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From: Ethan Tidmore <ethantidmore06@gmail.com>
To: anup@brainfault.org
Cc: atish.patra@linux.dev, pjw@kernel.org, palmer@dabbelt.com,
	aou@eecs.berkeley.edu, alex@ghiti.fr, ajones@ventanamicro.com,
	kvm@vger.kernel.org, kvm-riscv@lists.infradead.org,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	Ethan Tidmore <ethantidmore06@gmail.com>
Subject: [PATCH] RISC-V: KVM: Fix out-of-bounds by 1
Date: Sat, 28 Feb 2026 09:22:26 -0600	[thread overview]
Message-ID: <20260228152226.2116895-1-ethantidmore06@gmail.com> (raw)

The array kvpmu->pmc is defined as:

struct kvm_pmc pmc[RISCV_KVM_MAX_COUNTERS];

So, accessing it with index RISCV_KVM_MAX_COUNTERS would be
out-of-bounds by 1.

Change index check from > to >=.

Detected by Smatch:
arch/riscv/kvm/vcpu_pmu.c:528 kvm_riscv_vcpu_pmu_ctr_info() error:
buffer overflow 'kvpmu->pmc' 64 <= 64

Fixes: 8f0153ecd3bf1 ("RISC-V: KVM: Add skeleton support for perf")
Signed-off-by: Ethan Tidmore <ethantidmore06@gmail.com>
---
 arch/riscv/kvm/vcpu_pmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c
index 3a4d54aa96d8..51a12f90fb30 100644
--- a/arch/riscv/kvm/vcpu_pmu.c
+++ b/arch/riscv/kvm/vcpu_pmu.c
@@ -520,7 +520,7 @@ int kvm_riscv_vcpu_pmu_ctr_info(struct kvm_vcpu *vcpu, unsigned long cidx,
 {
 	struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
 
-	if (cidx > RISCV_KVM_MAX_COUNTERS || cidx == 1) {
+	if (cidx >= RISCV_KVM_MAX_COUNTERS || cidx == 1) {
 		retdata->err_val = SBI_ERR_INVALID_PARAM;
 		return 0;
 	}
-- 
2.53.0


-- 
kvm-riscv mailing list
kvm-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kvm-riscv

WARNING: multiple messages have this Message-ID (diff)
From: Ethan Tidmore <ethantidmore06@gmail.com>
To: anup@brainfault.org
Cc: atish.patra@linux.dev, pjw@kernel.org, palmer@dabbelt.com,
	aou@eecs.berkeley.edu, alex@ghiti.fr, ajones@ventanamicro.com,
	kvm@vger.kernel.org, kvm-riscv@lists.infradead.org,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	Ethan Tidmore <ethantidmore06@gmail.com>
Subject: [PATCH] RISC-V: KVM: Fix out-of-bounds by 1
Date: Sat, 28 Feb 2026 09:22:26 -0600	[thread overview]
Message-ID: <20260228152226.2116895-1-ethantidmore06@gmail.com> (raw)

The array kvpmu->pmc is defined as:

struct kvm_pmc pmc[RISCV_KVM_MAX_COUNTERS];

So, accessing it with index RISCV_KVM_MAX_COUNTERS would be
out-of-bounds by 1.

Change index check from > to >=.

Detected by Smatch:
arch/riscv/kvm/vcpu_pmu.c:528 kvm_riscv_vcpu_pmu_ctr_info() error:
buffer overflow 'kvpmu->pmc' 64 <= 64

Fixes: 8f0153ecd3bf1 ("RISC-V: KVM: Add skeleton support for perf")
Signed-off-by: Ethan Tidmore <ethantidmore06@gmail.com>
---
 arch/riscv/kvm/vcpu_pmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c
index 3a4d54aa96d8..51a12f90fb30 100644
--- a/arch/riscv/kvm/vcpu_pmu.c
+++ b/arch/riscv/kvm/vcpu_pmu.c
@@ -520,7 +520,7 @@ int kvm_riscv_vcpu_pmu_ctr_info(struct kvm_vcpu *vcpu, unsigned long cidx,
 {
 	struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
 
-	if (cidx > RISCV_KVM_MAX_COUNTERS || cidx == 1) {
+	if (cidx >= RISCV_KVM_MAX_COUNTERS || cidx == 1) {
 		retdata->err_val = SBI_ERR_INVALID_PARAM;
 		return 0;
 	}
-- 
2.53.0


WARNING: multiple messages have this Message-ID (diff)
From: Ethan Tidmore <ethantidmore06@gmail.com>
To: anup@brainfault.org
Cc: atish.patra@linux.dev, pjw@kernel.org, palmer@dabbelt.com,
	aou@eecs.berkeley.edu, alex@ghiti.fr, ajones@ventanamicro.com,
	kvm@vger.kernel.org, kvm-riscv@lists.infradead.org,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	Ethan Tidmore <ethantidmore06@gmail.com>
Subject: [PATCH] RISC-V: KVM: Fix out-of-bounds by 1
Date: Sat, 28 Feb 2026 09:22:26 -0600	[thread overview]
Message-ID: <20260228152226.2116895-1-ethantidmore06@gmail.com> (raw)

The array kvpmu->pmc is defined as:

struct kvm_pmc pmc[RISCV_KVM_MAX_COUNTERS];

So, accessing it with index RISCV_KVM_MAX_COUNTERS would be
out-of-bounds by 1.

Change index check from > to >=.

Detected by Smatch:
arch/riscv/kvm/vcpu_pmu.c:528 kvm_riscv_vcpu_pmu_ctr_info() error:
buffer overflow 'kvpmu->pmc' 64 <= 64

Fixes: 8f0153ecd3bf1 ("RISC-V: KVM: Add skeleton support for perf")
Signed-off-by: Ethan Tidmore <ethantidmore06@gmail.com>
---
 arch/riscv/kvm/vcpu_pmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c
index 3a4d54aa96d8..51a12f90fb30 100644
--- a/arch/riscv/kvm/vcpu_pmu.c
+++ b/arch/riscv/kvm/vcpu_pmu.c
@@ -520,7 +520,7 @@ int kvm_riscv_vcpu_pmu_ctr_info(struct kvm_vcpu *vcpu, unsigned long cidx,
 {
 	struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
 
-	if (cidx > RISCV_KVM_MAX_COUNTERS || cidx == 1) {
+	if (cidx >= RISCV_KVM_MAX_COUNTERS || cidx == 1) {
 		retdata->err_val = SBI_ERR_INVALID_PARAM;
 		return 0;
 	}
-- 
2.53.0


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

             reply	other threads:[~2026-02-28 15:22 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-28 15:22 Ethan Tidmore [this message]
2026-02-28 15:22 ` [PATCH] RISC-V: KVM: Fix out-of-bounds by 1 Ethan Tidmore
2026-02-28 15:22 ` Ethan Tidmore
2026-03-02 13:13 ` Anup Patel
2026-03-02 13:13   ` Anup Patel
2026-03-02 13:13   ` Anup Patel
2026-03-18 21:19 ` Ethan Tidmore
2026-03-18 21:19   ` Ethan Tidmore
2026-03-18 21:19   ` Ethan Tidmore
2026-03-24  6:07 ` patchwork-bot+linux-riscv
2026-03-24  6:07   ` patchwork-bot+linux-riscv
2026-03-24  6:07   ` patchwork-bot+linux-riscv

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