Messages in this thread Patch in this message | | | From | Mickaël Salaün <> | Subject | [PATCH bpf-next v10 01/10] fs,security: Add a new file access type: MAY_CHROOT | Date | Sun, 21 Jul 2019 23:31:07 +0200 |
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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@digikod.net> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: James Morris <jmorris@namei.org> Cc: John Johansen <john.johansen@canonical.com> Cc: Kees Cook <keescook@chromium.org> Cc: Paul Moore <paul@paul-moore.com> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: linux-fsdevel@vger.kernel.org --- 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 b5b80469b93d..e8767318fd03 100644 --- a/fs/open.c +++ b/fs/open.c @@ -494,7 +494,8 @@ int ksys_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 75f2ed289a3f..7a0d92b1da85 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -99,6 +99,7 @@ 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 -- 2.22.0
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