Commit b86bc285 authored by David Rientjes's avatar David Rientjes Committed by Paolo Bonzini

KVM: SVM: prevent DBG_DECRYPT and DBG_ENCRYPT overflow

This ensures that the address and length provided to DBG_DECRYPT and
DBG_ENCRYPT do not cause an overflow.

At the same time, pass the actual number of pages pinned in memory to
sev_unpin_memory() as a cleanup.
Reported-by: default avatarCfir Cohen <cfir@google.com>
Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent ede885ec
...@@ -6799,7 +6799,8 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec) ...@@ -6799,7 +6799,8 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec)
struct page **src_p, **dst_p; struct page **src_p, **dst_p;
struct kvm_sev_dbg debug; struct kvm_sev_dbg debug;
unsigned long n; unsigned long n;
int ret, size; unsigned int size;
int ret;
if (!sev_guest(kvm)) if (!sev_guest(kvm))
return -ENOTTY; return -ENOTTY;
...@@ -6807,6 +6808,11 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec) ...@@ -6807,6 +6808,11 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec)
if (copy_from_user(&debug, (void __user *)(uintptr_t)argp->data, sizeof(debug))) if (copy_from_user(&debug, (void __user *)(uintptr_t)argp->data, sizeof(debug)))
return -EFAULT; return -EFAULT;
if (!debug.len || debug.src_uaddr + debug.len < debug.src_uaddr)
return -EINVAL;
if (!debug.dst_uaddr)
return -EINVAL;
vaddr = debug.src_uaddr; vaddr = debug.src_uaddr;
size = debug.len; size = debug.len;
vaddr_end = vaddr + size; vaddr_end = vaddr + size;
...@@ -6857,8 +6863,8 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec) ...@@ -6857,8 +6863,8 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec)
dst_vaddr, dst_vaddr,
len, &argp->error); len, &argp->error);
sev_unpin_memory(kvm, src_p, 1); sev_unpin_memory(kvm, src_p, n);
sev_unpin_memory(kvm, dst_p, 1); sev_unpin_memory(kvm, dst_p, n);
if (ret) if (ret)
goto err; goto err;
......
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