d-sahlberg commented on code in PR #73:
URL: https://github.com/apache/apr/pull/73#discussion_r3255036075
##########
buffer/apr_buffer.c:
##########
@@ -245,6 +245,9 @@ APR_DECLARE(apr_status_t) apr_buffer_arraydup(apr_buffer_t
**out,
for (i = 0; i < nelts; i++) {
/* absolute value is size of mem buffer including optional terminating
zero */
+ if (src->size > APR_BUFFER_MAX) {
+ return APR_EINVAL;
+ }
apr_size_t size = src->size + src->zero_terminated;
Review Comment:
Conceptually fine, however it "only" protects the alloc() call from
allocating more memory than we say a buffer can hold.
If someone is able to manipulate src->size to something more than what is
allocated in src but less than APR_BUFFER_MAX we still have an issue in the
memcpy a little later.
##########
buffer/apr_buffer.c:
##########
@@ -294,9 +297,15 @@ APR_DECLARE(apr_buffer_t *) apr_buffer_cpy(apr_buffer_t
*dst,
else {
/* absolute value is size of mem buffer including optional terminating
zero */
+ if (src->size > APR_BUFFER_MAX) {
+ return NULL;
+ }
apr_size_t size = src->size + src->zero_terminated;
void *mem = alloc(ctx, size);
+ if (!mem) {
+ return NULL;
+ }
memcpy(mem, src->d.mem, size);
Review Comment:
The documentation says nothing of what happens if alloc() returned NULL
(compare with for example apr_buffer_arryadup where it is stated that the
function will handle a NULL return from alloc()).
But since memcpy(0, src, size) is undefined behaviour, I think it is a
reasonable change. Except, perhaps, if it would be an unacceptable API change
to start returning NULL in case of an allocation failure.
##########
buffer/apr_buffer.c:
##########
@@ -294,9 +297,15 @@ APR_DECLARE(apr_buffer_t *) apr_buffer_cpy(apr_buffer_t
*dst,
else {
/* absolute value is size of mem buffer including optional terminating
zero */
+ if (src->size > APR_BUFFER_MAX) {
+ return NULL;
+ }
apr_size_t size = src->size + src->zero_terminated;
Review Comment:
Same comment as above.
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