netdev - [PATCH net-next 4/7] bpf: fix BPF_MAP_LOOKUP

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon,  3 Nov 2014 18:54:13 -0800
From:	Alexei Starovoitov <ast@...mgrid.com>
To:	"David S. Miller" <davem@...emloft.net>
Cc:	Ingo Molnar <mingo@...nel.org>,
	Andy Lutomirski <luto@...capital.net>,
	Daniel Borkmann <dborkman@...hat.com>,
	Hannes Frederic Sowa <hannes@...essinduktion.org>,
	Eric Dumazet <edumazet@...gle.com>, linux-api@...r.kernel.org,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH net-next 4/7] bpf: fix BPF_MAP_LOOKUP_ELEM command return code

fix errno of BPF_MAP_LOOKUP_ELEM command as bpf manpage
described it in commit b4fc1a460f30("Merge branch 'bpf-next'"):
-----
BPF_MAP_LOOKUP_ELEM
    int bpf_lookup_elem(int fd, void *key, void *value)
    {
        union bpf_attr attr = {
            .map_fd = fd,
            .key = ptr_to_u64(key),
            .value = ptr_to_u64(value),
        };

        return bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
    }
    bpf() syscall looks up an element with given key in  a  map  fd.
    If  element  is found it returns zero and stores element's value
    into value.  If element is not found  it  returns  -1  and  sets
    errno to ENOENT.

and further down in manpage:

   ENOENT For BPF_MAP_LOOKUP_ELEM or BPF_MAP_DELETE_ELEM,  indicates  that
          element with given key was not found.
-----

In general all BPF commands return ENOENT when map element is not found
(including BPF_MAP_GET_NEXT_KEY and BPF_MAP_UPDATE_ELEM with
 flags == BPF_MAP_UPDATE_ONLY)

Subsequent patch adds a testsuite to check return values for all of
these combinations.

Signed-off-by: Alexei Starovoitov <ast@...mgrid.com>
---

I don't think this patch is needed for 'net', since 'net' has syscall shell
only. Actual map types and their implementations are being introduced by
this set of patches.

 kernel/bpf/syscall.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index c0d03bf317a2..088ac0b1b106 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -169,7 +169,7 @@ static int map_lookup_elem(union bpf_attr *attr)
 	if (copy_from_user(key, ukey, map->key_size) != 0)
 		goto free_key;
 
-	err = -ESRCH;
+	err = -ENOENT;
 	rcu_read_lock();
 	value = map->ops->map_lookup_elem(map, key);
 	if (!value)
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html