Re: [PATCH] CIPSO: Fix unaligned memory access in cipso_v4_gentag_hdr

On Thu, Mar 4, 2021 at 4:17 PM Ondrej Mosnacek [off-list ref] wrote:

On Thu, Mar 4, 2021 at 10:09 PM Seergey Nazarov [off-list ref] wrote:

quoted

We need to use put_unaligned when writing 32-bit DOI value
in cipso_v4_gentag_hdr to avoid unaligned memory access.

Signed-off-by: Sergey Nazarov <redacted>
---
 net/ipv4/cipso_ipv4.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index 471d33a..28dfe40 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c

@@ -1162,7 +1162,7 @@ static void cipso_v4_gentag_hdr(const struct

cipso_v4_doi *doi_def,
 {
        buf[0] = IPOPT_CIPSO;
        buf[1] = CIPSO_V4_HDR_LEN + len;
-       *(__be32 *)&buf[2] = htonl(doi_def->doi);
+       put_unaligned_be32(doi_def->doi, (__be32 *)&buf[2]);

I think you can now also drop the cast, since put_unaligned_be32()
expects a void *.

Yes, it shouldn't be necessary.

You should also send this to netdev as NetLabel code lives under net/
and goes to Linus via the netdev tree.

Also, looking at the code, there are a few similar spots you should
probably fix while you are revising this patch:

* the short/__be16 assignment in cipso_v4_map_cat_enum_hton()
* the short/__be16 assignments in cipso_v4_map_cat_rng_hton()
* the long/__be32 assignment in calipso_genopt()

-- 
paul moore
www.paul-moore.com