xfs: sanity check inode mode when creating new dentry

The helper xfs_dentry_to_name() is used by 2 different
classes of callers: Callers that pass zero mode and don't care
about the returned name.type field and Callers that pass
non zero mode and do care about the name.type field.

Change xfs_dentry_to_name() to not take the mode argument and
change the call sites of the first class to not pass the mode
argument.

Create a new helper xfs_dentry_mode_to_name() which does pass
the mode argument and returns -EFSCORRUPTED if mode is invalid.
Callers that translate non zero mode to on-disk file type now
check the return value and will export the error to user instead
of staging an invalid file type to be written to directory entry.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 821f08d4e256d6403894bd070fe3701631117a91..22c16155f1b42a1380f85935fa43706cd60e2b40 100644 (file)
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -97,6 +97,16 @@ xfs_init_security(
 
 static void
 xfs_dentry_to_name(
+       struct xfs_name *namep,
+       struct dentry   *dentry)
+{
+       namep->name = dentry->d_name.name;
+       namep->len = dentry->d_name.len;
+       namep->type = XFS_DIR3_FT_UNKNOWN;
+}
+
+static int
+xfs_dentry_mode_to_name(
        struct xfs_name *namep,
        struct dentry   *dentry,
        int             mode)
@@ -104,6 +114,11 @@ xfs_dentry_to_name(
        namep->name = dentry->d_name.name;
        namep->len = dentry->d_name.len;
        namep->type = xfs_mode_to_ftype(mode);
+
+       if (unlikely(namep->type == XFS_DIR3_FT_UNKNOWN))
+               return -EFSCORRUPTED;
+
+       return 0;
 }
 
 STATIC void
@@ -119,7 +134,7 @@ xfs_cleanup_inode(
         * xfs_init_security we must back out.
         * ENOSPC can hit here, among other things.
         */
-       xfs_dentry_to_name(&teardown, dentry, 0);
+       xfs_dentry_to_name(&teardown, dentry);
 
        xfs_remove(XFS_I(dir), &teardown, XFS_I(inode));
 }
@@ -154,8 +169,12 @@ xfs_generic_create(
        if (error)
                return error;
 
+       /* Verify mode is valid also for tmpfile case */
+       error = xfs_dentry_mode_to_name(&name, dentry, mode);
+       if (unlikely(error))
+               goto out_free_acl;
+
        if (!tmpfile) {
-               xfs_dentry_to_name(&name, dentry, mode);
                error = xfs_create(XFS_I(dir), &name, mode, rdev, &ip);
        } else {
                error = xfs_create_tmpfile(XFS_I(dir), dentry, mode, &ip);
@@ -248,7 +267,7 @@ xfs_vn_lookup(
        if (dentry->d_name.len >= MAXNAMELEN)
                return ERR_PTR(-ENAMETOOLONG);
 
-       xfs_dentry_to_name(&name, dentry, 0);
+       xfs_dentry_to_name(&name, dentry);
        error = xfs_lookup(XFS_I(dir), &name, &cip, NULL);
        if (unlikely(error)) {
                if (unlikely(error != -ENOENT))
@@ -275,7 +294,7 @@ xfs_vn_ci_lookup(
        if (dentry->d_name.len >= MAXNAMELEN)
                return ERR_PTR(-ENAMETOOLONG);
 
-       xfs_dentry_to_name(&xname, dentry, 0);
+       xfs_dentry_to_name(&xname, dentry);
        error = xfs_lookup(XFS_I(dir), &xname, &ip, &ci_name);
        if (unlikely(error)) {
                if (unlikely(error != -ENOENT))
@@ -310,7 +329,9 @@ xfs_vn_link(
        struct xfs_name name;
        int             error;
 
-       xfs_dentry_to_name(&name, dentry, inode->i_mode);
+       error = xfs_dentry_mode_to_name(&name, dentry, inode->i_mode);
+       if (unlikely(error))
+               return error;
 
        error = xfs_link(XFS_I(dir), XFS_I(inode), &name);
        if (unlikely(error))
@@ -329,7 +350,7 @@ xfs_vn_unlink(
        struct xfs_name name;
        int             error;
 
-       xfs_dentry_to_name(&name, dentry, 0);
+       xfs_dentry_to_name(&name, dentry);
 
        error = xfs_remove(XFS_I(dir), &name, XFS_I(d_inode(dentry)));
        if (error)
@@ -359,7 +380,9 @@ xfs_vn_symlink(
 
        mode = S_IFLNK |
                (irix_symlink_mode ? 0777 & ~current_umask() : S_IRWXUGO);
-       xfs_dentry_to_name(&name, dentry, mode);
+       error = xfs_dentry_mode_to_name(&name, dentry, mode);
+       if (unlikely(error))
+               goto out;
 
        error = xfs_symlink(XFS_I(dir), &name, symname, mode, &cip);
        if (unlikely(error))
@@ -395,6 +418,7 @@ xfs_vn_rename(
 {
        struct inode    *new_inode = d_inode(ndentry);
        int             omode = 0;
+       int             error;
        struct xfs_name oname;
        struct xfs_name nname;
 
@@ -405,8 +429,14 @@ xfs_vn_rename(
        if (flags & RENAME_EXCHANGE)
                omode = d_inode(ndentry)->i_mode;
 
-       xfs_dentry_to_name(&oname, odentry, omode);
-       xfs_dentry_to_name(&nname, ndentry, d_inode(odentry)->i_mode);
+       error = xfs_dentry_mode_to_name(&oname, odentry, omode);
+       if (omode && unlikely(error))
+               return error;
+
+       error = xfs_dentry_mode_to_name(&nname, ndentry,
+                                       d_inode(odentry)->i_mode);
+       if (unlikely(error))
+               return error;
 
        return xfs_rename(XFS_I(odir), &oname, XFS_I(d_inode(odentry)),
                          XFS_I(ndir), &nname,