[PATCH v4 bpf 1/3] libbpf: ensure umem pointer is non-NULL before dereferencing

From: Ciara Loftus <ciara.loftus@intel.com>
To: netdev@vger.kernel.org, bpf@vger.kernel.org,
	magnus.karlsson@intel.com, bjorn@kernel.org,
	alexei.starovoitov@gmail.com
Cc: Ciara Loftus <ciara.loftus@intel.com>
Subject: [PATCH v4 bpf 1/3] libbpf: ensure umem pointer is non-NULL before dereferencing
Date: Wed, 31 Mar 2021 06:12:16 +0000	[thread overview]
Message-ID: <20210331061218.1647-2-ciara.loftus@intel.com> (raw)
In-Reply-To: <20210331061218.1647-1-ciara.loftus@intel.com>

Calls to xsk_socket__create dereference the umem to access the
fill_save and comp_save pointers. Make sure the umem is non-NULL
before doing this.

Fixes: 2f6324a3937f ("libbpf: Support shared umems between queues and devices")

Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
---
 tools/lib/bpf/xsk.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
index 526fc35c0b23..443b0cfb45e8 100644
--- a/tools/lib/bpf/xsk.c
+++ b/tools/lib/bpf/xsk.c
@@ -1019,6 +1019,9 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname,
 		       struct xsk_ring_cons *rx, struct xsk_ring_prod *tx,
 		       const struct xsk_socket_config *usr_config)
 {
+	if (!umem)
+		return -EFAULT;
+
 	return xsk_socket__create_shared(xsk_ptr, ifname, queue_id, umem,
 					 rx, tx, umem->fill_save,
 					 umem->comp_save, usr_config);
-- 
2.17.1

