| Message ID | 20210827132428.GA8934@kili |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [net-next] net: qrtr: make checks in qrtr_endpoint_post() stricter | expand |
On Fri, Aug 27, 2021 at 9:24 PM Dan Carpenter <dan.carpenter@oracle.com> 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. > > Fixes: 0baa99ee353c ("net: qrtr: Allow non-immediate node routing") > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> > --- > This was from review. Not tested. > > net/qrtr/qrtr.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > 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) Hi, (size % 3) is wrong, is it (size & 3), right ? > 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)) Yes, the size should not be smaller than sizeof(*pkt). > + goto err; > + > + pkt = data + hdrlen; > qrtr_node_assign(node, le32_to_cpu(pkt->server.node)); > } > > -- > 2.20.1 > Regards, butt3rflyh4ck
On Fri, Aug 27, 2021 at 11:35:31PM +0800, butt3rflyh4ck wrote: > On Fri, Aug 27, 2021 at 9:24 PM Dan Carpenter <dan.carpenter@oracle.com> 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. > > > > Fixes: 0baa99ee353c ("net: qrtr: Allow non-immediate node routing") > > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> > > --- > > This was from review. Not tested. > > > > net/qrtr/qrtr.c | 8 ++++++-- > > 1 file changed, 6 insertions(+), 2 deletions(-) > > > > 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) > > Hi, (size % 3) is wrong, is it (size & 3), right ? > Yeah. Thanks for catching that. I means & 3. regards, dan carpenter
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> --- This was from review. Not tested. net/qrtr/qrtr.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)