For compatibility reason, MAY_CHROOT is always set with MAY_CHDIR. However, this new flag enable to differentiate a chdir form a chroot. This is needed for the Landlock LSM to be able to evaluate a new root directory. Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxx> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Casey Schaufler <casey@xxxxxxxxxxxxxxxx> Cc: James Morris <jmorris@xxxxxxxxx> Cc: John Johansen <john.johansen@xxxxxxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Paul Moore <paul@xxxxxxxxxxxxxx> Cc: "Serge E. Hallyn" <serge@xxxxxxxxxx> Cc: Stephen Smalley <sds@xxxxxxxxxxxxx> Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Cc: linux-fsdevel@xxxxxxxxxxxxxxx --- fs/open.c | 3 ++- include/linux/fs.h | 1 + 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/open.c b/fs/open.c index 7ea118471dce..084d147c0e96 100644 --- a/fs/open.c +++ b/fs/open.c @@ -489,7 +489,8 @@ SYSCALL_DEFINE1(chroot, const char __user *, filename) if (error) goto out; - error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR); + error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR | + MAY_CHROOT); if (error) goto dput_and_out; diff --git a/include/linux/fs.h b/include/linux/fs.h index 2a815560fda0..67c62374446c 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -90,6 +90,7 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset, #define MAY_CHDIR 0x00000040 /* called from RCU mode, don't block */ #define MAY_NOT_BLOCK 0x00000080 +#define MAY_CHROOT 0x00000100 /* * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond -- 2.16.2
