The config_receive_{basis,skip,idmap}_count helpers wrote the
peer-controlled int through the Config member before range-checking it.
An over-cap basis_count therefore left config->basis_count huge while
config->basis_dirs was still NULL; config_receive()'s error path then
called config_delete(), whose basis loop dereferenced NULL and crashed
the daemon before authentication.
Read each count into a local, validate, and only then assign, leaving the
member untouched on failure. config_delete() also guards the basis loop
with the array pointer as defense in depth.
Add a regression test that feeds over-cap basis/idmap/skip counts and
asserts rejection without crashing, plus a direct config_delete() check
on the partial (count set, array NULL) state.
Address low-severity review findings on the X-macro config refactor:
1. The golden test only hashed config_send_wire_block(), so a
receive-side KIND that reads a different width/order could still
round-trip symmetrically. Add test_config_wire_golden_receive():
capture the same hash-pinned 633-byte frame and feed it through
config_receive(), asserting every field (config_wire_equal) plus the
derived use_delta/use_xattrs bits and representative bounded kinds.
Add test_config_wire_receive_bounds() for bounds the symmetric
round-trip cannot reach: an out-of-range BOOL (hand-built frame),
RAW_MAXALLOC zero, a malformed STR_MODULE, an over-cap
INT_IDMAPCOUNT, and an out-of-range INT_IDENTITY chown_uid.
2. golden_config_populate() set long runs of booleans to all-1, so an
adjacent swap within a run produced identical bytes. Alternate the
boolean values and make the fixture receiver-valid (chmod grammar
"u=rwx,go=rx" is the same 11 bytes; delta_max_file_size inside the
bound). Re-pin the golden: len stays 633, hash is now
9160991280011164139 (computed, not guessed).
3. Document in config.h and client_cli.c that the CLI option tables
remain hand-maintained and are deliberately not generated from the
wire-field X-macro (client-only fields, flag/alias/negation
semantics). No CLI-table rewrite.
PROTOCOL_VERSION stays "2.20.0"; src/shared/config.c is untouched and
the wire bytes are unchanged apart from the fixture's own new values.
test_config_wire_golden() serializes a fully-populated Config through
config_send_wire_block() and pins the exact frame to len=633 and FNV-1a
hash 6163263374908258816, captured from the pre-X-macro implementation.
Any field reorder, resize or codec change fails the test.
test_config_wire_roundtrip_all_fields() serializes/deserializes a defaults
Config and a fully-populated Config over a socketpair and compares every
serialized field. The comparison is itself generated from
CONFIG_WIRE_FIELDS (one CONFIG_CMP_<KIND> per table entry), so a new table
entry automatically extends coverage; it cannot fall out of sync. It
normalizes the receiver's NULL/"" canonicalization, the max_alloc server
clamp and the derived use_delta/use_xattrs bits.
Every Config field that crosses the wire was declared in up to six places
(struct member, config_set_defaults, send_*, receive_*, and the two CLI
option tables) and could drift silently. Add CONFIG_WIRE_FIELDS in
config.h: one ordered per-segment table where each serialized field is
declared once with its C type, default and wire codec (KIND).
config.h now expands the table to declare the struct members;
config_set_defaults() expands it to assign the defaults; and
config_send_wire_block()/config_receive() expand the per-segment lists to
emit/consume the frame. The per-segment function names, call order and
segment boundaries are preserved exactly.
Fields with genuinely custom logic keep dedicated helpers but are still
declared once in the table: the protocol-version handshake (HEADER), daemon
SCRAM auth (STR_REDACTED_AUTH), the daemon module name (STR_MODULE), the
repeated count+array blocks (BLOCK_SKIP_SUFFIXES/BLOCK_BASIS/BLOCK_IDMAP),
--copy-as presence/ids (COPY_AS_*), and the derived --delta / use_xattrs
bits (DERIVED_DELTA, BOOL_XATTR_DERIVE). The version field remains a
special header (validated before any other field is parsed) and is sent by
config_send_wire_block() explicitly.
No public field is renamed and PROTOCOL_VERSION stays "2.20.0". Because
the struct declaration order is no longer the wire order, the wire order is
now enforced solely by the table and by a byte-exact golden test
(follow-up commit). Add config_send_wire_block() so that test can hash the
frame body without the STATUS_OK handshake.
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