Some bitwise operations are generated when munging paylod expressions.
During delinearization, we attempt to eliminate these operations.
However, this is done before deducing the byte-order or the correct
length in bits of the operands, which means that we don't always handle
multi-byte host-endian operations correctly. Therefore, pass the
bit-length of these expressions to the kernel in order to have it
available during delinearization.
Signed-off-by: Jeremy Sowden <jeremy@xxxxxxxxxx>
---
src/netlink_delinearize.c | 14 ++++++++++++--
src/netlink_linearize.c | 2 ++
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index a1b00dee209a..733977bc526d 100644
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -451,20 +451,28 @@ static struct expr *netlink_parse_bitwise_bool(struct netlink_parse_ctx *ctx,
const struct nftnl_expr *nle,
enum nft_registers sreg,
struct expr *left)
-
{
struct nft_data_delinearize nld;
struct expr *expr, *mask, *xor, *or;
+ unsigned int nbits;
mpz_t m, x, o;
expr = left;
+ nbits = nftnl_expr_get_u32(nle, NFTNL_EXPR_BITWISE_NBITS);
+ if (nbits > 0)
+ expr->len = nbits;
+
nld.value = nftnl_expr_get(nle, NFTNL_EXPR_BITWISE_MASK, &nld.len);
mask = netlink_alloc_value(loc, &nld);
+ if (nbits > 0)
+ mpz_switch_byteorder(mask->value, div_round_up(nbits, BITS_PER_BYTE));
mpz_init_set(m, mask->value);
nld.value = nftnl_expr_get(nle, NFTNL_EXPR_BITWISE_XOR, &nld.len);
- xor = netlink_alloc_value(loc, &nld);
+ xor = netlink_alloc_value(loc, &nld);
+ if (nbits > 0)
+ mpz_switch_byteorder(xor->value, div_round_up(nbits, BITS_PER_BYTE));
mpz_init_set(x, xor->value);
mpz_init_set_ui(o, 0);
@@ -500,6 +508,8 @@ static struct expr *netlink_parse_bitwise_bool(struct netlink_parse_ctx *ctx,
or = netlink_alloc_value(loc, &nld);
mpz_set(or->value, o);
+ if (nbits > 0)
+ mpz_switch_byteorder(or->value, div_round_up(nbits, BITS_PER_BYTE));
expr = binop_expr_alloc(loc, OP_OR, expr, or);
expr->len = left->len;
}
diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index c8bbcb7452b0..4793f3853bee 100644
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -677,6 +677,8 @@ static void netlink_gen_bitwise(struct netlink_linearize_ctx *ctx,
netlink_put_register(nle, NFTNL_EXPR_BITWISE_DREG, dreg);
nftnl_expr_set_u32(nle, NFTNL_EXPR_BITWISE_OP, NFT_BITWISE_BOOL);
nftnl_expr_set_u32(nle, NFTNL_EXPR_BITWISE_LEN, len);
+ if (expr->byteorder == BYTEORDER_HOST_ENDIAN)
+ nftnl_expr_set_u32(nle, NFTNL_EXPR_BITWISE_NBITS, expr->len);
netlink_gen_raw_data(mask, expr->byteorder, len, &nld);
nftnl_expr_set(nle, NFTNL_EXPR_BITWISE_MASK, nld.value, nld.len);
--
2.35.1
