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author | 2018-02-23 12:36:50 -0600 | |
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committer | 2018-02-24 02:24:12 +0100 | |
commit | 3e233385ef4a217a2812115ed84d4be36eb16817 (patch) | |
tree | 68739747947735b581d92137b65d148227dec70a /arch/x86 | |
parent | include: psp-sev: Capitalize invalid length enum (diff) | |
download | linux-3e233385ef4a217a2812115ed84d4be36eb16817.tar.gz linux-3e233385ef4a217a2812115ed84d4be36eb16817.tar.bz2 linux-3e233385ef4a217a2812115ed84d4be36eb16817.zip |
KVM: SVM: no need to call access_ok() in LAUNCH_MEASURE command
Using the access_ok() to validate the input before issuing the SEV
command does not buy us anything in this case. If userland is
giving us a garbage pointer then copy_to_user() will catch it when we try
to return the measurement.
Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Fixes: 0d0736f76347 (KVM: SVM: Add support for KVM_SEV_LAUNCH_MEASURE ...)
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-kernel@vger.kernel.org
Cc: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/kvm/svm.c | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index b3e488a74828..ca69d53d7e6d 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -6236,16 +6236,18 @@ e_free: static int sev_launch_measure(struct kvm *kvm, struct kvm_sev_cmd *argp) { + void __user *measure = (void __user *)(uintptr_t)argp->data; struct kvm_sev_info *sev = &kvm->arch.sev_info; struct sev_data_launch_measure *data; struct kvm_sev_launch_measure params; + void __user *p = NULL; void *blob = NULL; int ret; if (!sev_guest(kvm)) return -ENOTTY; - if (copy_from_user(¶ms, (void __user *)(uintptr_t)argp->data, sizeof(params))) + if (copy_from_user(¶ms, measure, sizeof(params))) return -EFAULT; data = kzalloc(sizeof(*data), GFP_KERNEL); @@ -6256,17 +6258,13 @@ static int sev_launch_measure(struct kvm *kvm, struct kvm_sev_cmd *argp) if (!params.len) goto cmd; - if (params.uaddr) { + p = (void __user *)(uintptr_t)params.uaddr; + if (p) { if (params.len > SEV_FW_BLOB_MAX_SIZE) { ret = -EINVAL; goto e_free; } - if (!access_ok(VERIFY_WRITE, params.uaddr, params.len)) { - ret = -EFAULT; - goto e_free; - } - ret = -ENOMEM; blob = kmalloc(params.len, GFP_KERNEL); if (!blob) @@ -6290,13 +6288,13 @@ cmd: goto e_free_blob; if (blob) { - if (copy_to_user((void __user *)(uintptr_t)params.uaddr, blob, params.len)) + if (copy_to_user(p, blob, params.len)) ret = -EFAULT; } done: params.len = data->len; - if (copy_to_user((void __user *)(uintptr_t)argp->data, ¶ms, sizeof(params))) + if (copy_to_user(measure, ¶ms, sizeof(params))) ret = -EFAULT; e_free_blob: kfree(blob); |