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authorDaniel Borkmann <daniel@iogearbox.net>2018-01-31 14:58:56 +0300
committerAlexei Starovoitov <ast@kernel.org>2018-02-01 18:43:56 +0300
commit65073a67331de3d2cce35607807ddec284e75e81 (patch)
treeaa39697a25f7b47548ca227b13d866558c9b98ce /net/bpf
parent62a06994ced17f295fc51ea0815580ee7ccb668d (diff)
downloadlinux-65073a67331de3d2cce35607807ddec284e75e81.tar.xz
bpf: fix null pointer deref in bpf_prog_test_run_xdp
syzkaller was able to generate the following XDP program ... (18) r0 = 0x0 (61) r5 = *(u32 *)(r1 +12) (04) (u32) r0 += (u32) 0 (95) exit ... and trigger a NULL pointer dereference in ___bpf_prog_run() via bpf_prog_test_run_xdp() where this was attempted to run. Reason is that recent xdp_rxq_info addition to XDP programs updated all drivers, but not bpf_prog_test_run_xdp(), where xdp_buff is set up. Thus when context rewriter does the deref on the netdev it's NULL at runtime. Fix it by using xdp_rxq from loopback dev. __netif_get_rx_queue() helper can also be reused in various other locations later on. Fixes: 02dd3291b2f0 ("bpf: finally expose xdp_rxq_info to XDP bpf-programs") Reported-by: syzbot+1eb094057b338eb1fc00@syzkaller.appspotmail.com Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'net/bpf')
-rw-r--r--net/bpf/test_run.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index a86e6687026e..2ced48662c1f 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -151,6 +151,7 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
{
u32 size = kattr->test.data_size_in;
u32 repeat = kattr->test.repeat;
+ struct netdev_rx_queue *rxqueue;
struct xdp_buff xdp = {};
u32 retval, duration;
void *data;
@@ -165,6 +166,9 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
xdp.data_meta = xdp.data;
xdp.data_end = xdp.data + size;
+ rxqueue = __netif_get_rx_queue(current->nsproxy->net_ns->loopback_dev, 0);
+ xdp.rxq = &rxqueue->xdp_rxq;
+
retval = bpf_test_run(prog, &xdp, repeat, &duration);
if (xdp.data != data + XDP_PACKET_HEADROOM + NET_IP_ALIGN)
size = xdp.data_end - xdp.data;