[PATCH v1 30/42] NFSD: Update the NFSv2 SETATTR argument decoder to use struct xdr_stream

Chuck Lever
2021-01-05T15:32:38Z

fs/nfsd/nfsxdr.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 76 insertions(+), 6 deletions(-)

diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
index 3d0fe03a3fb9..6c87ea8f3876 100644
--- a/fs/nfsd/nfsxdr.c
+++ b/fs/nfsd/nfsxdr.c
@@ -173,6 +173,79 @@ decode_sattr(__be32 *p, struct iattr *iap, struct user_namespace *userns)
return p;
}

+static bool
+svcxdr_decode_sattr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
+ struct iattr *iap)
+{
+ u32 tmp1, tmp2;
+ __be32 *p;
+
+ p = xdr_inline_decode(xdr, XDR_UNIT * 8);
+ if (!p)
+ return false;
+
+ iap->ia_valid = 0;
+
+ /*
+ * Some Sun clients put 0xffff in the mode field when they
+ * mean 0xffffffff.
+ */
+ tmp1 = be32_to_cpup(p++);
+ if (tmp1 != (u32)-1 && tmp1 != 0xffff) {
+ iap->ia_valid |= ATTR_MODE;
+ iap->ia_mode = tmp1;
+ }
+
+ tmp1 = be32_to_cpup(p++);
+ if (tmp1 != (u32)-1) {
+ iap->ia_uid = make_kuid(nfsd_user_namespace(rqstp), tmp1);
+ if (uid_valid(iap->ia_uid))
+ iap->ia_valid |= ATTR_UID;
+ }
+
+ tmp1 = be32_to_cpup(p++);
+ if (tmp1 != (u32)-1) {
+ iap->ia_gid = make_kgid(nfsd_user_namespace(rqstp), tmp1);
+ if (gid_valid(iap->ia_gid))
+ iap->ia_valid |= ATTR_GID;
+ }
+
+ tmp1 = be32_to_cpup(p++);
+ if (tmp1 != (u32)-1) {
+ iap->ia_valid |= ATTR_SIZE;
+ iap->ia_size = tmp1;
+ }
+
+ tmp1 = be32_to_cpup(p++);
+ tmp2 = be32_to_cpup(p++);
+ if (tmp1 != (u32)-1 && tmp2 != (u32)-1) {
+ iap->ia_valid |= ATTR_ATIME | ATTR_ATIME_SET;
+ iap->ia_atime.tv_sec = tmp1;
+ iap->ia_atime.tv_nsec = tmp2 * NSEC_PER_USEC;
+ }
+
+ tmp1 = be32_to_cpup(p++);
+ tmp2 = be32_to_cpup(p++);
+ if (tmp1 != (u32)-1 && tmp2 != (u32)-1) {
+ iap->ia_valid |= ATTR_MTIME | ATTR_MTIME_SET;
+ iap->ia_mtime.tv_sec = tmp1;
+ iap->ia_mtime.tv_nsec = tmp2 * NSEC_PER_USEC;
+ /*
+ * Passing the invalid value useconds=1000000 for mtime
+ * is a Sun convention for "set both mtime and atime to
+ * current server time". It's needed to make permissions
+ * checks for the "touch" program across v2 mounts to
+ * Solaris and Irix boxes work correctly. See description of
+ * sattr in section 6.1 of "NFS Illustrated" by
+ * Brent Callaghan, Addison-Wesley, ISBN 0-201-32750-5
+ */
+ if (tmp2 == 1000000)
+ iap->ia_valid &= ~(ATTR_ATIME_SET|ATTR_MTIME_SET);
+ }
+
+ return true;
+}
+
static __be32 *
encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp,
struct kstat *stat)
@@ -253,14 +326,11 @@ nfssvc_decode_fhandleargs(struct svc_rqst *rqstp, __be32 *p)
int
nfssvc_decode_sattrargs(struct svc_rqst *rqstp, __be32 *p)
{
+ struct xdr_stream *xdr = &rqstp->rq_arg_stream;
struct nfsd_sattrargs *args = rqstp->rq_argp;

- p = decode_fh(p, &args->fh);
- if (!p)
- return 0;
- p = decode_sattr(p, &args->attrs, nfsd_user_namespace(rqstp));
-
- return xdr_argsize_check(rqstp, p);
+ return svcxdr_decode_fhandle(xdr, &args->fh) &&
+ svcxdr_decode_sattr(rqstp, xdr, &args->attrs);
}

int