mirror of https://github.com/hak5/openwrt.git
50 lines
1.9 KiB
Diff
50 lines
1.9 KiB
Diff
The gen_stats facility will add a header for the toplevel nlattr of type
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TCA_STATS2 that contains all stats added by qdisc callbacks. A reference
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to this header is stored in the gnet_dump struct, and when all the
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per-qdisc callbacks have finished adding their stats, the length of the
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containing header will be adjusted to the right value.
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However, on architectures that need padding (i.e., that don't set
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CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS), the padding nlattr is added
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before the stats, which means that the stored pointer will point to the
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padding, and so when the header is fixed up, the result is just a very
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big padding nlattr. Because most qdiscs also supply the legacy TCA_STATS
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struct, this problem has been mostly invisible, but we exposed it with
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the netlink attribute-based statistics in CAKE.
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Fix the issue by fixing up the stored pointer if it points to a padding
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nlattr.
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Tested-by: Pete Heist <pete@heistp.net>
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Tested-by: Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
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Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
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---
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net/core/gen_stats.c | 16 ++++++++++++++--
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1 file changed, 14 insertions(+), 2 deletions(-)
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--- a/net/core/gen_stats.c
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+++ b/net/core/gen_stats.c
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@@ -77,8 +77,20 @@ gnet_stats_start_copy_compat(struct sk_b
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d->lock = lock;
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spin_lock_bh(lock);
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}
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- if (d->tail)
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- return gnet_stats_copy(d, type, NULL, 0, padattr);
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+ if (d->tail) {
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+ int ret = gnet_stats_copy(d, type, NULL, 0, padattr);
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+
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+ /* The initial attribute added in gnet_stats_copy() may be
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+ * preceded by a padding attribute, in which case d->tail will
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+ * end up pointing at the padding instead of the real attribute.
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+ * Fix this so gnet_stats_finish_copy() adjusts the length of
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+ * the right attribute.
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+ */
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+ if (ret == 0 && d->tail->nla_type == padattr)
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+ d->tail = (struct nlattr *)((char *)d->tail +
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+ NLA_ALIGN(d->tail->nla_len));
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+ return ret;
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+ }
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return 0;
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}
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