diff options
author | Phil Sutter <phil@nwl.cc> | 2017-12-09 16:52:29 +0100 |
---|---|---|
committer | Florian Westphal <fw@strlen.de> | 2017-12-12 13:24:01 +0100 |
commit | a2c55e04d5a1187914cba2c02810db94de499ace (patch) | |
tree | eb7af207d40217a842ee487ba2c49d0eeda7064a /src | |
parent | 80f5d7fd66895c651c9d1e35b2353f3020ffb538 (diff) |
src: fix protocol context update on big-endian systems
There is an obscure bug on big-endian systems when trying to list a rule
containing the expression 'ct helper tftp' which triggers the assert()
call in mpz_get_type().
Florian identified the cause: ct_expr_pctx_update() is called for the
relational expression which calls mpz_get_uint32() to get RHS value
(assuming it is a protocol number). On big-endian systems, the
misinterpreted value exceeds UINT_MAX.
Expressions' pctx_update() callback should only be called for protocol
matches, so ct_meta_common_postprocess() lacked a check for 'left->flags
& EXPR_F_PROTOCOL' like the one already present in
payload_expr_pctx_update().
In order to fix this in a clean way, this patch introduces a wrapper
relational_expr_pctx_update() to be used instead of directly calling
LHS's pctx_update() callback which unifies the necessary checks (and
adds one more assert):
- assert(expr->ops->type == EXPR_RELATIONAL)
-> This is new, just to ensure the wrapper is called properly.
- assert(expr->op == OP_EQ)
-> This was moved from {ct,meta,payload}_expr_pctx_update().
- left->ops->pctx_update != NULL
-> This was taken from expr_evaluate_relational(), a necessary
requirement for the introduced wrapper to function at all.
- (left->flags & EXPR_F_PROTOCOL) != 0
-> The crucial missing check which led to the problem.
Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>
Diffstat (limited to 'src')
-rw-r--r-- | src/ct.c | 2 | ||||
-rw-r--r-- | src/evaluate.c | 6 | ||||
-rw-r--r-- | src/expression.c | 13 | ||||
-rw-r--r-- | src/meta.c | 2 | ||||
-rw-r--r-- | src/netlink.c | 2 | ||||
-rw-r--r-- | src/netlink_delinearize.c | 4 | ||||
-rw-r--r-- | src/payload.c | 7 |
7 files changed, 19 insertions, 17 deletions
@@ -327,8 +327,6 @@ static void ct_expr_pctx_update(struct proto_ctx *ctx, const struct expr *expr) const struct proto_desc *base = NULL, *desc; uint32_t nhproto; - assert(expr->op == OP_EQ); - nhproto = mpz_get_uint32(right->value); base = ctx->protocol[left->ct.base].desc; diff --git a/src/evaluate.c b/src/evaluate.c index 758e7bbe..7fe738d8 100644 --- a/src/evaluate.c +++ b/src/evaluate.c @@ -746,7 +746,7 @@ static int ct_gen_nh_dependency(struct eval_ctx *ctx, struct expr *ct) constant_data_ptr(ct->ct.nfproto, left->len)); dep = relational_expr_alloc(&ct->location, OP_EQ, left, right); - left->ops->pctx_update(&ctx->pctx, dep); + relational_expr_pctx_update(&ctx->pctx, dep); nstmt = expr_stmt_alloc(&dep->location, dep); @@ -1635,9 +1635,7 @@ static int expr_evaluate_relational(struct eval_ctx *ctx, struct expr **expr) * Update protocol context for payload and meta iiftype * equality expressions. */ - if (left->flags & EXPR_F_PROTOCOL && - left->ops->pctx_update) - left->ops->pctx_update(&ctx->pctx, rel); + relational_expr_pctx_update(&ctx->pctx, rel); if (left->ops->type == EXPR_CONCAT) return 0; diff --git a/src/expression.c b/src/expression.c index 273038e6..393c1b2b 100644 --- a/src/expression.c +++ b/src/expression.c @@ -600,6 +600,19 @@ struct expr *relational_expr_alloc(const struct location *loc, enum ops op, return expr; } +void relational_expr_pctx_update(struct proto_ctx *ctx, + const struct expr *expr) +{ + const struct expr *left = expr->left; + + assert(expr->ops->type == EXPR_RELATIONAL); + assert(expr->op == OP_EQ); + + if (left->ops->pctx_update && + (left->flags & EXPR_F_PROTOCOL)) + left->ops->pctx_update(ctx, expr); +} + static void range_expr_print(const struct expr *expr, struct output_ctx *octx) { octx->numeric += NFT_NUMERIC_ALL + 1; @@ -482,8 +482,6 @@ static void meta_expr_pctx_update(struct proto_ctx *ctx, const struct proto_desc *desc; uint8_t protonum; - assert(expr->op == OP_EQ); - switch (left->meta.key) { case NFT_META_IIFTYPE: if (h->base < PROTO_BASE_NETWORK_HDR && diff --git a/src/netlink.c b/src/netlink.c index 6735971a..8653ae6e 100644 --- a/src/netlink.c +++ b/src/netlink.c @@ -2730,7 +2730,7 @@ restart: list_add_tail(&stmt->list, &unordered); desc = ctx->protocol[base].desc; - lhs->ops->pctx_update(ctx, rel); + relational_expr_pctx_update(ctx, rel); } expr_free(rhs); diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c index 67dbd27d..2637f4ba 100644 --- a/src/netlink_delinearize.c +++ b/src/netlink_delinearize.c @@ -1329,7 +1329,7 @@ static void payload_match_expand(struct rule_pp_ctx *ctx, nexpr = relational_expr_alloc(&expr->location, expr->op, left, tmp); if (expr->op == OP_EQ) - left->ops->pctx_update(&ctx->pctx, nexpr); + relational_expr_pctx_update(&ctx->pctx, nexpr); nstmt = expr_stmt_alloc(&ctx->stmt->location, nexpr); list_add_tail(&nstmt->list, &ctx->stmt->list); @@ -1397,7 +1397,7 @@ static void ct_meta_common_postprocess(struct rule_pp_ctx *ctx, if (expr->right->ops->type == EXPR_RANGE) break; - expr->left->ops->pctx_update(&ctx->pctx, expr); + relational_expr_pctx_update(&ctx->pctx, expr); if (ctx->pdctx.pbase == PROTO_BASE_INVALID && left->flags & EXPR_F_PROTOCOL) { diff --git a/src/payload.c b/src/payload.c index aa8a95ad..60090acc 100644 --- a/src/payload.c +++ b/src/payload.c @@ -84,11 +84,6 @@ static void payload_expr_pctx_update(struct proto_ctx *ctx, const struct proto_desc *base, *desc; unsigned int proto = 0; - if (!(left->flags & EXPR_F_PROTOCOL)) - return; - - assert(expr->op == OP_EQ); - /* Export the data in the correct byte order */ assert(right->len / BITS_PER_BYTE <= sizeof(proto)); mpz_export_data(constant_data_ptr(proto, right->len), right->value, @@ -240,7 +235,7 @@ static int payload_add_dependency(struct eval_ctx *ctx, return expr_error(ctx->msgs, expr, "dependency statement is invalid"); } - left->ops->pctx_update(&ctx->pctx, dep); + relational_expr_pctx_update(&ctx->pctx, dep); *res = stmt; return 0; } |