[PATCH v2 3/4] reftable/stack: fix zero-sized allocation when there are no readers
- From
Patrick Steinhardt <ps@pks.im>
- Date
- Dec 22, 2024, 07:24 UTC
- Message-ID
- <20241222-b4-pks-reftable-oom-fix-without-readers-v2-3-19550090d15a@pks.im>
- In-Reply-To
- <20241222-b4-pks-reftable-oom-fix-without-readers-v2-0-19550090d15a@pks.im>
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> --- reftable/stack.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-)
diff --git a/reftable/stack.c b/reftable/stack.c index 6ca21965d8e1135d986043113d465abd14cd532c..634f0c54251b3581ca73250aca9f653f4645a569 100644 --- a/reftable/stack.c +++ b/reftable/stack.c @@ -270,9 +270,9 @@ static int reftable_stack_reload_once(struct reftable_stack *st, int reuse_open) { size_t cur_len = !st->merged ? 0 : st->merged->readers_len; - struct reftable_reader **cur; + struct reftable_reader **cur = NULL; struct reftable_reader **reused = NULL; - struct reftable_reader **new_readers; + struct reftable_reader **new_readers = NULL; size_t reused_len = 0, reused_alloc = 0, names_len; size_t new_readers_len = 0; struct reftable_merged_table *new_merged = NULL; @@ -280,18 +280,22 @@ static int reftable_stack_reload_once(struct reftable_stack *st, int err = 0; size_t i; - cur = stack_copy_readers(st, cur_len); - if (!cur) { - err = REFTABLE_OUT_OF_MEMORY_ERROR; - goto done; + if (cur_len) { + cur = stack_copy_readers(st, cur_len); + if (!cur) { + err = REFTABLE_OUT_OF_MEMORY_ERROR; + goto done; + } } names_len = names_length(names); - new_readers = reftable_calloc(names_len, sizeof(*new_readers)); - if (!new_readers) { - err = REFTABLE_OUT_OF_MEMORY_ERROR; - goto done; + if (names_len) { + new_readers = reftable_calloc(names_len, sizeof(*new_readers)); + if (!new_readers) { + err = REFTABLE_OUT_OF_MEMORY_ERROR; + goto done; + } } while (*names) {
-- 2.48.0.rc0.184.g0fc57dec57.dirty