NFSD: fix endianness issue in nfsd4_encode_fattr4

The nfs4 mount fails with EIO on 64-bit big endian architectures since
v6.7. The issue arises from employing a union in the nfsd4_encode_fattr4()
function to overlay a 32-bit array with a 64-bit values based bitmap,
which does not function as intended. Address the endianness issue by
utilizing bitmap_from_arr32() to copy 32-bit attribute masks into a
bitmap in an endianness-agnostic manner.

Cc: stable@vger.kernel.org
Fixes: fce7913b13d0 ("NFSD: Use a bitmask loop to encode FATTR4 results")
Link: https://bugs.launchpad.net/ubuntu/+source/nfs-utils/+bug/2060217
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index fac938f563ad022ce79cdc5f67321bc7f529cc1c..1955481832e03796170ea8f80361bc25cc452ca6 100644 (file)
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3490,11 +3490,13 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
                    struct dentry *dentry, const u32 *bmval,
                    int ignore_crossmnt)
 {
+       DECLARE_BITMAP(attr_bitmap, ARRAY_SIZE(nfsd4_enc_fattr4_encode_ops));
        struct nfsd4_fattr_args args;
        struct svc_fh *tempfh = NULL;
        int starting_len = xdr->buf->len;
        __be32 *attrlen_p, status;
        int attrlen_offset;
+       u32 attrmask[3];
        int err;
        struct nfsd4_compoundres *resp = rqstp->rq_resp;
        u32 minorversion = resp->cstate.minorversion;
@@ -3502,10 +3504,6 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
                .mnt    = exp->ex_path.mnt,
                .dentry = dentry,
        };
-       union {
-               u32             attrmask[3];
-               unsigned long   mask[2];
-       } u;
        unsigned long bit;
        bool file_modified = false;
        u64 size = 0;
@@ -3521,20 +3519,19 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
        /*
         * Make a local copy of the attribute bitmap that can be modified.
         */
-       memset(&u, 0, sizeof(u));
-       u.attrmask[0] = bmval[0];
-       u.attrmask[1] = bmval[1];
-       u.attrmask[2] = bmval[2];
+       attrmask[0] = bmval[0];
+       attrmask[1] = bmval[1];
+       attrmask[2] = bmval[2];
 
        args.rdattr_err = 0;
        if (exp->ex_fslocs.migrated) {
-               status = fattr_handle_absent_fs(&u.attrmask[0], &u.attrmask[1],
-                                               &u.attrmask[2], &args.rdattr_err);
+               status = fattr_handle_absent_fs(&attrmask[0], &attrmask[1],
+                                               &attrmask[2], &args.rdattr_err);
                if (status)
                        goto out;
        }
        args.size = 0;
-       if (u.attrmask[0] & (FATTR4_WORD0_CHANGE | FATTR4_WORD0_SIZE)) {
+       if (attrmask[0] & (FATTR4_WORD0_CHANGE | FATTR4_WORD0_SIZE)) {
                status = nfsd4_deleg_getattr_conflict(rqstp, d_inode(dentry),
                                        &file_modified, &size);
                if (status)
@@ -3553,16 +3550,16 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
 
        if (!(args.stat.result_mask & STATX_BTIME))
                /* underlying FS does not offer btime so we can't share it */
-               u.attrmask[1] &= ~FATTR4_WORD1_TIME_CREATE;
-       if ((u.attrmask[0] & (FATTR4_WORD0_FILES_AVAIL | FATTR4_WORD0_FILES_FREE |
+               attrmask[1] &= ~FATTR4_WORD1_TIME_CREATE;
+       if ((attrmask[0] & (FATTR4_WORD0_FILES_AVAIL | FATTR4_WORD0_FILES_FREE |
                        FATTR4_WORD0_FILES_TOTAL | FATTR4_WORD0_MAXNAME)) ||
-           (u.attrmask[1] & (FATTR4_WORD1_SPACE_AVAIL | FATTR4_WORD1_SPACE_FREE |
+           (attrmask[1] & (FATTR4_WORD1_SPACE_AVAIL | FATTR4_WORD1_SPACE_FREE |
                       FATTR4_WORD1_SPACE_TOTAL))) {
                err = vfs_statfs(&path, &args.statfs);
                if (err)
                        goto out_nfserr;
        }
-       if ((u.attrmask[0] & (FATTR4_WORD0_FILEHANDLE | FATTR4_WORD0_FSID)) &&
+       if ((attrmask[0] & (FATTR4_WORD0_FILEHANDLE | FATTR4_WORD0_FSID)) &&
            !fhp) {
                tempfh = kmalloc(sizeof(struct svc_fh), GFP_KERNEL);
                status = nfserr_jukebox;
@@ -3577,10 +3574,10 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
                args.fhp = fhp;
 
        args.acl = NULL;
-       if (u.attrmask[0] & FATTR4_WORD0_ACL) {
+       if (attrmask[0] & FATTR4_WORD0_ACL) {
                err = nfsd4_get_nfs4_acl(rqstp, dentry, &args.acl);
                if (err == -EOPNOTSUPP)
-                       u.attrmask[0] &= ~FATTR4_WORD0_ACL;
+                       attrmask[0] &= ~FATTR4_WORD0_ACL;
                else if (err == -EINVAL) {
                        status = nfserr_attrnotsupp;
                        goto out;
@@ -3592,17 +3589,17 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
 
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
        args.context = NULL;
-       if ((u.attrmask[2] & FATTR4_WORD2_SECURITY_LABEL) ||
-            u.attrmask[0] & FATTR4_WORD0_SUPPORTED_ATTRS) {
+       if ((attrmask[2] & FATTR4_WORD2_SECURITY_LABEL) ||
+            attrmask[0] & FATTR4_WORD0_SUPPORTED_ATTRS) {
                if (exp->ex_flags & NFSEXP_SECURITY_LABEL)
                        err = security_inode_getsecctx(d_inode(dentry),
                                                &args.context, &args.contextlen);
                else
                        err = -EOPNOTSUPP;
                args.contextsupport = (err == 0);
-               if (u.attrmask[2] & FATTR4_WORD2_SECURITY_LABEL) {
+               if (attrmask[2] & FATTR4_WORD2_SECURITY_LABEL) {
                        if (err == -EOPNOTSUPP)
-                               u.attrmask[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
+                               attrmask[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
                        else if (err)
                                goto out_nfserr;
                }
@@ -3610,8 +3607,8 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
 #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
 
        /* attrmask */
-       status = nfsd4_encode_bitmap4(xdr, u.attrmask[0],
-                                     u.attrmask[1], u.attrmask[2]);
+       status = nfsd4_encode_bitmap4(xdr, attrmask[0], attrmask[1],
+                                     attrmask[2]);
        if (status)
                goto out;
 
@@ -3620,7 +3617,9 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
        attrlen_p = xdr_reserve_space(xdr, XDR_UNIT);
        if (!attrlen_p)
                goto out_resource;
-       for_each_set_bit(bit, (const unsigned long *)&u.mask,
+       bitmap_from_arr32(attr_bitmap, attrmask,
+                         ARRAY_SIZE(nfsd4_enc_fattr4_encode_ops));
+       for_each_set_bit(bit, attr_bitmap,
                         ARRAY_SIZE(nfsd4_enc_fattr4_encode_ops)) {
                status = nfsd4_enc_fattr4_encode_ops[bit](xdr, &args);
                if (status != nfs_ok)