filter: add XOR instruction for use with X/K

SKF_AD_ALU_XOR_X has been added a while ago, but as an 'ancillary'
operation that is invoked through a negative offset in K within BPF
load operations. Since BPF_MOD has recently been added, BPF_XOR should
also be part of the common ALU operations. Removing SKF_AD_ALU_XOR_X
might not be an option since this is exposed to user space.

Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 3 deletions

diff --git a/net/core/filter.c b/net/core/filter.c
index fbe3a8d12570..3d92ebb7fbcf 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -187,6 +187,13 @@ unsigned int sk_run_filter(const struct sk_buff *skb,
                 case BPF_S_ALU_OR_K:
                         A |= K;
                         continue;
+                case BPF_S_ANC_ALU_XOR_X:
+                case BPF_S_ALU_XOR_X:
+                        A ^= X;
+                        continue;
+                case BPF_S_ALU_XOR_K:
+                        A ^= K;
+                        continue;
                 case BPF_S_ALU_LSH_X:
                         A <<= X;
                         continue;
@@ -334,9 +341,6 @@ load_b:
                 case BPF_S_ANC_CPU:
                         A = raw_smp_processor_id();
                         continue;
-                case BPF_S_ANC_ALU_XOR_X:
-                        A ^= X;
-                        continue;
                 case BPF_S_ANC_NLATTR: {
                         struct nlattr *nla;
 
@@ -483,6 +487,8 @@ int sk_chk_filter(struct sock_filter *filter, unsigned int flen)
                 [BPF_ALU|BPF_AND|BPF_X]  = BPF_S_ALU_AND_X,
                 [BPF_ALU|BPF_OR|BPF_K]   = BPF_S_ALU_OR_K,
                 [BPF_ALU|BPF_OR|BPF_X]   = BPF_S_ALU_OR_X,
+                [BPF_ALU|BPF_XOR|BPF_K]  = BPF_S_ALU_XOR_K,
+                [BPF_ALU|BPF_XOR|BPF_X]  = BPF_S_ALU_XOR_X,
                 [BPF_ALU|BPF_LSH|BPF_K]  = BPF_S_ALU_LSH_K,
                 [BPF_ALU|BPF_LSH|BPF_X]  = BPF_S_ALU_LSH_X,
                 [BPF_ALU|BPF_RSH|BPF_K]  = BPF_S_ALU_RSH_K,