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| author | Florian Lehner <dev@der-flo.net> | 2023-11-05 09:58:01 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-11-09 19:07:38 -0800 |
| commit | 9b75dbeb36fcd9fc7ed51d370310d0518a387769 (patch) | |
| tree | d7a194a3c697a90c9b404db8c9f4d000c00021de /kernel/bpf/lpm_trie.c | |
| parent | f2d2c7e1b7c9e8847478769d6e1f8a76b5e91952 (diff) | |
| download | linux-9b75dbeb36fcd9fc7ed51d370310d0518a387769.tar.gz linux-9b75dbeb36fcd9fc7ed51d370310d0518a387769.tar.bz2 linux-9b75dbeb36fcd9fc7ed51d370310d0518a387769.zip | |
bpf, lpm: Fix check prefixlen before walking trie
When looking up an element in LPM trie, the condition 'matchlen ==
trie->max_prefixlen' will never return true, if key->prefixlen is larger
than trie->max_prefixlen. Consequently all elements in the LPM trie will
be visited and no element is returned in the end.
To resolve this, check key->prefixlen first before walking the LPM trie.
Fixes: b95a5c4db09b ("bpf: add a longest prefix match trie map implementation")
Signed-off-by: Florian Lehner <dev@der-flo.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231105085801.3742-1-dev@der-flo.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/lpm_trie.c')
| -rw-r--r-- | kernel/bpf/lpm_trie.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c index 17c7e7782a1f..b32be680da6c 100644 --- a/kernel/bpf/lpm_trie.c +++ b/kernel/bpf/lpm_trie.c @@ -231,6 +231,9 @@ static void *trie_lookup_elem(struct bpf_map *map, void *_key) struct lpm_trie_node *node, *found = NULL; struct bpf_lpm_trie_key *key = _key; + if (key->prefixlen > trie->max_prefixlen) + return NULL; + /* Start walking the trie from the root node ... */ for (node = rcu_dereference_check(trie->root, rcu_read_lock_bh_held()); |