netfilter: nf_osf: avoid passing pointer to local var (c165d57b) · Commits · 戴 / test

gcc-10 points out that a code path exists where a pointer to a stack variable may be passed back to the caller: net/netfilter/nfnetlink_osf.c: In function 'nf_osf_hdr_ctx_init': cc1: warning: function may return address of local variable [-Wreturn-local-addr] net/netfilter/nfnetlink_osf.c:171:16: note: declared here 171 | struct tcphdr _tcph; | ^~~~~ I am not sure whether this can happen in practice, but moving the variable declaration into the callers avoids the problem. Fixes: ("netfilter: nf_osf: add struct nf_osf_hdr_ctx") Signed-off-by:

Arnd Bergmann <arnd@arndb.de> Reviewed-by:

Florian Westphal <fw@strlen.de> Signed-off-by:

Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nfnetlink_osf.c

+7 −5

Original line number	Diff line number	Diff line
		@@ -165,12 +165,12 @@ static bool nf_osf_match_one(const struct sk_buff *skb,
		static const struct tcphdr nf_osf_hdr_ctx_init(struct nf_osf_hdr_ctx ctx,
		const struct sk_buff *skb,
		const struct iphdr *ip,
		unsigned char *opts)
		unsigned char *opts,
		struct tcphdr *_tcph)
		{
		const struct tcphdr *tcp;
		struct tcphdr _tcph;

		tcp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(struct tcphdr), &_tcph);
		tcp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(struct tcphdr), _tcph);
		if (!tcp)
		return NULL;

		@@ -205,10 +205,11 @@ nf_osf_match(const struct sk_buff *skb, u_int8_t family,
		int fmatch = FMATCH_WRONG;
		struct nf_osf_hdr_ctx ctx;
		const struct tcphdr *tcp;
		struct tcphdr _tcph;

		memset(&ctx, 0, sizeof(ctx));

		tcp = nf_osf_hdr_ctx_init(&ctx, skb, ip, opts);
		tcp = nf_osf_hdr_ctx_init(&ctx, skb, ip, opts, &_tcph);
		if (!tcp)
		return false;

		@@ -265,10 +266,11 @@ bool nf_osf_find(const struct sk_buff *skb,
		const struct nf_osf_finger *kf;
		struct nf_osf_hdr_ctx ctx;
		const struct tcphdr *tcp;
		struct tcphdr _tcph;

		memset(&ctx, 0, sizeof(ctx));

		tcp = nf_osf_hdr_ctx_init(&ctx, skb, ip, opts);
		tcp = nf_osf_hdr_ctx_init(&ctx, skb, ip, opts, &_tcph);
		if (!tcp)
		return false;

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