[Linux-kernel-mentees] [PATCH net v2] xdp: Prevent kernel-infoleak in xsk_getsockopt()
From: Peilin Ye <hidden>
Date: 2020-07-28 05:37:26
Also in:
bpf, lkml, netdev
Subsystem:
networking [general], the rest, xdp sockets (af_xdp) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Magnus Karlsson, Maciej Fijalkowski
xsk_getsockopt() is copying uninitialized stack memory to userspace when
`extra_stats` is `false`. Fix it.
Fixes: 8aa5a33578e9 ("xsk: Add new statistics")
Suggested-by: Dan Carpenter <redacted>
Signed-off-by: Peilin Ye <redacted>
---
Doing `= {};` is sufficient since currently `struct xdp_statistics` is
defined as follows:
struct xdp_statistics {
__u64 rx_dropped;
__u64 rx_invalid_descs;
__u64 tx_invalid_descs;
__u64 rx_ring_full;
__u64 rx_fill_ring_empty_descs;
__u64 tx_ring_empty_descs;
};
When being copied to the userspace, `stats` will not contain any
uninitialized "holes" between struct fields.
Changes in v2:
- Remove the "Cc: stable@vger.kernel.org" tag. (Suggested by Song Liu
[off-list ref])
- Initialize `stats` by assignment instead of using memset().
(Suggested by Song Liu [off-list ref])
net/xdp/xsk.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 26e3bba8c204..b2b533eddebf 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c@@ -840,7 +840,7 @@ static int xsk_getsockopt(struct socket *sock, int level, int optname, switch (optname) { case XDP_STATISTICS: { - struct xdp_statistics stats; + struct xdp_statistics stats = {}; bool extra_stats = true; size_t stats_size;
--
2.25.1
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