| Message ID | 20210830083717.GU7722@kadam |
|---|---|
| State | Accepted |
| Commit | aaa8e4922c887ff47ad66ef918193682bccc1905 |
| Headers | show |
| Series | [v2,net] net: qrtr: make checks in qrtr_endpoint_post() stricter | expand |
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! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html
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)); }
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(-)