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, 4 insertions, 2 deletions

diff --git a/trafgen.c b/trafgen.c
index 489ff53..43148b7 100644
--- a/trafgen.c
+++ b/trafgen.c
@@ -56,7 +56,8 @@
 
 struct ctx {
 	bool rand, rfraw, jumbo_support, verbose, smoke_test, enforce, qdisc_path;
-	unsigned long num, reserve_size;
+	size_t reserve_size;
+	unsigned long num;
 	unsigned int cpus;
 	uid_t uid; gid_t gid;
 	char *device, *device_trans, *rhost;
@@ -590,7 +591,8 @@ static void xmit_fastpath_or_die(struct ctx *ctx, int cpu, unsigned long orig_nu
 	int ifindex = device_ifindex(ctx->device);
 	uint8_t *out = NULL;
 	unsigned int it = 0;
-	unsigned long num = 1, i = 0, size;
+	unsigned long num = 1, i = 0;
+	size_t size;
 	struct ring tx_ring;
 	struct frame_map *hdr;
 	struct timeval start, end, diff;