Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> writes:
> But there's a few that aren't obviously allocations (this is a list done
> with grep and sparse, I didn't look at whether the values used are then
> all allocation-related):
>
> - builtin-blame.c:128 memset(o, 0, sizeof(*o));
This is harmless and in fact unnecessary clearing, immediately before
calling free(3).
> - diff-delta.c:250 memsize = sizeof(*index)
I haven't studied this codepath.
> - object-refs.c:23 size_t size = sizeof(*refs) + count*sizeof(struct object *);
Overallocation to have at least "count" pointers to "struct object".
> - object-refs.c:61 size_t size = sizeof(*refs) + j*sizeof(struct object *);
Ditto for "j" pointers.
> - attr.c:220 sizeof(*res) +
Overallocation to have at least "num_attr" instances of "struct
attr_state" (plus name string if needed, which is stored using location
past state[num_attr]).
> - remote.c:467 memset(ret, 0, sizeof(struct ref) + namelen);
Clearing an arena that was overallocated to have at least namelen
elements of char[] on the line immediately before this, with matching
size. All callers pass namelen = strlen(name) + 1 so we are Ok even
when FLEX_ARRAY gives no extra space.
> - remote.c:474 memcpy(ret, ref, sizeof(struct ref) + strlen(ref->name) + 1);
Ditto.
> - transport.c:491 memset(ref, 0, sizeof(struct ref));
A line above overallocates to have enough room for strlen(ref_name) plus
terminating NUL, and after this lines clears the non-flex part, name is
copied. So this overclears a bit, but is harmless.
> diff --git a/unpack-trees.c b/unpack-trees.c
> index e9eb795..aa2513e 100644
> --- a/unpack-trees.c
> +++ b/unpack-trees.c
> @@ -590,7 +590,7 @@ static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
> * a match.
> */
> if (same(old, merge)) {
> - *merge = *old;
> + memcpy(merge, old, offsetof(struct cache_entry, name));
> } else {
> verify_uptodate(old, o);
> invalidate_ce_path(old);
Portability of offsetof() is slightly worrisome, but giving a
compatibility macro is trivial if this turns out to be problematic for
some people.
-
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
