diff options
Diffstat (limited to 'fs/nfsd/nfsfh.c')
| -rw-r--r-- | fs/nfsd/nfsfh.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c index 951938d6c495..44812c32e51e 100644 --- a/fs/nfsd/nfsfh.c +++ b/fs/nfsd/nfsfh.c @@ -103,6 +103,36 @@ static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp, return nfserrno(nfsd_setuser(rqstp, exp)); } +static inline __be32 check_pseudo_root(struct svc_rqst *rqstp, + struct dentry *dentry, struct svc_export *exp) +{ + if (!(exp->ex_flags & NFSEXP_V4ROOT)) + return nfs_ok; + /* + * v2/v3 clients have no need for the V4ROOT export--they use + * the mount protocl instead; also, further V4ROOT checks may be + * in v4-specific code, in which case v2/v3 clients could bypass + * them. + */ + if (!nfsd_v4client(rqstp)) + return nfserr_stale; + /* + * We're exposing only the directories and symlinks that have to be + * traversed on the way to real exports: + */ + if (unlikely(!S_ISDIR(dentry->d_inode->i_mode) && + !S_ISLNK(dentry->d_inode->i_mode))) + return nfserr_stale; + /* + * A pseudoroot export gives permission to access only one + * single directory; the kernel has to make another upcall + * before granting access to anything else under it: + */ + if (unlikely(dentry != exp->ex_path.dentry)) + return nfserr_stale; + return nfs_ok; +} + /* * Use the given filehandle to look up the corresponding export and * dentry. On success, the results are used to set fh_export and @@ -299,6 +329,10 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access) * (for example, if different id-squashing options are in * effect on the new filesystem). */ + error = check_pseudo_root(rqstp, dentry, exp); + if (error) + goto out; + error = nfsd_setuser_and_check_port(rqstp, exp); if (error) goto out; |