From: Patrick Steinhardt Date: Sun, 22 Dec 2024 07:24:30 +0000 (+0100) Subject: reftable/stack: fix zero-sized allocation when there are no readers X-Git-Tag: v2.48.0-rc1~23^2~1 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2d3cb4b4b5401e2fd5a40600277f424032fc72f0;p=thirdparty%2Fgit.git 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 Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- diff --git a/reftable/stack.c b/reftable/stack.c index ae274cd51c..f51d3ec9d9 100644 --- a/reftable/stack.c +++ b/reftable/stack.c @@ -254,9 +254,9 @@ 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; @@ -264,18 +264,22 @@ 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) {