security: filesystem capabilities: fix fragile setuid fixup code

This commit includes a bugfix for the fragile setuid fixup code in the
case that filesystem capabilities are supported (in access()).  The effect
of this fix is gated on filesystem capability support because changing
securebits is only supported when filesystem capabilities support is
configured.)

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrew G. Morgan 2008-07-04 09:59:58 -07:00 committed by Linus Torvalds
parent abbaeff38c
commit 086f7316f0
4 changed files with 53 additions and 22 deletions

View file

@ -7,14 +7,15 @@
inheritance of root-permissions and suid-root executable under
compatibility mode. We raise the effective and inheritable bitmasks
*of the executable file* if the effective uid of the new process is
0. If the real uid is 0, we raise the inheritable bitmask of the
0. If the real uid is 0, we raise the effective (legacy) bit of the
executable file. */
#define SECURE_NOROOT 0
#define SECURE_NOROOT_LOCKED 1 /* make bit-0 immutable */
/* When set, setuid to/from uid 0 does not trigger capability-"fixes"
to be compatible with old programs relying on set*uid to loose
privileges. When unset, setuid doesn't change privileges. */
/* When set, setuid to/from uid 0 does not trigger capability-"fixup".
When unset, to provide compatiblility with old programs relying on
set*uid to gain/lose privilege, transitions to/from uid 0 cause
capabilities to be gained/lost. */
#define SECURE_NO_SETUID_FIXUP 2
#define SECURE_NO_SETUID_FIXUP_LOCKED 3 /* make bit-2 immutable */
@ -26,10 +27,10 @@
#define SECURE_KEEP_CAPS 4
#define SECURE_KEEP_CAPS_LOCKED 5 /* make bit-4 immutable */
/* Each securesetting is implemented using two bits. One bit specify
/* Each securesetting is implemented using two bits. One bit specifies
whether the setting is on or off. The other bit specify whether the
setting is fixed or not. A setting which is fixed cannot be changed
from user-level. */
setting is locked or not. A setting which is locked cannot be
changed from user-level. */
#define issecure_mask(X) (1 << (X))
#define issecure(X) (issecure_mask(X) & current->securebits)