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 v4.19.y]
Signed-off-by: Ajay Kaher <ajay.kaher@xxxxxxxxxxxx>
---
net/netfilter/nft_byteorder.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/nft_byteorder.c b/net/netfilter/nft_byteorder.c
index dba1612..8c4ee49 100644
--- a/net/netfilter/nft_byteorder.c
+++ b/net/netfilter/nft_byteorder.c
@@ -41,19 +41,20 @@ static 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 = get_unaligned((u64 *)&src[i]);
- put_unaligned_be64(src64, &dst[i]);
+ put_unaligned_be64(src64, &dst64[i]);
}
break;
case NFT_BYTEORDER_HTON:
for (i = 0; i < priv->len / 8; i++) {
src64 = get_unaligned_be64(&src[i]);
- put_unaligned(src64, (u64 *)&dst[i]);
+ put_unaligned(src64, &dst64[i]);
}
break;
}
--
2.7.4
