erofs-freebsd-out-tree/tests/TC137-xattr-declared-image-bounds.md

Test Case: Xattr declared-image bounds

Test ID: TC137-xattr-declared-image-bounds Fixtures: basic.erofs, bad-shared-declared-bounds.erofs, bad-prefix-declared-bounds.erofs

Objective

Ensure shared and prefix reads are bounded by superblock blocks, even when the provider contains a valid-looking appended sentinel. Require manifest provider/declared sizes, sentinel offsets, redirected ID/start, and hashes.

Manual steps

Run three independent cycles:

# basic.erofs control
getextattr -qq -x user shared_key /mnt/repo22-g4/shared-a
getextattr -qq -x user local /mnt/repo22-g4/shared-a

# bad-shared-declared-bounds.erofs
stat -f 'size=%z' /mnt/repo22-g4/shared-a
getextattr -qq -x user local /mnt/repo22-g4/shared-a
truss -o /tmp/tc137-shared.truss getextattr -qq user shared_key \
  /mnt/repo22-g4/shared-a
grep extattr_get_file /tmp/tc137-shared.truss

# bad-prefix-declared-bounds.erofs
truss -f -o /tmp/tc137-prefix.truss mount -t erofs -o ro \
  /dev/${unit} /mnt/repo22-g4
grep nmount /tmp/tc137-prefix.truss

Expected results

Control passes. The shared sentinel get and prefix mount return EINTEGRITY (97); normal data and local remain readable. Sentinel bytes never appear.