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commit-graph.c: prevent overflow in write_commit_graph_file()

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When writing a commit-graph, we use the chunk-format API to write out
each individual chunk of the commit-graph. Each chunk of the
commit-graph is tracked via a call to `add_chunk()`, along with the
expected size of that chunk.

Similar to an earlier commit which handled the identical issue in the
MIDX machinery, guard against overflow when dealing with a commit-graph
with a large number of entries to avoid corrupting the contents of the
commit-graph itself.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Taylor Blau
2023-07-12 19:37:54 -04:00
committed by Junio C Hamano
parent 0948c50176
commit 48f3f8cf37
1 changed files with 10 additions and 10 deletions
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20
commit-graph.c
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@ -1953,35 +1953,35 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
add_chunk(cf, GRAPH_CHUNKID_OIDFANOUT, GRAPH_FANOUT_SIZE, add_chunk(cf, GRAPH_CHUNKID_OIDFANOUT, GRAPH_FANOUT_SIZE,
write_graph_chunk_fanout); write_graph_chunk_fanout);
add_chunk(cf, GRAPH_CHUNKID_OIDLOOKUP, hashsz * ctx->commits.nr, add_chunk(cf, GRAPH_CHUNKID_OIDLOOKUP, st_mult(hashsz, ctx->commits.nr),
write_graph_chunk_oids); write_graph_chunk_oids);
add_chunk(cf, GRAPH_CHUNKID_DATA, (hashsz + 16) * ctx->commits.nr, add_chunk(cf, GRAPH_CHUNKID_DATA, st_mult(hashsz + 16, ctx->commits.nr),
write_graph_chunk_data); write_graph_chunk_data);
if (ctx->write_generation_data) if (ctx->write_generation_data)
add_chunk(cf, GRAPH_CHUNKID_GENERATION_DATA, add_chunk(cf, GRAPH_CHUNKID_GENERATION_DATA,
sizeof(uint32_t) * ctx->commits.nr, st_mult(sizeof(uint32_t), ctx->commits.nr),
write_graph_chunk_generation_data); write_graph_chunk_generation_data);
if (ctx->num_generation_data_overflows) if (ctx->num_generation_data_overflows)
add_chunk(cf, GRAPH_CHUNKID_GENERATION_DATA_OVERFLOW, add_chunk(cf, GRAPH_CHUNKID_GENERATION_DATA_OVERFLOW,
sizeof(timestamp_t) * ctx->num_generation_data_overflows, st_mult(sizeof(timestamp_t), ctx->num_generation_data_overflows),
write_graph_chunk_generation_data_overflow); write_graph_chunk_generation_data_overflow);
if (ctx->num_extra_edges) if (ctx->num_extra_edges)
add_chunk(cf, GRAPH_CHUNKID_EXTRAEDGES, add_chunk(cf, GRAPH_CHUNKID_EXTRAEDGES,
4 * ctx->num_extra_edges, st_mult(4, ctx->num_extra_edges),
write_graph_chunk_extra_edges); write_graph_chunk_extra_edges);
if (ctx->changed_paths) { if (ctx->changed_paths) {
add_chunk(cf, GRAPH_CHUNKID_BLOOMINDEXES, add_chunk(cf, GRAPH_CHUNKID_BLOOMINDEXES,
sizeof(uint32_t) * ctx->commits.nr, st_mult(sizeof(uint32_t), ctx->commits.nr),
write_graph_chunk_bloom_indexes); write_graph_chunk_bloom_indexes);
add_chunk(cf, GRAPH_CHUNKID_BLOOMDATA, add_chunk(cf, GRAPH_CHUNKID_BLOOMDATA,
sizeof(uint32_t) * 3 st_add(sizeof(uint32_t) * 3,
+ ctx->total_bloom_filter_data_size, ctx->total_bloom_filter_data_size),
write_graph_chunk_bloom_data); write_graph_chunk_bloom_data);
} }
if (ctx->num_commit_graphs_after > 1) if (ctx->num_commit_graphs_after > 1)
add_chunk(cf, GRAPH_CHUNKID_BASE, add_chunk(cf, GRAPH_CHUNKID_BASE,
hashsz * (ctx->num_commit_graphs_after - 1), st_mult(hashsz, ctx->num_commit_graphs_after - 1),
write_graph_chunk_base); write_graph_chunk_base);
hashwrite_be32(f, GRAPH_SIGNATURE); hashwrite_be32(f, GRAPH_SIGNATURE);
@ -1999,7 +1999,7 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
get_num_chunks(cf)); get_num_chunks(cf));
ctx->progress = start_delayed_progress( ctx->progress = start_delayed_progress(
progress_title.buf, progress_title.buf,
get_num_chunks(cf) * ctx->commits.nr); st_mult(get_num_chunks(cf), ctx->commits.nr));
} }
write_chunkfile(cf, ctx); write_chunkfile(cf, ctx);