[PATCH] RISC-V: KVM: Fix sdata leak and stale snapshot_addr in snapshot_set_shmem
Zongmin Zhou <[email protected]>
| Newsgroups | org.infradead.lists.linux-riscv,org.infradead.lists.kvm-riscv,org.kernel.vger.kvm,org.kernel.vger.linux-kernel,org.kernel.vger.stable |
|---|---|
| Message-ID | <[email protected]> |
From: Zongmin Zhou <[email protected]> A guest may call SBI_PMU_SNAPSHOT_SET_SHMEM repeatedly. Each call overwrites kvpmu->sdata without freeing the old buffer (memory leak), and if a later kvm_vcpu_write_guest() fails, the error path frees sdata but leaves snapshot_addr stale. A subsequent SBI_PMU_COUNTER_START then passes the INVALID_GPA check and crashes the host with a NULL buffer in kvm_vcpu_read_guest(). Fix this by clearing the previously installed snapshot area before installing a new one, which keeps sdata and snapshot_addr consistent. The SBI spec suggests a single invocation but defines no error code for repeated calls, so KVM must tolerate them. Fixes: c2f41ddbcdd756 ("RISC-V: KVM: Implement SBI PMU Snapshot feature") Cc: [email protected] Signed-off-by: Zongmin Zhou <[email protected]> --- arch/riscv/kvm/vcpu_pmu.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c index 752f1014d633e7d67f69c27b72088ed560c187ac..14f73490f12cbc5a8547859f0d1bb1170d89403b 100644 --- a/arch/riscv/kvm/vcpu_pmu.c +++ b/arch/riscv/kvm/vcpu_pmu.c @@ -454,6 +454,14 @@ int kvm_riscv_vcpu_pmu_snapshot_set_shmem(struct kvm_vcpu *vcpu, unsigned long s } } + /* + * Clear any previously installed snapshot area to avoid leaking + * the old sdata and to keep sdata/snapshot_addr consistent if + * the re-install fails below. + */ + if (kvpmu->snapshot_addr != INVALID_GPA) + kvm_pmu_clear_snapshot_area(vcpu); + kvpmu->sdata = kzalloc(snapshot_area_size, GFP_ATOMIC | __GFP_ACCOUNT); if (!kvpmu->sdata) { sbiret = SBI_ERR_FAILURE; -- 2.34.1 No virus found Checked by Hillstone Network AntiVirus _______________________________________________ linux-riscv mailing list [email protected] http://lists.infradead.org/mailman/listinfo/linux-riscv