reftable/stack: fix zero-sized allocation when there are no readers
Similar as the preceding commit, we may try to do a zero-sized allocation when reloading a reftable stack that ain't got any tables. It is implementation-defined whether malloc(3p) returns a NULL pointer in that case or a zero-sized object. In case it does return a NULL pointer though it causes us to think we have run into an out-of-memory situation, and thus we return an error. Fix this by only allocating arrays when they have at least one entry. Reported-by: Randall S. Becker <rsbecker@nexbridge.com> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Patrick Steinhardt committed
Dec 22, 2024 at 08:24 UTC
2d3cb4b4b5401e2fd5a40600277f424032fc72f0
1 file changed
+14
-10
reftable/stack.c
+14
-10
@@ -254,9 +254,9 @@ static int reftable_stack_reload_once(struct reftable_stack *st,
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int reuse_open)
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{
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size_t cur_len = !st->merged ? 0 : st->merged->readers_len;
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- struct reftable_reader **cur;
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+ struct reftable_reader **cur = NULL;
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struct reftable_reader **reused = NULL;
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- struct reftable_reader **new_readers;
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+ struct reftable_reader **new_readers = NULL;
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size_t reused_len = 0, reused_alloc = 0, names_len;
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size_t new_readers_len = 0;
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struct reftable_merged_table *new_merged = NULL;
@@ -264,18 +264,22 @@ static int reftable_stack_reload_once(struct reftable_stack *st,
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int err = 0;
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size_t i;
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- cur = stack_copy_readers(st, cur_len);
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- if (!cur) {
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- err = REFTABLE_OUT_OF_MEMORY_ERROR;
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- goto done;
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+ if (cur_len) {
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+ cur = stack_copy_readers(st, cur_len);
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+ if (!cur) {
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+ err = REFTABLE_OUT_OF_MEMORY_ERROR;
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+ goto done;
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+ }
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}
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names_len = names_length(names);
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- new_readers = reftable_calloc(names_len, sizeof(*new_readers));
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- if (!new_readers) {
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- err = REFTABLE_OUT_OF_MEMORY_ERROR;
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- goto done;
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+ if (names_len) {
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+ new_readers = reftable_calloc(names_len, sizeof(*new_readers));
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+ if (!new_readers) {
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+ err = REFTABLE_OUT_OF_MEMORY_ERROR;
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+ goto done;
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+ }
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}
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while (*names) {