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nfsd: check d_can_lookup in fh_verify of directories

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Create and other nfsd ops generally assume we can call lookup_one_len on
inodes with S_IFDIR set.  Al says that this assumption isn't true in
general, though it should be for the filesystem objects nfsd sees.

Add a check just to make sure our assumption isn't violated.

Remove a couple checks for i_op->lookup in create code.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
J. Bruce Fields 2016-07-19 17:33:04 -04:00
parent 12391d0723
commit e75b23f9e3
2 changed files with 10 additions and 13 deletions
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14
fs/nfsd/nfsfh.c
View File

@ -59,14 +59,20 @@ static int nfsd_acceptable(void *expv, struct dentry *dentry)
* the write call).
*/
static inline __be32
nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, umode_t requested)
nfsd_mode_check(struct svc_rqst *rqstp, struct dentry *dentry,
umode_t requested)
{
mode &= S_IFMT;
umode_t mode = d_inode(dentry)->i_mode & S_IFMT;
if (requested == 0) /* the caller doesn't care */
return nfs_ok;
if (mode == requested)
if (mode == requested) {
if (mode == S_IFDIR && !d_can_lookup(dentry)) {
WARN_ON_ONCE(1);
return nfserr_notdir;
}
return nfs_ok;
}
/*
* v4 has an error more specific than err_notdir which we should
* return in preference to err_notdir:
@ -340,7 +346,7 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, int access)
if (error)
goto out;
error = nfsd_mode_check(rqstp, d_inode(dentry)->i_mode, type);
error = nfsd_mode_check(rqstp, dentry, type);
if (error)
goto out;

9
fs/nfsd/vfs.c
View File

@ -1169,9 +1169,6 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
dentry = fhp->fh_dentry;
dirp = d_inode(dentry);
err = nfserr_notdir;
if (!dirp->i_op->lookup)
goto out;
/*
* Check whether the response file handle has been verified yet.
* If it has, the parent directory should already be locked.
@ -1310,12 +1307,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
dentry = fhp->fh_dentry;
dirp = d_inode(dentry);
/* Get all the sanity checks out of the way before
* we lock the parent. */
err = nfserr_notdir;
if (!dirp->i_op->lookup)
goto out;
host_err = fh_want_write(fhp);
if (host_err)
goto out_nfserr;