[PATCH v1 32/42] NFSD: Update the NFSv2 SYMLINK argument decoder to use struct xdr_stream

Chuck Lever
2021-01-05T15:32:48Z

fs/nfsd/nfsxdr.c | 113 +++++-------------------------------------------------
1 file changed, 10 insertions(+), 103 deletions(-)

diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
index 2e2806cbe7b8..f2cb4794aeaf 100644
--- a/fs/nfsd/nfsxdr.c
+++ b/fs/nfsd/nfsxdr.c
@@ -66,26 +66,6 @@ encode_fh(__be32 *p, struct svc_fh *fhp)
return p + (NFS_FHSIZE>> 2);
}

-/*
- * Decode a file name and make sure that the path contains
- * no slashes or null bytes.
- */
-static __be32 *
-decode_filename(__be32 *p, char **namp, unsigned int *lenp)
-{
- char *name;
- unsigned int i;
-
- if ((p = xdr_decode_string_inplace(p, namp, lenp, NFS_MAXNAMLEN)) != NULL) {
- for (i = 0, name = *namp; i < *lenp; i++, name++) {
- if (*name == '\0' || *name == '/')
- return NULL;
- }
- }
-
- return p;
-}
-
static bool
svcxdr_decode_filename(struct xdr_stream *xdr, char **name, unsigned int *len)
{
@@ -118,61 +98,6 @@ svcxdr_decode_diropargs(struct xdr_stream *xdr, struct svc_fh *fhp,
svcxdr_decode_filename(xdr, name, len);
}

-static __be32 *
-decode_sattr(__be32 *p, struct iattr *iap, struct user_namespace *userns)
-{
- u32 tmp, tmp1;
-
- iap->ia_valid = 0;
-
- /* Sun client bug compatibility check: some sun clients seem to
- * put 0xffff in the mode field when they mean 0xffffffff.
- * Quoting the 4.4BSD nfs server code: Nah nah nah nah na nah.
- */
- if ((tmp = ntohl(*p++)) != (u32)-1 && tmp != 0xffff) {
- iap->ia_valid |= ATTR_MODE;
- iap->ia_mode = tmp;
- }
- if ((tmp = ntohl(*p++)) != (u32)-1) {
- iap->ia_uid = make_kuid(userns, tmp);
- if (uid_valid(iap->ia_uid))
- iap->ia_valid |= ATTR_UID;
- }
- if ((tmp = ntohl(*p++)) != (u32)-1) {
- iap->ia_gid = make_kgid(userns, tmp);
- if (gid_valid(iap->ia_gid))
- iap->ia_valid |= ATTR_GID;
- }
- if ((tmp = ntohl(*p++)) != (u32)-1) {
- iap->ia_valid |= ATTR_SIZE;
- iap->ia_size = tmp;
- }
- tmp = ntohl(*p++); tmp1 = ntohl(*p++);
- if (tmp != (u32)-1 && tmp1 != (u32)-1) {
- iap->ia_valid |= ATTR_ATIME | ATTR_ATIME_SET;
- iap->ia_atime.tv_sec = tmp;
- iap->ia_atime.tv_nsec = tmp1 * 1000;
- }
- tmp = ntohl(*p++); tmp1 = ntohl(*p++);
- if (tmp != (u32)-1 && tmp1 != (u32)-1) {
- iap->ia_valid |= ATTR_MTIME | ATTR_MTIME_SET;
- iap->ia_mtime.tv_sec = tmp;
- iap->ia_mtime.tv_nsec = tmp1 * 1000;
- /*
- * 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 (tmp1 == 1000000)
- iap->ia_valid &= ~(ATTR_ATIME_SET|ATTR_MTIME_SET);
- }
- return p;
-}
-
static bool
svcxdr_decode_sattr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
struct iattr *iap)
@@ -435,40 +360,22 @@ nfssvc_decode_linkargs(struct svc_rqst *rqstp, __be32 *p)
int
nfssvc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p)
{
+ struct xdr_stream *xdr = &rqstp->rq_arg_stream;
struct nfsd_symlinkargs *args = rqstp->rq_argp;
- char *base = (char *)p;
- size_t xdrlen;
+ struct kvec *head = rqstp->rq_arg.head;

- if ( !(p = decode_fh(p, &args->ffh))
- || !(p = decode_filename(p, &args->fname, &args->flen)))
+ if (!svcxdr_decode_diropargs(xdr, &args->ffh, &args->fname, &args->flen))
+ return 0;
+ if (xdr_stream_decode_u32(xdr, &args->tlen) < 0)
return 0;
-
- args->tlen = ntohl(*p++);
if (args->tlen == 0)
return 0;

- args->first.iov_base = p;
- args->first.iov_len = rqstp->rq_arg.head[0].iov_len;
- args->first.iov_len -= (char *)p - base;
-
- /* This request is never larger than a page. Therefore,
- * transport will deliver either:
- * 1. pathname in the pagelist -> sattr is in the tail.
- * 2. everything in the head buffer -> sattr is in the head.
- */
- if (rqstp->rq_arg.page_len) {
- if (args->tlen != rqstp->rq_arg.page_len)
- return 0;
- p = rqstp->rq_arg.tail[0].iov_base;
- } else {
- xdrlen = XDR_QUADLEN(args->tlen);
- if (xdrlen > args->first.iov_len - (8 * sizeof(__be32)))
- return 0;
- p += xdrlen;
- }
- decode_sattr(p, &args->attrs, nfsd_user_namespace(rqstp));
-
- return 1;
+ args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);
+ args->first.iov_base = xdr_inline_decode(xdr, args->tlen);
+ if (!args->first.iov_base)
+ return 0;
+ return svcxdr_decode_sattr(rqstp, xdr, &args->attrs);
}

int