2023-08-09 02:12:01

by Justin Stitt

Subject: [PATCH v2 5/7] netfilter: nft_osf: refactor deprecated strncpy

Use `strscpy_pad` over `strncpy` for NUL-terminated strings.

We can also drop the + 1 from `NFT_OSF_MAXGENRELEN + 1` since `strscpy`
will guarantee NUL-termination.

Signed-off-by: Justin Stitt <[email protected]>

---
Note: Should this usage @8556bceb9c409 also be changed to `strscpy_pad`
or is zero-padding not required here?
---
net/netfilter/nft_osf.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/netfilter/nft_osf.c b/net/netfilter/nft_osf.c
index 70820c66b591..7f61506e5b44 100644
--- a/net/netfilter/nft_osf.c
+++ b/net/netfilter/nft_osf.c
@@ -23,7 +23,7 @@ static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs,
struct nft_osf *priv = nft_expr_priv(expr);
u32 *dest = &regs->data[priv->dreg];
struct sk_buff *skb = pkt->skb;
- char os_match[NFT_OSF_MAXGENRELEN + 1];
+ char os_match[NFT_OSF_MAXGENRELEN];
const struct tcphdr *tcp;
struct nf_osf_data data;
struct tcphdr _tcph;
@@ -45,7 +45,7 @@ static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs,
}

if (!nf_osf_find(skb, nf_osf_fingers, priv->ttl, &data)) {
- strncpy((char *)dest, "unknown", NFT_OSF_MAXGENRELEN);
+ strscpy_pad((char *)dest, "unknown", NFT_OSF_MAXGENRELEN);
} else {
if (priv->flags & NFT_OSF_F_VERSION)
snprintf(os_match, NFT_OSF_MAXGENRELEN, "%s:%s",
@@ -53,7 +53,7 @@ static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs,
else
strscpy(os_match, data.genre, NFT_OSF_MAXGENRELEN);

- strncpy((char *)dest, os_match, NFT_OSF_MAXGENRELEN);
+ strscpy_pad((char *)dest, os_match, NFT_OSF_MAXGENRELEN);
}
}


--
2.41.0.640.ga95def55d0-goog

2023-08-09 21:27:50

by Florian Westphal

Subject: Re: [PATCH v2 5/7] netfilter: nft_osf: refactor deprecated strncpy

Justin Stitt <[email protected]> wrote:
---
> Note: Should this usage @8556bceb9c409 also be changed to `strscpy_pad`
> or is zero-padding not required here?

That commit converted strlcpy which doesn't do any zero-padding,
I don't see anything wrong with that change.