replace snprintf with odb_pack_name()

In several places we write the name of the pack filename into a fixed-size buffer using snprintf(), but do not check the return value. As a result, a very long object directory could cause us to quietly truncate the pack filename (potentially leading to a corrupted repository, as a newly written packfile could be missing its .pack extension). We can use odb_pack_name() to do this with a strbuf (and shorten the code, as well). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Jeff King committed Mar 16, 2017 at 10:27 UTC ba47a3088f04ac3d2833bea56ee366be1054db8d
2 files changed +24 -31
builtin/index-pack.c
+11 -16
@@ -1386,7 +1386,7 @@ static void final(const char *final_pack_name, const char *curr_pack_name,
1386 unsigned char *sha1)
1387 {
1388 const char *report = "pack";
1389 - char name[PATH_MAX];
1389 + struct strbuf name = STRBUF_INIT;
1390 int err;
1391
1392 if (!from_stdin) {
@@ -1402,14 +1402,13 @@ static void final(const char *final_pack_name, const char *curr_pack_name,
1402 int keep_fd, keep_msg_len = strlen(keep_msg);
1403
1404 if (!keep_name)
1405 - snprintf(name, sizeof(name), "%s/pack/pack-%s.keep",
1406 - get_object_directory(), sha1_to_hex(sha1));
1405 + odb_pack_name(&name, sha1, "keep");
1406
1408 - keep_fd = odb_pack_keep(keep_name ? keep_name : name);
1407 + keep_fd = odb_pack_keep(keep_name ? keep_name : name.buf);
1408 if (keep_fd < 0) {
1409 if (errno != EEXIST)
1410 die_errno(_("cannot write keep file '%s'"),
1412 - keep_name ? keep_name : name);
1411 + keep_name ? keep_name : name.buf);
1412 } else {
1413 if (keep_msg_len > 0) {
1414 write_or_die(keep_fd, keep_msg, keep_msg_len);
@@ -1417,28 +1416,22 @@ static void final(const char *final_pack_name, const char *curr_pack_name,
1416 }
1417 if (close(keep_fd) != 0)
1418 die_errno(_("cannot close written keep file '%s'"),
1420 - keep_name ? keep_name : name);
1419 + keep_name ? keep_name : name.buf);
1420 report = "keep";
1421 }
1422 }
1423
1424 if (final_pack_name != curr_pack_name) {
1426 - if (!final_pack_name) {
1427 - snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
1428 - get_object_directory(), sha1_to_hex(sha1));
1429 - final_pack_name = name;
1430 - }
1425 + if (!final_pack_name)
1426 + final_pack_name = odb_pack_name(&name, sha1, "pack");
1427 if (finalize_object_file(curr_pack_name, final_pack_name))
1428 die(_("cannot store pack file"));
1429 } else if (from_stdin)
1430 chmod(final_pack_name, 0444);
1431
1432 if (final_index_name != curr_index_name) {
1437 - if (!final_index_name) {
1438 - snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
1439 - get_object_directory(), sha1_to_hex(sha1));
1440 - final_index_name = name;
1441 - }
1433 + if (!final_index_name)
1434 + final_index_name = odb_pack_name(&name, sha1, "idx");
1435 if (finalize_object_file(curr_index_name, final_index_name))
1436 die(_("cannot store index file"));
1437 } else
@@ -1464,6 +1457,8 @@ static void final(const char *final_pack_name, const char *curr_pack_name,
1457 input_offset += err;
1458 }
1459 }
1460 +
1461 + strbuf_release(&name);
1462 }
1463
1464 static int git_index_pack_config(const char *k, const char *v, void *cb)
fast-import.c
+13 -15
@@ -940,43 +940,40 @@ static const char *create_index(void)
940
941 static char *keep_pack(const char *curr_index_name)
942 {
943 - static char name[PATH_MAX];
943 static const char *keep_msg = "fast-import";
944 + struct strbuf name = STRBUF_INIT;
945 int keep_fd;
946
947 - snprintf(name, sizeof(name), "%s/pack/pack-%s.keep",
948 - get_object_directory(), sha1_to_hex(pack_data->sha1));
949 - keep_fd = odb_pack_keep(name);
947 + odb_pack_name(&name, pack_data->sha1, "keep");
948 + keep_fd = odb_pack_keep(name.buf);
949 if (keep_fd < 0)
950 die_errno("cannot create keep file");
951 write_or_die(keep_fd, keep_msg, strlen(keep_msg));
952 if (close(keep_fd))
953 die_errno("failed to write keep file");
954
956 - snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
957 - get_object_directory(), sha1_to_hex(pack_data->sha1));
958 - if (finalize_object_file(pack_data->pack_name, name))
955 + odb_pack_name(&name, pack_data->sha1, "pack");
956 + if (finalize_object_file(pack_data->pack_name, name.buf))
957 die("cannot store pack file");
958
961 - snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
962 - get_object_directory(), sha1_to_hex(pack_data->sha1));
963 - if (finalize_object_file(curr_index_name, name))
959 + odb_pack_name(&name, pack_data->sha1, "idx");
960 + if (finalize_object_file(curr_index_name, name.buf))
961 die("cannot store index file");
962 free((void *)curr_index_name);
966 - return name;
963 + return strbuf_detach(&name, NULL);
964 }
965
966 static void unkeep_all_packs(void)
967 {
971 - static char name[PATH_MAX];
968 + struct strbuf name = STRBUF_INIT;
969 int k;
970
971 for (k = 0; k < pack_id; k++) {
972 struct packed_git *p = all_packs[k];
976 - snprintf(name, sizeof(name), "%s/pack/pack-%s.keep",
977 - get_object_directory(), sha1_to_hex(p->sha1));
978 - unlink_or_warn(name);
973 + odb_pack_name(&name, p->sha1, "keep");
974 + unlink_or_warn(name.buf);
975 }
976 + strbuf_release(&name);
977 }
978
979 static int loosen_small_pack(const struct packed_git *p)
@@ -1035,6 +1032,7 @@ static void end_packfile(void)
1032 die("core git rejected index %s", idx_name);
1033 all_packs[pack_id] = new_p;
1034 install_packed_git(new_p);
1035 + free(idx_name);
1036
1037 /* Print the boundary */
1038 if (pack_edges) {