From d2e4d593516e877f1f6fb40031eb495f36606e16 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 18 Oct 2016 00:05:30 +0200 Subject: [PATCH] netfilter: nf_tables: avoid uninitialized variable warning The newly added nft_range_eval() function handles the two possible nft range operations, but as the compiler warning points out, any unexpected value would lead to the 'mismatch' variable being used without being initialized: net/netfilter/nft_range.c: In function 'nft_range_eval': net/netfilter/nft_range.c:45:5: error: 'mismatch' may be used uninitialized in this function [-Werror=maybe-uninitialized] This removes the variable in question and instead moves the condition into the switch itself, which is potentially more efficient than adding a bogus 'default' clause as in my first approach, and is nicer than using the 'uninitialized_var' macro. Fixes: 0f3cd9b36977 ("netfilter: nf_tables: add range expression") Link: http://patchwork.ozlabs.org/patch/677114/ Signed-off-by: Arnd Bergmann Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_range.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/net/netfilter/nft_range.c b/net/netfilter/nft_range.c index 9bc4586c3006..fbc88009ca2e 100644 --- a/net/netfilter/nft_range.c +++ b/net/netfilter/nft_range.c @@ -28,22 +28,20 @@ static void nft_range_eval(const struct nft_expr *expr, const struct nft_pktinfo *pkt) { const struct nft_range_expr *priv = nft_expr_priv(expr); - bool mismatch; int d1, d2; d1 = memcmp(®s->data[priv->sreg], &priv->data_from, priv->len); d2 = memcmp(®s->data[priv->sreg], &priv->data_to, priv->len); switch (priv->op) { case NFT_RANGE_EQ: - mismatch = (d1 < 0 || d2 > 0); + if (d1 < 0 || d2 > 0) + regs->verdict.code = NFT_BREAK; break; case NFT_RANGE_NEQ: - mismatch = (d1 >= 0 && d2 <= 0); + if (d1 >= 0 && d2 <= 0) + regs->verdict.code = NFT_BREAK; break; } - - if (mismatch) - regs->verdict.code = NFT_BREAK; } static const struct nla_policy nft_range_policy[NFTA_RANGE_MAX + 1] = { -- 2.20.1