Thanks Acked-By: Andrew G. Morgan <morgan@xxxxxxxxxx> On Sat, May 23, 2015 at 12:45 PM, Serge E. Hallyn <serge@xxxxxxxxxx> wrote: > On Thu, May 14, 2015 at 11:39:49PM -0700, Andy Lutomirski wrote: >> Per Andrew Morgan's request, add a securebit to allow admins to >> disable PR_CAP_AMBIENT_RAISE. This securebit will prevent processes >> from adding capabilities to their ambient set. >> >> For simplicity, this disables PR_CAP_AMBIENT_RAISE entirely rather >> than just disabling setting previously cleared bits. >> >> Requested-by: Andrew G. Morgan <morgan@xxxxxxxxxx> >> Cc: Kees Cook <keescook@xxxxxxxxxxxx> >> Cc: Christoph Lameter <cl@xxxxxxxxx> >> Cc: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx> >> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> >> Cc: Jonathan Corbet <corbet@xxxxxxx> >> Cc: Aaron Jones <aaronmdjones@xxxxxxxxx> >> CC: Ted Ts'o <tytso@xxxxxxx> >> Cc: linux-security-module@xxxxxxxxxxxxxxx >> Cc: linux-kernel@xxxxxxxxxxxxxxx >> Cc: linux-api@xxxxxxxxxxxxxxx >> Cc: akpm@xxxxxxxxxxxxxxxxxxx >> Cc: Andrew G. Morgan <morgan@xxxxxxxxxx> >> Cc: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx> >> Cc: Austin S Hemmelgarn <ahferroin7@xxxxxxxxx> >> Cc: Markku Savela <msa@xxxxxxxxxxx> >> Cc: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx> >> Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxx> >> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx> > > Interesting - at first I thought this wouldn't please Andrew as he'd > want the inverse, but I guess this way keeps the pure-capabilities > mode (with SECURE_ALL_BITS set) ambient-free which I suppose is > really the important thing. > > Acked-by: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx> > >> --- >> include/uapi/linux/securebits.h | 11 ++++++++++- >> security/commoncap.c | 3 ++- >> 2 files changed, 12 insertions(+), 2 deletions(-) >> >> diff --git a/include/uapi/linux/securebits.h b/include/uapi/linux/securebits.h >> index 985aac9e6bf8..35ac35cef217 100644 >> --- a/include/uapi/linux/securebits.h >> +++ b/include/uapi/linux/securebits.h >> @@ -43,9 +43,18 @@ >> #define SECBIT_KEEP_CAPS (issecure_mask(SECURE_KEEP_CAPS)) >> #define SECBIT_KEEP_CAPS_LOCKED (issecure_mask(SECURE_KEEP_CAPS_LOCKED)) >> >> +/* When set, a process cannot add new capabilities to its ambient set. */ >> +#define SECURE_NO_CAP_AMBIENT_RAISE 6 >> +#define SECURE_NO_CAP_AMBIENT_RAISE_LOCKED 7 /* make bit-6 immutable */ >> + >> +#define SECBIT_NO_CAP_AMBIENT_RAISE (issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE)) >> +#define SECBIT_NO_CAP_AMBIENT_RAISE_LOCKED \ >> + (issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE_LOCKED)) >> + >> #define SECURE_ALL_BITS (issecure_mask(SECURE_NOROOT) | \ >> issecure_mask(SECURE_NO_SETUID_FIXUP) | \ >> - issecure_mask(SECURE_KEEP_CAPS)) >> + issecure_mask(SECURE_KEEP_CAPS) | \ >> + issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE)) >> #define SECURE_ALL_LOCKS (SECURE_ALL_BITS << 1) >> >> #endif /* _UAPI_LINUX_SECUREBITS_H */ >> diff --git a/security/commoncap.c b/security/commoncap.c >> index 09541a6a85a0..98aa1b129c12 100644 >> --- a/security/commoncap.c >> +++ b/security/commoncap.c >> @@ -983,7 +983,8 @@ int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3, >> if (arg2 == PR_CAP_AMBIENT_RAISE && >> (!cap_raised(current_cred()->cap_permitted, arg3) || >> !cap_raised(current_cred()->cap_inheritable, >> - arg3))) >> + arg3) || >> + issecure(SECURE_NO_CAP_AMBIENT_RAISE))) >> return -EPERM; >> >> new = prepare_creds(); >> -- >> 2.1.0 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
