57 lines
1.7 KiB
Markdown
57 lines
1.7 KiB
Markdown
# Test Case: Invalid Superblock Magic
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**Test ID**: TC112-invalid-superblock
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**Category**: Error Handling
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**Priority**: Critical
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## Objective
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Verify rejection of an invalid EROFS magic at the real field while provider
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length and all suffix bytes covered by repo22's production checksum verifier
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remain unchanged.
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## Fixture Qualification
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```sh
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work=$(mktemp -d /tmp/repo22-tc112.XXXXXX)
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tests/prepare_error_fixtures.sh "$work/fixtures"
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od -An -tx4 -j 1024 -N 4 "$work/fixtures/bad-magic.erofs"
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python3 tests/erofs_fixture.py inspect "$work/fixtures/bad-magic.erofs"
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grep '^bad-magic ' "$work/fixtures/fixture-evidence.txt"
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wc -c "$work/fixtures/valid-plain.erofs" \
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"$work/fixtures/bad-magic.erofs"
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sha256 -q "$work/fixtures/bad-magic.erofs"
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```
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The mutator asserts magic `0xe0f5e1e2` at byte 1024 and replaces it with
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`0x21444142`. It intentionally leaves the stored checksum unchanged. The
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canonical checksum over the changed magic is invalid, but the production
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fixed-magic suffix calculation over `[1032,4096)` remains valid because no
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suffix byte changed. Magic validation occurs first.
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## FreeBSD Procedure
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```sh
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mkdir "$work/mnt"
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unit=$(mdconfig -a -t vnode -f "$work/fixtures/bad-magic.erofs")
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set +e
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mount -t erofs -o ro "/dev/$unit" "$work/mnt" \
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>"$work/mount.out" 2>"$work/mount.err"
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status=$?
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set -e
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test "$status" -ne 0
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set +e
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truss -o "$work/mount.truss" mount -t erofs -o ro "/dev/$unit" \
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"$work/mnt" >/dev/null 2>&1
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set -e
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grep -E 'nmount.*ERR#22' "$work/mount.truss"
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! mount -p | awk -v path="$work/mnt" '$2 == path { found=1 }
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END { exit found ? 0 : 1 }'
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mdconfig -d -u "${unit#md}"
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```
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## Expected Results
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Mount returns errno 22 (`EINVAL`) before root vnode creation. No panic, mount,
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or md consumer remains.
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