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KVM: s390: Harden copying of userspace-array against overflow

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guestdbg.c utilizes memdup_user() to copy a userspace array. This,
currently, does not check for an overflow.

Use the new wrapper memdup_array_user() to copy the array more safely.

Note, KVM explicitly checks the number of entries before duplicating the
array, i.e. adding the overflow check should be a glorified nop.

Suggested-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Link: https://lore.kernel.org/r/20231102181526.43279-3-pstanner@redhat.com
[sean: call out that KVM pre-checks the number of entries]
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Philipp Stanner 2023-11-02 19:15:25 +01:00 committed by Sean Christopherson
parent 573cc0e5cf
commit 8c4976772d
1 changed files with 2 additions and 2 deletions
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4
arch/s390/kvm/guestdbg.c
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@ -213,8 +213,8 @@ int kvm_s390_import_bp_data(struct kvm_vcpu *vcpu,
else if (dbg->arch.nr_hw_bp > MAX_BP_COUNT)
return -EINVAL;
bp_data = memdup_user(dbg->arch.hw_bp,
sizeof(*bp_data) * dbg->arch.nr_hw_bp);
bp_data = memdup_array_user(dbg->arch.hw_bp, dbg->arch.nr_hw_bp,
sizeof(*bp_data));
if (IS_ERR(bp_data))
return PTR_ERR(bp_data);