585S3 X-Coremail-Antispam: 1UD129KBjvJXoWxCF1fCFW8Xw1rtF4kZw13Arb_yoW5Xw1fpr 47Kwn0q395trZ2vw1Yyw1Duw4Uta1kK398WrW7WF18Aw13Wry3JFyDW3sIqF43AF4Fqa4x tw1Ig3WxCFy5Xa7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUHj14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jr4l82xGYIkIc2 x26xkF7I0E14v26r4j6ryUM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJw A2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAa c4AC62xK8xCEY4vEwIxC4wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzV Aqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUXVWUAwAv7VC2z280aVAFwI0_Gr0_Cr1lOx8S 6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxw ACI402YVCY1x02628vn2kIc2xKxwCY1x0262kKe7AKxVWUtVW8ZwCY02Avz4vE14v_GrWl 42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJV WUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5MIIYrxkI7VAK I48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F 4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY 6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfUj0edDUUUU X-CM-SenderInfo: 50xmxthndljiysv6x2xfdvhtffof0/1tbiBwkCCWmvo+0qZgAAsB 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 --- 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..c87a7b0037cf 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