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commit-graph: verify corrupt OID fanout and lookup

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In the commit-graph file, the OID fanout chunk provides an index into
the OID lookup. The 'verify' subcommand should find incorrect values
in the fanout.

Similarly, the 'verify' subcommand should find out-of-order values in
the OID lookup.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Derrick Stolee 2018-06-27 09:24:35 -04:00 committed by Junio C Hamano
parent 2bd0365f37
commit 9bda846789
2 changed files with 58 additions and 0 deletions
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36
commit-graph.c
View File

@ -843,6 +843,9 @@ static void graph_report(const char *fmt, ...)
int verify_commit_graph(struct repository *r, struct commit_graph *g)
{
uint32_t i, cur_fanout_pos = 0;
struct object_id prev_oid, cur_oid;
if (!g) {
graph_report("no commit-graph file loaded");
return 1;
@ -857,5 +860,38 @@ int verify_commit_graph(struct repository *r, struct commit_graph *g)
if (!g->chunk_commit_data)
graph_report("commit-graph is missing the Commit Data chunk");
if (verify_commit_graph_error)
return verify_commit_graph_error;
for (i = 0; i < g->num_commits; i++) {
hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
graph_report("commit-graph has incorrect OID order: %s then %s",
oid_to_hex(&prev_oid),
oid_to_hex(&cur_oid));
oidcpy(&prev_oid, &cur_oid);
while (cur_oid.hash[0] > cur_fanout_pos) {
uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
if (i != fanout_value)
graph_report("commit-graph has incorrect fanout value: fanout[%d] = %u != %u",
cur_fanout_pos, fanout_value, i);
cur_fanout_pos++;
}
}
while (cur_fanout_pos < 256) {
uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
if (g->num_commits != fanout_value)
graph_report("commit-graph has incorrect fanout value: fanout[%d] = %u != %u",
cur_fanout_pos, fanout_value, i);
cur_fanout_pos++;
}
return verify_commit_graph_error;
}

22
t/t5318-commit-graph.sh
View File

@ -247,6 +247,7 @@ test_expect_success 'git commit-graph verify' '
git commit-graph verify >output
'
HASH_LEN=20
GRAPH_BYTE_VERSION=4
GRAPH_BYTE_HASH=5
GRAPH_BYTE_CHUNK_COUNT=6
@ -258,6 +259,12 @@ GRAPH_BYTE_OID_LOOKUP_ID=$(($GRAPH_CHUNK_LOOKUP_OFFSET + \
1 * $GRAPH_CHUNK_LOOKUP_WIDTH))
GRAPH_BYTE_COMMIT_DATA_ID=$(($GRAPH_CHUNK_LOOKUP_OFFSET + \
2 * $GRAPH_CHUNK_LOOKUP_WIDTH))
GRAPH_FANOUT_OFFSET=$(($GRAPH_CHUNK_LOOKUP_OFFSET + \
$GRAPH_CHUNK_LOOKUP_WIDTH * $GRAPH_CHUNK_LOOKUP_ROWS))
GRAPH_BYTE_FANOUT1=$(($GRAPH_FANOUT_OFFSET + 4 * 4))
GRAPH_BYTE_FANOUT2=$(($GRAPH_FANOUT_OFFSET + 4 * 255))
GRAPH_OID_LOOKUP_OFFSET=$(($GRAPH_FANOUT_OFFSET + 4 * 256))
GRAPH_BYTE_OID_LOOKUP_ORDER=$(($GRAPH_OID_LOOKUP_OFFSET + $HASH_LEN * 8))
# usage: corrupt_graph_and_verify <position> <data> <string>
# Manipulates the commit-graph file at the position
@ -312,4 +319,19 @@ test_expect_success 'detect missing commit data chunk' '
"missing the Commit Data chunk"
'
test_expect_success 'detect incorrect fanout' '
corrupt_graph_and_verify $GRAPH_BYTE_FANOUT1 "\01" \
"fanout value"
'
test_expect_success 'detect incorrect fanout final value' '
corrupt_graph_and_verify $GRAPH_BYTE_FANOUT2 "\01" \
"fanout value"
'
test_expect_success 'detect incorrect OID order' '
corrupt_graph_and_verify $GRAPH_BYTE_OID_LOOKUP_ORDER "\01" \
"incorrect OID order"
'
test_done