attr: adjust a mismatched data type

On platforms where `size_t` does not have the same width as `unsigned
long`, passing a pointer to the former when a pointer to the latter is
expected can lead to problems.

Windows and 32-bit Linux are among the affected platforms.

In this instance, we want to store the size of the blob that was read in
that variable. However, `read_blob_data_from_index()` passes that
pointer to `read_object_file()` which expects an `unsigned long *`.
Which means that on affected platforms, the variable is not fully
populated and part of its value is left uninitialized. (On Big-Endian
platforms, this problem would be even worse.)

The consequence is that depending on the uninitialized memory's
contents, we may erroneously reject perfectly fine attributes.

Let's address this by passing a pointer to a variable of the expected
data type.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/attr.c b/attr.c
index f9316d14baf835ee498722a4dc26bd9bd56a8efd..c6498553db301e3c4e81105e817774751565cacf 100644 (file)
--- a/attr.c
+++ b/attr.c
@@ -745,7 +745,7 @@ static struct attr_stack *read_attr_from_index(const struct index_state *istate,
        struct attr_stack *res;
        char *buf, *sp;
        int lineno = 0;
-       size_t size;
+       unsigned long size;
 
        if (!istate)
                return NULL;