From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
commit c301f0981fdd3fd1ffac6836b423c4d7a8e0eb63 upstream.
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@xxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
[Ajay: Modified to apply on v5.4.y]
Signed-off-by: Ajay Kaher <ajay.kaher@xxxxxxxxxxxx>
---
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 0a49d44..cf314ce 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -130,9 +130,9 @@ static inline u16 nft_reg_load16(u32 *sreg)
return *(u16 *)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(u32 *sreg)
diff --git a/net/netfilter/nft_byteorder.c b/net/netfilter/nft_byteorder.c
index 7b0b8fe..9d250bd 100644
--- a/net/netfilter/nft_byteorder.c
+++ b/net/netfilter/nft_byteorder.c
@@ -38,20 +38,21 @@ 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], be64_to_cpu(src64));
+ nft_reg_store64(&dst64[i], be64_to_cpu(src64));
}
break;
case NFT_BYTEORDER_HTON:
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 ec2798f..ac7d3c7 100644
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -247,7 +247,7 @@ void nft_meta_get_eval(const struct nft_expr *expr,
strncpy((char *)dest, out->rtnl_link_ops->kind, IFNAMSIZ);
break;
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(ktime_get_real_seconds()));
--
2.7.4
