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A malformed qcow2 header with an invalid cluster_bits value could cause a panic due to a left-shift overflow when calculating the cluster size. This could be triggered by a crafted qcow2 image, leading to a denial of service. This commit fixes the issue by validating the cluster_bits field before it is used. The value is now checked to be within a valid range (9 to 30, inclusive) to prevent the overflow. If the value is out of range, the header parsing function now returns an error instead of panicking. A test case with a known malformed header has been added to ensure this vulnerability does not regress. Signed-off-by: Ming Lei <ming.lei@redhat.com>
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A malformed qcow2 header with an invalid cluster_bits value could cause a panic due to a left-shift overflow when calculating the cluster size. This could be triggered by a crafted qcow2 image, leading to a denial of service.
This commit fixes the issue by validating the cluster_bits field before it is used. The value is now checked to be within a valid range (9 to 30, inclusive) to prevent the overflow. If the value is out of range, the header parsing function now returns an error instead of panicking.
A test case with a known malformed header has been added to ensure this vulnerability does not regress.