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* [iptables PATCH] nft: Exit if nftnl_alloc_expr fails
@ 2022-06-14 16:44 Phil Sutter
  2022-06-15  7:04 ` Pablo Neira Ayuso
  0 siblings, 1 reply; 3+ messages in thread
From: Phil Sutter @ 2022-06-14 16:44 UTC (permalink / raw)
  To: netfilter-devel; +Cc: Pablo Neira Ayuso

In some code-paths, 'reg' pointer remaining unallocated is used later so
at least minimal error checking is necessary. Given that a call to
nftnl_alloc_expr() should never fail with sane argument, complain and
exit if it happens.

Fixes: 7e38890c6b4fb ("nft: prepare for dynamic register allocation")
Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 iptables/nft-shared.c | 32 +++++++++++++++++---------------
 1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/iptables/nft-shared.c b/iptables/nft-shared.c
index 27e95c1ae4f38..d603e7c9d663b 100644
--- a/iptables/nft-shared.c
+++ b/iptables/nft-shared.c
@@ -40,15 +40,25 @@ extern struct nft_family_ops nft_family_ops_ipv6;
 extern struct nft_family_ops nft_family_ops_arp;
 extern struct nft_family_ops nft_family_ops_bridge;
 
+static struct nftnl_expr *nftnl_expr_alloc_or_die(const char *name)
+{
+	struct nftnl_expr *expr = nftnl_expr_alloc(name);
+
+	if (expr)
+		return expr;
+
+
+	xtables_error(RESOURCE_PROBLEM,
+		      "Failed to allocate nftnl expression '%s'", name);
+}
+
 void add_meta(struct nft_handle *h, struct nftnl_rule *r, uint32_t key,
 	      uint8_t *dreg)
 {
 	struct nftnl_expr *expr;
 	uint8_t reg;
 
-	expr = nftnl_expr_alloc("meta");
-	if (expr == NULL)
-		return;
+	expr = nftnl_expr_alloc_or_die("meta");
 
 	reg = NFT_REG_1;
 	nftnl_expr_set_u32(expr, NFTNL_EXPR_META_KEY, key);
@@ -64,9 +74,7 @@ void add_payload(struct nft_handle *h, struct nftnl_rule *r,
 	struct nftnl_expr *expr;
 	uint8_t reg;
 
-	expr = nftnl_expr_alloc("payload");
-	if (expr == NULL)
-		return;
+	expr = nftnl_expr_alloc_or_die("payload");
 
 	reg = NFT_REG_1;
 	nftnl_expr_set_u32(expr, NFTNL_EXPR_PAYLOAD_BASE, base);
@@ -85,9 +93,7 @@ void add_bitwise_u16(struct nft_handle *h, struct nftnl_rule *r,
 	struct nftnl_expr *expr;
 	uint8_t reg;
 
-	expr = nftnl_expr_alloc("bitwise");
-	if (expr == NULL)
-		return;
+	expr = nftnl_expr_alloc_or_die("bitwise");
 
 	reg = NFT_REG_1;
 	nftnl_expr_set_u32(expr, NFTNL_EXPR_BITWISE_SREG, sreg);
@@ -107,9 +113,7 @@ void add_bitwise(struct nft_handle *h, struct nftnl_rule *r,
 	uint32_t xor[4] = { 0 };
 	uint8_t reg = *dreg;
 
-	expr = nftnl_expr_alloc("bitwise");
-	if (expr == NULL)
-		return;
+	expr = nftnl_expr_alloc_or_die("bitwise");
 
 	nftnl_expr_set_u32(expr, NFTNL_EXPR_BITWISE_SREG, sreg);
 	nftnl_expr_set_u32(expr, NFTNL_EXPR_BITWISE_DREG, reg);
@@ -126,9 +130,7 @@ void add_cmp_ptr(struct nftnl_rule *r, uint32_t op, void *data, size_t len,
 {
 	struct nftnl_expr *expr;
 
-	expr = nftnl_expr_alloc("cmp");
-	if (expr == NULL)
-		return;
+	expr = nftnl_expr_alloc_or_die("cmp");
 
 	nftnl_expr_set_u32(expr, NFTNL_EXPR_CMP_SREG, sreg);
 	nftnl_expr_set_u32(expr, NFTNL_EXPR_CMP_OP, op);
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [iptables PATCH] nft: Exit if nftnl_alloc_expr fails
  2022-06-14 16:44 [iptables PATCH] nft: Exit if nftnl_alloc_expr fails Phil Sutter
@ 2022-06-15  7:04 ` Pablo Neira Ayuso
  2022-06-15  8:47   ` Phil Sutter
  0 siblings, 1 reply; 3+ messages in thread
From: Pablo Neira Ayuso @ 2022-06-15  7:04 UTC (permalink / raw)
  To: Phil Sutter; +Cc: netfilter-devel

On Tue, Jun 14, 2022 at 06:44:57PM +0200, Phil Sutter wrote:
> In some code-paths, 'reg' pointer remaining unallocated is used later so
> at least minimal error checking is necessary. Given that a call to
> nftnl_alloc_expr() should never fail with sane argument, complain and
> exit if it happens.
> 
> Fixes: 7e38890c6b4fb ("nft: prepare for dynamic register allocation")
> Signed-off-by: Phil Sutter <phil@nwl.cc>
> ---
>  iptables/nft-shared.c | 32 +++++++++++++++++---------------
>  1 file changed, 17 insertions(+), 15 deletions(-)
> 
> diff --git a/iptables/nft-shared.c b/iptables/nft-shared.c
> index 27e95c1ae4f38..d603e7c9d663b 100644
> --- a/iptables/nft-shared.c
> +++ b/iptables/nft-shared.c
> @@ -40,15 +40,25 @@ extern struct nft_family_ops nft_family_ops_ipv6;
>  extern struct nft_family_ops nft_family_ops_arp;
>  extern struct nft_family_ops nft_family_ops_bridge;
>  
> +static struct nftnl_expr *nftnl_expr_alloc_or_die(const char *name)

better call this:

xt_nftnl_expr_alloc()

or such, to not enter nftnl_ namespace, I'd suggest.

> +{
> +	struct nftnl_expr *expr = nftnl_expr_alloc(name);
> +
> +	if (expr)
> +		return expr;
> +

extra line space.

> +
> +	xtables_error(RESOURCE_PROBLEM,
> +		      "Failed to allocate nftnl expression '%s'", name);
> +}
> +
>  void add_meta(struct nft_handle *h, struct nftnl_rule *r, uint32_t key,
>  	      uint8_t *dreg)
>  {
>  	struct nftnl_expr *expr;
>  	uint8_t reg;
>  
> -	expr = nftnl_expr_alloc("meta");
> -	if (expr == NULL)
> -		return;
> +	expr = nftnl_expr_alloc_or_die("meta");
>  
>  	reg = NFT_REG_1;
>  	nftnl_expr_set_u32(expr, NFTNL_EXPR_META_KEY, key);
> @@ -64,9 +74,7 @@ void add_payload(struct nft_handle *h, struct nftnl_rule *r,
>  	struct nftnl_expr *expr;
>  	uint8_t reg;
>  
> -	expr = nftnl_expr_alloc("payload");
> -	if (expr == NULL)
> -		return;
> +	expr = nftnl_expr_alloc_or_die("payload");
>  
>  	reg = NFT_REG_1;
>  	nftnl_expr_set_u32(expr, NFTNL_EXPR_PAYLOAD_BASE, base);
> @@ -85,9 +93,7 @@ void add_bitwise_u16(struct nft_handle *h, struct nftnl_rule *r,
>  	struct nftnl_expr *expr;
>  	uint8_t reg;
>  
> -	expr = nftnl_expr_alloc("bitwise");
> -	if (expr == NULL)
> -		return;
> +	expr = nftnl_expr_alloc_or_die("bitwise");
>  
>  	reg = NFT_REG_1;
>  	nftnl_expr_set_u32(expr, NFTNL_EXPR_BITWISE_SREG, sreg);
> @@ -107,9 +113,7 @@ void add_bitwise(struct nft_handle *h, struct nftnl_rule *r,
>  	uint32_t xor[4] = { 0 };
>  	uint8_t reg = *dreg;
>  
> -	expr = nftnl_expr_alloc("bitwise");
> -	if (expr == NULL)
> -		return;
> +	expr = nftnl_expr_alloc_or_die("bitwise");
>  
>  	nftnl_expr_set_u32(expr, NFTNL_EXPR_BITWISE_SREG, sreg);
>  	nftnl_expr_set_u32(expr, NFTNL_EXPR_BITWISE_DREG, reg);
> @@ -126,9 +130,7 @@ void add_cmp_ptr(struct nftnl_rule *r, uint32_t op, void *data, size_t len,
>  {
>  	struct nftnl_expr *expr;
>  
> -	expr = nftnl_expr_alloc("cmp");
> -	if (expr == NULL)
> -		return;
> +	expr = nftnl_expr_alloc_or_die("cmp");
>  
>  	nftnl_expr_set_u32(expr, NFTNL_EXPR_CMP_SREG, sreg);
>  	nftnl_expr_set_u32(expr, NFTNL_EXPR_CMP_OP, op);
> -- 
> 2.34.1
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [iptables PATCH] nft: Exit if nftnl_alloc_expr fails
  2022-06-15  7:04 ` Pablo Neira Ayuso
@ 2022-06-15  8:47   ` Phil Sutter
  0 siblings, 0 replies; 3+ messages in thread
From: Phil Sutter @ 2022-06-15  8:47 UTC (permalink / raw)
  To: Pablo Neira Ayuso; +Cc: netfilter-devel

On Wed, Jun 15, 2022 at 09:04:00AM +0200, Pablo Neira Ayuso wrote:
> On Tue, Jun 14, 2022 at 06:44:57PM +0200, Phil Sutter wrote:
> > In some code-paths, 'reg' pointer remaining unallocated is used later so
> > at least minimal error checking is necessary. Given that a call to
> > nftnl_alloc_expr() should never fail with sane argument, complain and
> > exit if it happens.
> > 
> > Fixes: 7e38890c6b4fb ("nft: prepare for dynamic register allocation")
> > Signed-off-by: Phil Sutter <phil@nwl.cc>
> > ---
> >  iptables/nft-shared.c | 32 +++++++++++++++++---------------
> >  1 file changed, 17 insertions(+), 15 deletions(-)
> > 
> > diff --git a/iptables/nft-shared.c b/iptables/nft-shared.c
> > index 27e95c1ae4f38..d603e7c9d663b 100644
> > --- a/iptables/nft-shared.c
> > +++ b/iptables/nft-shared.c
> > @@ -40,15 +40,25 @@ extern struct nft_family_ops nft_family_ops_ipv6;
> >  extern struct nft_family_ops nft_family_ops_arp;
> >  extern struct nft_family_ops nft_family_ops_bridge;
> >  
> > +static struct nftnl_expr *nftnl_expr_alloc_or_die(const char *name)
> 
> better call this:
> 
> xt_nftnl_expr_alloc()
> 
> or such, to not enter nftnl_ namespace, I'd suggest.

ACK, will do.

> > +{
> > +	struct nftnl_expr *expr = nftnl_expr_alloc(name);
> > +
> > +	if (expr)
> > +		return expr;
> > +
> 
> extra line space.

Oh, thanks.

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-06-15  8:48 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2022-06-14 16:44 [iptables PATCH] nft: Exit if nftnl_alloc_expr fails Phil Sutter
2022-06-15  7:04 ` Pablo Neira Ayuso
2022-06-15  8:47   ` Phil Sutter

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