From: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> Fix code added in 8d84097f965 (commit-graph: expire commit-graph files, 2019-06-18) to check the return value of the stat() system call. Not doing so caused us to use uninitialized memory in the "Bloom generation is limited by --max-new-filters" test in t4216-log-bloom.sh: + rm -f trace.event + pwd + GIT_TRACE2_EVENT=[...]/t/trash directory.t4216-log-bloom/limits/trace.event git commit-graph write --reachable --split=replace --changed-paths --max-new-filters=2 ==24835== Syscall param utimensat(times[0].tv_sec) points to uninitialised byte(s) ==24835== at 0x499E65A: __utimensat64_helper (utimensat.c:34) ==24835== by 0x4999142: utime (utime.c:36) ==24835== by 0x552BE0: mark_commit_graphs (commit-graph.c:2213) ==24835== by 0x550822: write_commit_graph (commit-graph.c:2424) ==24835== by 0x54E3A0: write_commit_graph_reachable (commit-graph.c:1681) ==24835== by 0x4374BB: graph_write (commit-graph.c:269) ==24835== by 0x436F7D: cmd_commit_graph (commit-graph.c:326) ==24835== by 0x407B9A: run_builtin (git.c:465) ==24835== by 0x406651: handle_builtin (git.c:719) ==24835== by 0x407575: run_argv (git.c:786) ==24835== by 0x406410: cmd_main (git.c:917) ==24835== by 0x511F09: main (common-main.c:56) ==24835== Address 0x1ffeffde70 is on thread 1's stack ==24835== in frame #1, created by utime (utime.c:25) ==24835== Uninitialised value was created by a stack allocation ==24835== at 0x552B50: mark_commit_graphs (commit-graph.c:2201) ==24835== [...] error: last command exited with $?=126 not ok 137 - Bloom generation is limited by --max-new-filters This would happen as we stat'd the non-existing ".git/objects/info/commit-graph" file. Let's fix mark_commit_graphs() to check the stat()'s return value, and while we're at it fix another case added in the same commit to do the same. The caller in expire_commit_graphs() would have been less likely to run into this, as it's operating on files it just got from readdir(), but it could still happen due to a race with e.g. a concurrent "rm -rf" of the commit-graph files. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx> --- commit-graph.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/commit-graph.c b/commit-graph.c index 441b36016b..2b52818731 100644 --- a/commit-graph.c +++ b/commit-graph.c @@ -2206,7 +2206,8 @@ static void mark_commit_graphs(struct write_commit_graph_context *ctx) struct stat st; struct utimbuf updated_time; - stat(ctx->commit_graph_filenames_before[i], &st); + if (stat(ctx->commit_graph_filenames_before[i], &st) < 0) + continue; updated_time.actime = st.st_atime; updated_time.modtime = now; @@ -2247,7 +2248,8 @@ static void expire_commit_graphs(struct write_commit_graph_context *ctx) strbuf_setlen(&path, dirnamelen); strbuf_addstr(&path, de->d_name); - stat(path.buf, &st); + if (stat(path.buf, &st) < 0) + continue; if (st.st_mtime > expire_time) continue; -- 2.36.1-338-g1c7f76a54c
