[patch] relay: prevent integer overflow in relay_open()

Dan Carpenter
2012-02-09T10:44:33Z

"subbuf_size" and "n_subbufs" come from the user and they need to be
capped to prevent an integer overflow.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/kernel/relay.c b/kernel/relay.c
index 4335e1d..ab56a17 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -164,10 +164,14 @@ depopulate:
*/
static struct rchan_buf *relay_create_buf(struct rchan *chan)
{
- struct rchan_buf *buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL);
- if (!buf)
+ struct rchan_buf *buf;
+
+ if (chan->n_subbufs > UINT_MAX / sizeof(size_t *))
return NULL;

+ buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL);
+ if (!buf)
+ return NULL;
buf->padding = kmalloc(chan->n_subbufs * sizeof(size_t *), GFP_KERNEL);
if (!buf->padding)
goto free_buf;
@@ -574,6 +578,8 @@ struct rchan *relay_open(const char *base_filename,

if (!(subbuf_size && n_subbufs))
return NULL;
+ if (subbuf_size > UINT_MAX / n_subbufs)
+ return NULL;

chan = kzalloc(sizeof(struct rchan), GFP_KERNEL);
if (!chan)