google / alioth / 36253299065

38%

Build Type

push

github

Committed by Lencerf

Commit Message

fix(cli): reject qcow2 images with out-of-range cluster_bits

`alioth img convert` used `cluster_bits` from the qcow2 header without
validation, so a crafted image could make it panic: shift overflow for
values >= 64, capacity overflow for 63, and subtraction underflow in
`Qcow2CmprDesc::offset_size()` for values < 8.

Reject values outside [9, 21] right after reading the header. The lower
bound is required by the qcow2 specification. The specification sets no
upper bound, but 2 MiB is QEMU's implementation limit, and it also
bounds the cluster-sized buffers allocated during conversion.

Fixes: c56fa53e54b3 ("feat(cli): add a new command to convert Qcow2 images")
Closes: #498
Assisted-by: Antigravity:Claude-Opus-5
Signed-off-by: Changyuan Lyu <changyuanl@google.com>

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