2022-05-19 09:52:51

by David Howells

Subject: [PATCH] nfs: Fix fscache volume key rendering for endianness

Fix fscache volume key rendering for endianness. Convert the BE numbers in
the address to host-endian before printing them so that they're consistent
if the cache is copied between architectures.

Question: This change could lead to misidentification of a volume directory
in the cache on a LE machine (it's unlikely because the port number as well
as the address numbers all get flipped), but it was introduced in -rc1 in
this cycle so probably isn't in any distro kernels yet. Should I add a
version number to enforce non-matching?

Signed-off-by: David Howells <[email protected]>
cc: Dave Wysochanski <[email protected]>
cc: Trond Myklebust <[email protected]>
cc: Anna Schumaker <[email protected]>
cc: Jeff Layton <[email protected]>
cc: [email protected]
cc: [email protected]
---

fs/nfs/fscache.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index f73c09a9cf0a..0e5572b192b2 100644
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -54,17 +54,17 @@ static bool nfs_fscache_get_client_key(struct nfs_client *clp,

switch (clp->cl_addr.ss_family) {
case AF_INET:
- if (!nfs_append_int(key, _len, sin->sin_port) ||
- !nfs_append_int(key, _len, sin->sin_addr.s_addr))
+ if (!nfs_append_int(key, _len, ntohs(sin->sin_port)) ||
+ !nfs_append_int(key, _len, ntohl(sin->sin_addr.s_addr)))
return false;
return true;

case AF_INET6:
- if (!nfs_append_int(key, _len, sin6->sin6_port) ||
- !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[0]) ||
- !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[1]) ||
- !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[2]) ||
- !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[3]))
+ if (!nfs_append_int(key, _len, ntohs(sin6->sin6_port)) ||
+ !nfs_append_int(key, _len, ntohl(sin6->sin6_addr.s6_addr32[0])) ||
+ !nfs_append_int(key, _len, ntohl(sin6->sin6_addr.s6_addr32[1])) ||
+ !nfs_append_int(key, _len, ntohl(sin6->sin6_addr.s6_addr32[2])) ||
+ !nfs_append_int(key, _len, ntohl(sin6->sin6_addr.s6_addr32[3])))
return false;
return true;

2022-05-19 22:15:08

by David Howells

Subject: Re: [PATCH] nfs: Fix fscache volume key rendering for endianness

David Wysochanski <[email protected]> wrote:

> Did someone report the "cache copied between architectures" issue, or
> is that mostly a theoretical problem you noticed?

Ah, I didn't mention. Checker noticed it (make C=1).

David

2022-05-20 03:19:24

by David Wysochanski

Subject: Re: [PATCH] nfs: Fix fscache volume key rendering for endianness

On Thu, May 19, 2022 at 3:51 AM David Howells <[email protected]> wrote:
>
> Fix fscache volume key rendering for endianness. Convert the BE numbers in
> the address to host-endian before printing them so that they're consistent
> if the cache is copied between architectures.
>
> Question: This change could lead to misidentification of a volume directory
> in the cache on a LE machine (it's unlikely because the port number as well
> as the address numbers all get flipped), but it was introduced in -rc1 in
> this cycle so probably isn't in any distro kernels yet. Should I add a
> version number to enforce non-matching?
>
> Signed-off-by: David Howells <[email protected]>
> cc: Dave Wysochanski <[email protected]>
> cc: Trond Myklebust <[email protected]>
> cc: Anna Schumaker <[email protected]>
> cc: Jeff Layton <[email protected]>
> cc: [email protected]
> cc: [email protected]
> ---
>
> fs/nfs/fscache.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
> index f73c09a9cf0a..0e5572b192b2 100644
> --- a/fs/nfs/fscache.c
> +++ b/fs/nfs/fscache.c
> @@ -54,17 +54,17 @@ static bool nfs_fscache_get_client_key(struct nfs_client *clp,
>
> switch (clp->cl_addr.ss_family) {
> case AF_INET:
> - if (!nfs_append_int(key, _len, sin->sin_port) ||
> - !nfs_append_int(key, _len, sin->sin_addr.s_addr))
> + if (!nfs_append_int(key, _len, ntohs(sin->sin_port)) ||
> + !nfs_append_int(key, _len, ntohl(sin->sin_addr.s_addr)))
> return false;
> return true;
>
> case AF_INET6:
> - if (!nfs_append_int(key, _len, sin6->sin6_port) ||
> - !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[0]) ||
> - !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[1]) ||
> - !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[2]) ||
> - !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[3]))
> + if (!nfs_append_int(key, _len, ntohs(sin6->sin6_port)) ||
> + !nfs_append_int(key, _len, ntohl(sin6->sin6_addr.s6_addr32[0])) ||
> + !nfs_append_int(key, _len, ntohl(sin6->sin6_addr.s6_addr32[1])) ||
> + !nfs_append_int(key, _len, ntohl(sin6->sin6_addr.s6_addr32[2])) ||
> + !nfs_append_int(key, _len, ntohl(sin6->sin6_addr.s6_addr32[3])))
> return false;
> return true;
>
>
>

IMO it's not worth versioning in this case but I agree with this change.
Did someone report the "cache copied between architectures" issue, or
is that mostly a theoretical problem you noticed?

Acked-by: Dave Wysochanski <[email protected]>