• Alban Crequy's avatar
    bpf, lpm: fix lookup bug in map_delete_elem · 7c0cdf0b
    Alban Crequy authored
    trie_delete_elem() was deleting an entry even though it was not matching
    if the prefixlen was correct. This patch adds a check on matchlen.
    
    Reproducer:
    
    $ sudo bpftool map create /sys/fs/bpf/mylpm type lpm_trie key 8 value 1 entries 128 name mylpm flags 1
    $ sudo bpftool map update pinned /sys/fs/bpf/mylpm key hex 10 00 00 00 aa bb cc dd value hex 01
    $ sudo bpftool map dump pinned /sys/fs/bpf/mylpm
    key: 10 00 00 00 aa bb cc dd  value: 01
    Found 1 element
    $ sudo bpftool map delete pinned /sys/fs/bpf/mylpm key hex 10 00 00 00 ff ff ff ff
    $ echo $?
    0
    $ sudo bpftool map dump pinned /sys/fs/bpf/mylpm
    Found 0 elements
    
    A similar reproducer is added in the selftests.
    
    Without the patch:
    
    $ sudo ./tools/testing/selftests/bpf/test_lpm_map
    test_lpm_map: test_lpm_map.c:485: test_lpm_delete: Assertion `bpf_map_delete_elem(map_fd, key) == -1 && errno == ENOENT' failed.
    Aborted
    
    With the patch: test_lpm_map runs without errors.
    
    Fixes: e454cf59 ("bpf: Implement map_delete_elem for BPF_MAP_TYPE_LPM_TRIE")
    Cc: Craig Gallek <kraig@google.com>
    Signed-off-by: default avatarAlban Crequy <alban@kinvolk.io>
    Acked-by: default avatarCraig Gallek <kraig@google.com>
    Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
    7c0cdf0b
lpm_trie.c 21.2 KB