net: filter: seccomp: fix wrong decoding of BPF_S_ANC_SECCOMP_LD_W

While reviewing seccomp code, we found that BPF_S_ANC_SECCOMP_LD_W has
been wrongly decoded by commit a8fc927780 ("sk-filter: Add ability to
get socket filter program (v2)") into the opcode BPF_LD|BPF_B|BPF_ABS
although it should have been decoded as BPF_LD|BPF_W|BPF_ABS.

In practice, this should not have much side-effect though, as such
conversion is/was being done through prctl(2) PR_SET_SECCOMP. Reverse
operation PR_GET_SECCOMP will only return the current seccomp mode, but
not the filter itself. Since the transition to the new BPF infrastructure,
it's also not used anymore, so we can simply remove this as it's
unreachable.

Fixes: a8fc927780 ("sk-filter: Add ability to get socket filter program (v2)")
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 262dcbb75ffe3b343ae1513d715e2eae5fd1d902..024fd03e5d182d5670ee2c60005cbea43f8a83e8 100644 (file)
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -220,7 +220,6 @@ enum {
        BPF_S_ANC_RXHASH,
        BPF_S_ANC_CPU,
        BPF_S_ANC_ALU_XOR_X,
-       BPF_S_ANC_SECCOMP_LD_W,
        BPF_S_ANC_VLAN_TAG,
        BPF_S_ANC_VLAN_TAG_PRESENT,
        BPF_S_ANC_PAY_OFFSET,

diff --git a/net/core/filter.c b/net/core/filter.c
index 0e0856f5d708457b6de9a71df82ff2547f97c155..cd58614660cf54e1431392c5045bbdc9478336e6 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1743,7 +1743,6 @@ void sk_decode_filter(struct sock_filter *filt, struct sock_filter *to)
                [BPF_S_ANC_RXHASH]      = BPF_LD|BPF_B|BPF_ABS,
                [BPF_S_ANC_CPU]         = BPF_LD|BPF_B|BPF_ABS,
                [BPF_S_ANC_ALU_XOR_X]   = BPF_LD|BPF_B|BPF_ABS,
-               [BPF_S_ANC_SECCOMP_LD_W] = BPF_LD|BPF_B|BPF_ABS,
                [BPF_S_ANC_VLAN_TAG]    = BPF_LD|BPF_B|BPF_ABS,
                [BPF_S_ANC_VLAN_TAG_PRESENT] = BPF_LD|BPF_B|BPF_ABS,
                [BPF_S_ANC_PAY_OFFSET]  = BPF_LD|BPF_B|BPF_ABS,