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Message-ID: <15fdceb5-2de5-4453-98b3-cfa9d486e8da@moroto.mountain>
Date: Fri, 3 Nov 2023 09:42:51 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: Florian Westphal <fw@...len.de>
Cc: Pablo Neira Ayuso <pablo@...filter.org>,
Jozsef Kadlecsik <kadlec@...filter.org>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
netfilter-devel@...r.kernel.org, coreteam@...filter.org,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
kernel-janitors@...r.kernel.org
Subject: [PATCH net] netfilter: nf_tables: fix pointer math issue in
nft_byteorder_eval()
The problem is in nft_byteorder_eval() where we are iterating through a
loop and writing to dst[0], dst[1], dst[2] and so on... On each
iteration we are writing 8 bytes. But dst[] is an array of u32 so each
element only has space for 4 bytes. That means that every iteration
overwrites part of the previous element.
I spotted this bug while reviewing commit caf3ef7468f7 ("netfilter:
nf_tables: prevent OOB access in nft_byteorder_eval") which is a related
issue. I think that the reason we have not detected this bug in testing
is that most of time we only write one element.
Fixes: ce1e7989d989 ("netfilter: nft_byteorder: provide 64bit le/be conversion")
Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
---
include/net/netfilter/nf_tables.h | 4 ++--
net/netfilter/nft_byteorder.c | 5 +++--
net/netfilter/nft_meta.c | 2 +-
3 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 3bbd13ab1ecf..b157c5cafd14 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -178,9 +178,9 @@ static inline __be32 nft_reg_load_be32(const u32 *sreg)
return *(__force __be32 *)sreg;
}
-static inline void nft_reg_store64(u32 *dreg, u64 val)
+static inline void nft_reg_store64(u64 *dreg, u64 val)
{
- put_unaligned(val, (u64 *)dreg);
+ put_unaligned(val, dreg);
}
static inline u64 nft_reg_load64(const u32 *sreg)
diff --git a/net/netfilter/nft_byteorder.c b/net/netfilter/nft_byteorder.c
index e596d1a842f7..f6e791a68101 100644
--- a/net/netfilter/nft_byteorder.c
+++ b/net/netfilter/nft_byteorder.c
@@ -38,13 +38,14 @@ void nft_byteorder_eval(const struct nft_expr *expr,
switch (priv->size) {
case 8: {
+ u64 *dst64 = (void *)dst;
u64 src64;
switch (priv->op) {
case NFT_BYTEORDER_NTOH:
for (i = 0; i < priv->len / 8; i++) {
src64 = nft_reg_load64(&src[i]);
- nft_reg_store64(&dst[i],
+ nft_reg_store64(&dst64[i],
be64_to_cpu((__force __be64)src64));
}
break;
@@ -52,7 +53,7 @@ void nft_byteorder_eval(const struct nft_expr *expr,
for (i = 0; i < priv->len / 8; i++) {
src64 = (__force __u64)
cpu_to_be64(nft_reg_load64(&src[i]));
- nft_reg_store64(&dst[i], src64);
+ nft_reg_store64(&dst64[i], src64);
}
break;
}
diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
index f7da7c43333b..ba0d3683a45d 100644
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -63,7 +63,7 @@ nft_meta_get_eval_time(enum nft_meta_keys key,
{
switch (key) {
case NFT_META_TIME_NS:
- nft_reg_store64(dest, ktime_get_real_ns());
+ nft_reg_store64((u64 *)dest, ktime_get_real_ns());
break;
case NFT_META_TIME_DAY:
nft_reg_store8(dest, nft_meta_weekday());
--
2.42.0
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