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Subject[PATCH net] net: qrtr: Fix an out of bounds read qrtr_endpoint_post()
This code assumes that the user passed in enough data for a
qrtr_hdr_v1 or qrtr_hdr_v2 struct, but it's not necessarily true. If
the buffer is too small then it will read beyond the end.

Reported-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reported-by: syzbot+b8fe393f999a291a9ea6@syzkaller.appspotmail.com
Fixes: 194ccc88297a ("net: qrtr: Support decoding incoming v2 packets")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
net/qrtr/qrtr.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index 2d8d6131bc5f..7eccbbf6f8ad 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -427,7 +427,7 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
unsigned int ver;
size_t hdrlen;

- if (len & 3)
+ if (len == 0 || len & 3)
return -EINVAL;

skb = netdev_alloc_skb(NULL, len);
@@ -441,6 +441,8 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)

switch (ver) {
case QRTR_PROTO_VER_1:
+ if (len < sizeof(*v1))
+ goto err;
v1 = data;
hdrlen = sizeof(*v1);

@@ -454,6 +456,8 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
size = le32_to_cpu(v1->size);
break;
case QRTR_PROTO_VER_2:
+ if (len < sizeof(*v2))
+ goto err;
v2 = data;
hdrlen = sizeof(*v2) + v2->optlen;

--
2.27.0
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