4.19-stable review patch. If anyone has any objections, please let me know.
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From: Dan Carpenter dan.carpenter@linaro.org
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@linaro.org Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org [Ajay: Modified to apply on v4.19.y] Signed-off-by: Ajay Kaher ajay.kaher@broadcom.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/netfilter/nft_byteorder.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/net/netfilter/nft_byteorder.c +++ b/net/netfilter/nft_byteorder.c @@ -41,19 +41,20 @@ static void nft_byteorder_eval(const str
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; }