From: Jan Kiszka <jan.kiszka@web.de>
To: Anthony Liguori <aliguori@us.ibm.com>
Cc: qemu-devel <qemu-devel@nongnu.org>, Avi Kivity <avi@redhat.com>
Subject: [Qemu-devel] [PATCH] kvm: Work around borken MSR_GET_INDEX_LIST
Date: Thu, 02 Jul 2009 22:04:48 +0200 [thread overview]
Message-ID: <4A4D12E0.9070909@web.de> (raw)
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Allocate enough memory for KVM_GET_MSR_INDEX_LIST as older kernels shot
far beyond their limits, corrupting user space memory.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
target-i386/kvm.c | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 4a3f598..cab9fcc 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -239,8 +239,11 @@ static int kvm_has_msr_star(CPUState *env)
if (ret < 0)
return 0;
- kvm_msr_list = qemu_mallocz(sizeof(msr_list) +
- msr_list.nmsrs * sizeof(msr_list.indices[0]));
+ /* Old kernel modules had a bug and could write beyond the provided
+ memory. Allocate at least a safe amount of 1K. */
+ kvm_msr_list = qemu_mallocz(MAX(1024, sizeof(msr_list) +
+ msr_list.nmsrs *
+ sizeof(msr_list.indices[0])));
kvm_msr_list->nmsrs = msr_list.nmsrs;
ret = kvm_ioctl(env->kvm_state, KVM_GET_MSR_INDEX_LIST, kvm_msr_list);
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reply other threads:[~2009-07-02 20:05 UTC|newest]
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