[ Upstream commit ed9b25d1970a4787ac6a39c2091e63b127ecbfc1 ]
Namespaced file capabilities were introduced in 8db6c34f1dbc .
When userspace reads an xattr for a namespaced capability, a
virtualized representation of it is returned if the caller is
in a user namespace owned by the capability's owning rootid.
The function which performs this virtualization was not hooked
up if CONFIG_SECURITY=n. Therefore in that case the original
xattr was shown instead of the virtualized one.
To test this using libcap-bin (*1),
$ v=$(mktemp)
$ unshare -Ur setcap cap_sys_admin-eip $v
$ unshare -Ur setcap -v cap_sys_admin-eip $v
/tmp/tmp.lSiIFRvt8Y: OK
"setcap -v" verifies the values instead of setting them, and
will check whether the rootid value is set. Therefore, with
this bug un-fixed, and with CONFIG_SECURITY=n, setcap -v will
fail:
$ v=$(mktemp)
$ unshare -Ur setcap cap_sys_admin=eip $v
$ unshare -Ur setcap -v cap_sys_admin=eip $v
nsowner[got=1000, want=0],/tmp/tmp.HHDiOOl9fY differs in []
Fix this bug by calling cap_inode_getsecurity() in
security_inode_getsecurity() instead of returning
-EOPNOTSUPP, when CONFIG_SECURITY=n.
*1 - note, if libcap is too old for getcap to have the '-n'
option, then use verify-caps instead.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=209689
Cc: Hervé Guillemet <herve@guillemet.org>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Serge Hallyn <shallyn@cisco.com>
Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 69393cb03ccdf29f3b452d3482ef918469d1c098 ]
Xmon should be either fully or partially disabled depending on the
kernel lockdown state.
Put xmon into read-only mode for lockdown=integrity and prevent user
entry into xmon when lockdown=confidentiality. Xmon checks the lockdown
state on every attempted entry:
(1) during early xmon'ing
(2) when triggered via sysrq
(3) when toggled via debugfs
(4) when triggered via a previously enabled breakpoint
The following lockdown state transitions are handled:
(1) lockdown=none -> lockdown=integrity
set xmon read-only mode
(2) lockdown=none -> lockdown=confidentiality
clear all breakpoints, set xmon read-only mode,
prevent user re-entry into xmon
(3) lockdown=integrity -> lockdown=confidentiality
clear all breakpoints, set xmon read-only mode,
prevent user re-entry into xmon
Suggested-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Christopher M. Riedl <cmr@informatik.wtf>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190907061124.1947-3-cmr@informatik.wtf
Signed-off-by: Sasha Levin <sashal@kernel.org>
Serge Hallyn