Commit 6cdccdff authored Jan 21, 2024 by Dan Carpenter Committed by Liu Jian Jan 21, 2024

netfilter: nf_tables: fix pointer math issue in nft_byteorder_eval()

mainline inclusion
from mainline-v6.7-rc2
commit c301f0981fdd3fd1ffac6836b423c4d7a8e0eb63
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I8WQRG
CVE: CVE-2024-0607

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c301f0981fdd3fd1ffac6836b423c4d7a8e0eb63



---------------------------

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 caf3ef74 ("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: ce1e7989 ("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: Liu Jian <liujian56@huawei.com>

Conflicts:
	include/net/netfilter/nf_tables.h
	net/netfilter/nft_byteorder.c
	net/netfilter/nft_meta.c

parent 0d29fbb6

net/netfilter/nft_byteorder.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -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, (u64 *)&dst64[i]);
		}
		break;
		}