merged into cifs-2.6.git for-next and added cc: stable
On Tue, Aug 22, 2017 at 11:48 PM, Ronnie Sahlberg <lsahlber@xxxxxxxxxx> wrote:
> Add checking for the path component length and verify it is <= the maximum
> that the server advertizes via FileFsAttributeInformation.
>
> With this patch cifs.ko will now return ENAMETOOLONG instead of ENOENT
> when users to access an overlong path.
>
> To test this, try to cd into a (non-existing) directory on a CIFS share
> that has a too long name:
> cd /mnt/aaaaaaaaaaaaaaa...
>
> and it now should show a good error message from the shell:
> bash: cd: /mnt/aaaaaaaaaaaaaaaa...aaaaaa: File name too long
>
> rh bz 1153996
>
> Signed-off-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
> ---
> fs/cifs/dir.c | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
> index 56366e984076..569d3fb736be 100644
> --- a/fs/cifs/dir.c
> +++ b/fs/cifs/dir.c
> @@ -194,15 +194,20 @@ build_path_from_dentry_optional_prefix(struct dentry *direntry, bool prefix)
> }
>
> /*
> + * Don't allow path components longer than the server max.
> * Don't allow the separator character in a path component.
> * The VFS will not allow "/", but "\" is allowed by posix.
> */
> static int
> -check_name(struct dentry *direntry)
> +check_name(struct dentry *direntry, struct cifs_tcon *tcon)
> {
> struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
> int i;
>
> + if (unlikely(direntry->d_name.len >
> + tcon->fsAttrInfo.MaxPathNameComponentLength))
> + return -ENAMETOOLONG;
> +
> if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)) {
> for (i = 0; i < direntry->d_name.len; i++) {
> if (direntry->d_name.name[i] == '\\') {
> @@ -500,10 +505,6 @@ cifs_atomic_open(struct inode *inode, struct dentry *direntry,
> return finish_no_open(file, res);
> }
>
> - rc = check_name(direntry);
> - if (rc)
> - return rc;
> -
> xid = get_xid();
>
> cifs_dbg(FYI, "parent inode = 0x%p name is: %pd and dentry = 0x%p\n",
> @@ -516,6 +517,11 @@ cifs_atomic_open(struct inode *inode, struct dentry *direntry,
> }
>
> tcon = tlink_tcon(tlink);
> +
> + rc = check_name(direntry, tcon);
> + if (rc)
> + goto out_free_xid;
> +
> server = tcon->ses->server;
>
> if (server->ops->new_lease_key)
> @@ -776,7 +782,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
> }
> pTcon = tlink_tcon(tlink);
>
> - rc = check_name(direntry);
> + rc = check_name(direntry, pTcon);
> if (rc)
> goto lookup_out;
>
> --
> 2.13.3
>
--
Thanks,
Steve
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