path: root/net
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authorDavid Ahern <dsahern@gmail.com>2020-01-10 09:03:58 -0800
committerDavid S. Miller <davem@davemloft.net>2020-01-10 11:36:36 -0800
commit9827c0634e461703abf81e8cc8b7adf5da5886d0 (patch)
treee0fe863e9f526b1dca445458610f1769b8c61696 /net
parentb509750f8e87794c97dc199a92ea4e4e47db0b16 (diff)
ipv4: Detect rollover in specific fib table dump
Sven-Haegar reported looping on fib dumps when route has been added to a table. The looping is caused by the key rolling over from FFFFFFFF to 0. When dumping a specific table only, we need a means to detect when the table dump is done. The key and count saved to cb args are both 0 only at the start of the table dump. If key is 0 and count > 0, then we are in the rollover case. Detect and return to avoid looping. This only affects dumps of a specific table; for dumps of all tables (the case prior to the change in the Fixes tag) inet_dump_fib moved the entry counter to the next table and reset the cb args used by fib_table_dump and fn_trie_dump_leaf, so the rollover ffffffff back to 0 did not cause looping with the dumps. Fixes: effe67926624 ("net: Enable kernel side filtering of route dumps") Reported-by: Sven-Haegar Koch <haegar@sdinet.de> Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
1 files changed, 6 insertions, 0 deletions
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index b9df9c09b84e..195469a13371 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -2193,6 +2193,12 @@ int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
int count = cb->args[2];
t_key key = cb->args[3];
+ /* First time here, count and key are both always 0. Count > 0
+ * and key == 0 means the dump has wrapped around and we are done.
+ */
+ if (count && !key)
+ return skb->len;
while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
int err;

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