| Message ID | 1498913642-32459-4-git-send-email-steffan.karger@fox-it.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [1/5] buffer_list_aggregate_separator(): add unit tests | expand |
diff --git a/src/openvpn/buffer.c b/src/openvpn/buffer.c index 2700ad1..ecbdc1b 100644 --- a/src/openvpn/buffer.c +++ b/src/openvpn/buffer.c @@ -1261,8 +1261,7 @@ buffer_list_aggregate_separator(struct buffer_list *bl, const size_t max_len, struct buffer_entry *e = bl->head, *f; ALLOC_OBJ_CLEAR(f, struct buffer_entry); - f->buf.data = malloc(size); - check_malloc_return(f->buf.data); + f->buf = alloc_buf(size+1); /* prevent 0-byte malloc */ f->buf.capacity = size; for (i = 0; e && i < count; ++i) {
As pointed out in finding OVPN-05 of the cryptograpy engineering audit (funded by Private Internet Access), buffer_list_aggregate_separator() could perform a 0-byte malloc when called with a list of 0-length buffers and a "" separator. If other could would later try to access that buffer memory, this would result in undefined behaviour. To prevent this, always malloc() 1 byte. To simplify as we go, use alloc_buf() to allocate the buffer. This has the additional benefit that the actual buffer data (not the contents) is zero-terminated, because alloc_buf() calls calloc() and we have 1 extra byte of data. Signed-off-by: Steffan Karger <steffan.karger@fox-it.com> --- src/openvpn/buffer.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)