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[v2,net] net: qrtr: make checks in qrtr_endpoint_post() stricter

Message ID 20210830083717.GU7722@kadam
State Accepted
Commit aaa8e4922c887ff47ad66ef918193682bccc1905
Headers show
Series [v2,net] net: qrtr: make checks in qrtr_endpoint_post() stricter | expand

Commit Message

Dan Carpenter Aug. 30, 2021, 8:37 a.m. UTC
These checks are still not strict enough.  The main problem is that if
"cb->type == QRTR_TYPE_NEW_SERVER" is true then "len - hdrlen" is
guaranteed to be 4 but we need to be at least 16 bytes.  In fact, we
can reject everything smaller than sizeof(*pkt) which is 20 bytes.

Also I don't like the ALIGN(size, 4).  It's better to just insist that
data is needs to be aligned at the start.

Fixes: 0baa99ee353c ("net: qrtr: Allow non-immediate node routing")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2: Fix a % vs & bug.  Thanks, butt3rflyh4ck!

 net/qrtr/qrtr.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org Aug. 30, 2021, 11:30 a.m. UTC | #1
Hello:

This patch was applied to netdev/net-next.git (refs/heads/master):

On Mon, 30 Aug 2021 11:37:17 +0300 you wrote:
> These checks are still not strict enough.  The main problem is that if
> "cb->type == QRTR_TYPE_NEW_SERVER" is true then "len - hdrlen" is
> guaranteed to be 4 but we need to be at least 16 bytes.  In fact, we
> can reject everything smaller than sizeof(*pkt) which is 20 bytes.
> 
> Also I don't like the ALIGN(size, 4).  It's better to just insist that
> data is needs to be aligned at the start.
> 
> [...]

Here is the summary with links:
  - [v2,net] net: qrtr: make checks in qrtr_endpoint_post() stricter
    https://git.kernel.org/netdev/net-next/c/aaa8e4922c88

You are awesome, thank you!
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diff mbox series

Patch

diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index b8508e35d20e..dbb647f5481b 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -493,7 +493,7 @@  int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
 		goto err;
 	}
 
-	if (!size || len != ALIGN(size, 4) + hdrlen)
+	if (!size || size & 3 || len != size + hdrlen)
 		goto err;
 
 	if (cb->dst_port != QRTR_PORT_CTRL && cb->type != QRTR_TYPE_DATA &&
@@ -506,8 +506,12 @@  int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
 
 	if (cb->type == QRTR_TYPE_NEW_SERVER) {
 		/* Remote node endpoint can bridge other distant nodes */
-		const struct qrtr_ctrl_pkt *pkt = data + hdrlen;
+		const struct qrtr_ctrl_pkt *pkt;
 
+		if (size < sizeof(*pkt))
+			goto err;
+
+		pkt = data + hdrlen;
 		qrtr_node_assign(node, le32_to_cpu(pkt->server.node));
 	}