git-fast-import possible memory corruption problem
Internal "allocate in bulk, we will never free this memory anyway"
allocator used in fast-import had a logic to round up the size of the
requested memory block in a wrong place (it computed if the available
space is enough to fit the request first, and then carved a chunk of
memory by size rounded up to the alignment, which could go beyond the
actually available space).
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/fast-import.c b/fast-import.c
index 3c035a5..3276d5d 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -554,6 +554,10 @@
struct mem_pool *p;
void *r;
+ /* round up to a 'uintmax_t' alignment */
+ if (len & (sizeof(uintmax_t) - 1))
+ len += sizeof(uintmax_t) - (len & (sizeof(uintmax_t) - 1));
+
for (p = mem_pool; p; p = p->next_pool)
if ((p->end - p->next_free >= len))
break;
@@ -572,9 +576,6 @@
}
r = p->next_free;
- /* round out to a 'uintmax_t' alignment */
- if (len & (sizeof(uintmax_t) - 1))
- len += sizeof(uintmax_t) - (len & (sizeof(uintmax_t) - 1));
p->next_free += len;
return r;
}
