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 Signed-off-by: Sasha Levin sashal@kernel.org [Ajay: Modified to apply on v5.4.y] Signed-off-by: Ajay Kaher ajay.kaher@broadcom.com --- 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()));