fix invalid read in aligned_alloc

[musl] / src / malloc / aligned_alloc.c

diff --git a/src/malloc/aligned_alloc.c b/src/malloc/aligned_alloc.c
index d623420..158dba4 100644 (file)
--- a/src/malloc/aligned_alloc.c
+++ b/src/malloc/aligned_alloc.c
@@ -31,8 +31,6 @@ void *aligned_alloc(size_t align, size_t len)
                return NULL;
 
        header = ((size_t *)mem)[-1];
-       end = mem + (header & -8);
-       footer = ((size_t *)end)[-2];
        new = (void *)((uintptr_t)mem + align-1 & -align);
 
        if (!(header & 7)) {
@@ -41,6 +39,9 @@ void *aligned_alloc(size_t align, size_t len)
                return new;
        }
 
+       end = mem + (header & -8);
+       footer = ((size_t *)end)[-2];
+
        ((size_t *)mem)[-1] = header&7 | new-mem;
        ((size_t *)new)[-2] = footer&7 | new-mem;
        ((size_t *)new)[-1] = header&7 | end-new;