ring: Consistently use size_t to specify ring size

The mm_len member of struct ring is of type size_t, but in the code
paths leading to set it, unsigned int is used. In circumstances where
unsigned int is 32 bit and size_t is 64 bit, this could lead to an
integer overflow, which causes an improper ring size being mmap()'ed in
mmap_ring_generic().

In order to prevent this, consistently use size_t to store the ring
size, since this is also what mmap() takes as its `length' parameter.

This now allows to specify ring sizes larger than 4 GiB for both
netsniff-ng and trafgen (fixes #90).

Reported-by: Jon Schipp <jonschipp@gmail.com>
Reported-by: Michał Purzyński <michalpurzynski1@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

1 files changed, 2 insertions, 2 deletions

diff --git a/ring_tx.h b/ring_tx.h
index ea99fc6..70dd401 100644
--- a/ring_tx.h
+++ b/ring_tx.h
@@ -19,8 +19,8 @@ extern void create_tx_ring(int sock, struct ring *ring, int verbose);
 extern void mmap_tx_ring(int sock, struct ring *ring);
 extern void alloc_tx_ring_frames(int sock, struct ring *ring);
 extern void bind_tx_ring(int sock, struct ring *ring, int ifindex);
-extern void setup_tx_ring_layout(int sock, struct ring *ring,
-				 unsigned int size, bool jumbo_support);
+extern void setup_tx_ring_layout(int sock, struct ring *ring, size_t size,
+				 bool jumbo_support);
 extern void set_packet_loss_discard(int sock);
 
 static inline int user_may_pull_from_tx(struct tpacket2_hdr *hdr)