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@xxxxxxxxx>
Signed-off-by: Phil Sutter <phil@xxxxxx>
---
include/expression.h | 3 +++
src/ct.c | 2 --
src/evaluate.c | 6 ++----
src/expression.c | 15 +++++++++++++++
src/meta.c | 2 --
src/netlink.c | 2 +-
src/netlink_delinearize.c | 4 ++--
src/payload.c | 7 +------
8 files changed, 24 insertions(+), 17 deletions(-)
diff --git a/include/expression.h b/include/expression.h
index 215cbc98e8d70..915ce0bad04df 100644
--- a/include/expression.h
+++ b/include/expression.h
@@ -369,6 +369,9 @@ extern struct expr *binop_expr_alloc(const struct location *loc, enum ops op,
extern struct expr *relational_expr_alloc(const struct location *loc, enum ops op,
struct expr *left, struct expr *right);
+extern void relational_expr_pctx_update(struct proto_ctx *ctx,
+ const struct expr *expr);
+
extern struct expr *verdict_expr_alloc(const struct location *loc,
int verdict, const char *chain);
diff --git a/src/ct.c b/src/ct.c
index 4633127d5ec6d..d5347974bd0d5 100644
--- a/src/ct.c
+++ b/src/ct.c
@@ -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 758e7bbe59393..7fe738d8d590a 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 273038e62d2e9..9b521e6c7e673 100644
--- a/src/expression.c
+++ b/src/expression.c
@@ -600,6 +600,21 @@ 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)
+{
+ 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))
+ return;
+
+ 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;
diff --git a/src/meta.c b/src/meta.c
index 28aebe396f17e..687de8cda8c35 100644
--- a/src/meta.c
+++ b/src/meta.c
@@ -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 6735971ac1f39..8653ae6e70c76 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 67dbd27dd7a70..2637f4baaec4c 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 aa8a95ad59f1c..60090accbcd8b 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;
}
--
2.13.1
--
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