Re: [PATCH v2 libnftnl] Check all strdup

[Pablo Neira Ayuso <pablo@netfilter.org>]

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On Tue, Jun 07, 2016 at 05:08:10PM +0200, Pablo Neira Ayuso wrote:
> Carlos,
> 
> On Tue, May 31, 2016 at 12:08:32PM +0200, Carlos Falgueras García wrote:
> > Check all strdup possible error and treat it consequently.
> 
> Please, manually apply these two patches in your local working copy:
> 
> http://patchwork.ozlabs.org/patch/631659/
> http://patchwork.ozlabs.org/patch/631660/
> 
> Then, continue with the patch that I'm attaching.
> 
> As you can see, the idea is to return an integer for _set_data() and
> _set_str(), so the caller can check if the internal string allocation
> that the library performs has failed.

Forgot attachment, this is what I'm requesting you to continue.

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diff --git a/include/libnftnl/chain.h b/include/libnftnl/chain.h
index 954b39f..ed21e48 100644
--- a/include/libnftnl/chain.h
+++ b/include/libnftnl/chain.h
@@ -37,13 +37,13 @@ enum nftnl_chain_attr {
 bool nftnl_chain_is_set(const struct nftnl_chain *c, uint16_t attr);
 void nftnl_chain_unset(struct nftnl_chain *c, uint16_t attr);
 void nftnl_chain_set(struct nftnl_chain *t, uint16_t attr, const void *data);
-void nftnl_chain_set_data(struct nftnl_chain *t, uint16_t attr,
+int nftnl_chain_set_data(struct nftnl_chain *t, uint16_t attr,
 			     const void *data, uint32_t data_len);
 void nftnl_chain_set_u8(struct nftnl_chain *t, uint16_t attr, uint8_t data);
 void nftnl_chain_set_u32(struct nftnl_chain *t, uint16_t attr, uint32_t data);
 void nftnl_chain_set_s32(struct nftnl_chain *t, uint16_t attr, int32_t data);
 void nftnl_chain_set_u64(struct nftnl_chain *t, uint16_t attr, uint64_t data);
-void nftnl_chain_set_str(struct nftnl_chain *t, uint16_t attr, const char *str);
+int nftnl_chain_set_str(struct nftnl_chain *t, uint16_t attr, const char *str);
 
 const void *nftnl_chain_get(const struct nftnl_chain *c, uint16_t attr);
 const void *nftnl_chain_get_data(const struct nftnl_chain *c, uint16_t attr,
diff --git a/src/chain.c b/src/chain.c
index 70daaf3..75ab840 100644
--- a/src/chain.c
+++ b/src/chain.c
@@ -165,11 +165,13 @@ static uint32_t nftnl_chain_validate[NFTNL_CHAIN_MAX + 1] = {
 	[NFTNL_CHAIN_FAMILY]		= sizeof(uint32_t),
 };
 
-void nftnl_chain_set_data(struct nftnl_chain *c, uint16_t attr,
-			     const void *data, uint32_t data_len)
+int nftnl_chain_set_data(struct nftnl_chain *c, uint16_t attr,
+			 const void *data, uint32_t data_len)
 {
-	if (attr > NFTNL_CHAIN_MAX)
-		return;
+	if (attr > NFTNL_CHAIN_MAX) {
+		errno = -EOPNOTSUPP;
+		return -1;
+	}
 
 	nftnl_assert_validate(data, nftnl_chain_validate, attr, data_len);
 
@@ -182,6 +184,8 @@ void nftnl_chain_set_data(struct nftnl_chain *c, uint16_t attr,
 			xfree(c->table);
 
 		c->table = strdup(data);
+		if (!c->table)
+			return -1;
 		break;
 	case NFTNL_CHAIN_HOOKNUM:
 		memcpy(&c->hooknum, data, sizeof(c->hooknum));
@@ -212,15 +216,20 @@ void nftnl_chain_set_data(struct nftnl_chain *c, uint16_t attr,
 			xfree(c->type);
 
 		c->type = strdup(data);
+		if (!c->type)
+			return -1;
 		break;
 	case NFTNL_CHAIN_DEV:
 		if (c->dev)
 			xfree(c->dev);
 
 		c->dev = strdup(data);
+		if (!c->type)
+			return -1;
 		break;
 	}
 	c->flags |= (1 << attr);
+	return 0;
 }
 EXPORT_SYMBOL(nftnl_chain_set_data);
 
@@ -254,9 +263,9 @@ void nftnl_chain_set_u8(struct nftnl_chain *c, uint16_t attr, uint8_t data)
 }
 EXPORT_SYMBOL(nftnl_chain_set_u8);
 
-void nftnl_chain_set_str(struct nftnl_chain *c, uint16_t attr, const char *str)
+int nftnl_chain_set_str(struct nftnl_chain *c, uint16_t attr, const char *str)
 {
-	nftnl_chain_set_data(c, attr, str, strlen(str));
+	return nftnl_chain_set_data(c, attr, str, strlen(str));
 }
 EXPORT_SYMBOL(nftnl_chain_set_str);