From 3d0ce3c19d319a5aae806b617905cfa1ee7f87f4 Mon Sep 17 00:00:00 2001 From: Thomas Haller Date: Wed, 20 Sep 2023 16:26:08 +0200 Subject: expression: cleanup expr_ops_by_type() and handle u32 input Make fewer assumptions about the underlying integer type of the enum. Instead, be clear about where we have an untrusted uint32_t from netlink and an enum. Rename expr_ops_by_type() to expr_ops_by_type_u32() to make this clearer. Later we might make the enum as packed, when this starts to matter more. Also, only the code path expr_ops() wants strict validation and assert against valid enum values. Move the assertion out of __expr_ops_by_type(). Then expr_ops_by_type_u32() does not need to duplicate the handling of EXPR_INVALID. We still need to duplicate the check against EXPR_MAX, to ensure that the uint32_t value can be cast to an enum value. [ Remove cast on EXPR_MAX. --pablo ] Signed-off-by: Thomas Haller Signed-off-by: Pablo Neira Ayuso --- src/expression.c | 23 ++++++++++++----------- src/netlink.c | 4 ++-- 2 files changed, 14 insertions(+), 13 deletions(-) (limited to 'src') diff --git a/src/expression.c b/src/expression.c index 87d5a9fc..c9147950 100644 --- a/src/expression.c +++ b/src/expression.c @@ -995,7 +995,7 @@ static struct expr *concat_expr_parse_udata(const struct nftnl_udata *attr) goto err_free; etype = nftnl_udata_get_u32(nest_ud[NFTNL_UDATA_SET_KEY_CONCAT_SUB_TYPE]); - ops = expr_ops_by_type(etype); + ops = expr_ops_by_type_u32(etype); if (!ops || !ops->parse_udata) goto err_free; @@ -1509,9 +1509,7 @@ void range_expr_value_high(mpz_t rop, const struct expr *expr) static const struct expr_ops *__expr_ops_by_type(enum expr_types etype) { switch (etype) { - case EXPR_INVALID: - BUG("Invalid expression ops requested"); - break; + case EXPR_INVALID: break; case EXPR_VERDICT: return &verdict_expr_ops; case EXPR_SYMBOL: return &symbol_expr_ops; case EXPR_VARIABLE: return &variable_expr_ops; @@ -1543,20 +1541,23 @@ static const struct expr_ops *__expr_ops_by_type(enum expr_types etype) case EXPR_FLAGCMP: return &flagcmp_expr_ops; } - BUG("Unknown expression type %d\n", etype); + return NULL; } const struct expr_ops *expr_ops(const struct expr *e) { - return __expr_ops_by_type(e->etype); + const struct expr_ops *ops; + + ops = __expr_ops_by_type(e->etype); + if (!ops) + BUG("Unknown expression type %d\n", e->etype); + + return ops; } -const struct expr_ops *expr_ops_by_type(enum expr_types value) +const struct expr_ops *expr_ops_by_type_u32(uint32_t value) { - /* value might come from unreliable source, such as "udata" - * annotation of set keys. Avoid BUG() assertion. - */ - if (value == EXPR_INVALID || value > EXPR_MAX) + if (value > EXPR_MAX) return NULL; return __expr_ops_by_type(value); diff --git a/src/netlink.c b/src/netlink.c index 70ebf382..8af579c7 100644 --- a/src/netlink.c +++ b/src/netlink.c @@ -878,8 +878,8 @@ static struct expr *set_make_key(const struct nftnl_udata *attr) { const struct nftnl_udata *ud[NFTNL_UDATA_SET_TYPEOF_MAX + 1] = {}; const struct expr_ops *ops; - enum expr_types etype; struct expr *expr; + uint32_t etype; int err; if (!attr) @@ -895,7 +895,7 @@ static struct expr *set_make_key(const struct nftnl_udata *attr) return NULL; etype = nftnl_udata_get_u32(ud[NFTNL_UDATA_SET_TYPEOF_EXPR]); - ops = expr_ops_by_type(etype); + ops = expr_ops_by_type_u32(etype); if (!ops) return NULL; -- cgit v1.2.3