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.c b/ring_tx.c
index 17d5f26..ee47f3f 100644
--- a/ring_tx.c
+++ b/ring_tx.c
@@ -45,7 +45,7 @@ void destroy_tx_ring(int sock, struct ring *ring)
 	xfree(ring->frames);
 }
 
-void setup_tx_ring_layout(int sock, struct ring *ring, unsigned int size,
+void setup_tx_ring_layout(int sock, struct ring *ring, size_t size,
 			  bool jumbo_support)
 {
 	fmemset(&ring->layout, 0, sizeof(ring->layout));
@@ -86,7 +86,7 @@ retry:
 	if (ret < 0)
 		panic("Cannot allocate TX_RING!\n");
 
-	ring->mm_len = ring->layout.tp_block_size * ring->layout.tp_block_nr;
+	ring->mm_len = (size_t) ring->layout.tp_block_size * ring->layout.tp_block_nr;
 
 	if (verbose) {
 		printf("TX,V2: %.2Lf MiB, %u Frames, each %u Byte allocated\n",