2 Commits

Author	SHA1	Message	Date
Arnd Bergmann	7bba39ae52	apparmor: initialized returned struct aa_perms ... gcc-4.4 points out suspicious code in compute_mnt_perms, where the aa_perms structure is only partially initialized before getting returned: security/apparmor/mount.c: In function 'compute_mnt_perms': security/apparmor/mount.c:227: error: 'perms.prompt' is used uninitialized in this function security/apparmor/mount.c:227: error: 'perms.hide' is used uninitialized in this function security/apparmor/mount.c:227: error: 'perms.cond' is used uninitialized in this function security/apparmor/mount.c:227: error: 'perms.complain' is used uninitialized in this function security/apparmor/mount.c:227: error: 'perms.stop' is used uninitialized in this function security/apparmor/mount.c:227: error: 'perms.deny' is used uninitialized in this function Returning or assigning partially initialized structures is a bit tricky, in particular it is explicitly allowed in c99 to assign a partially initialized structure to another, as long as only members are read that have been initialized earlier. Looking at what various compilers do here, the version that produced the warning copied uninitialized stack data, while newer versions (and also clang) either set the other members to zero or don't update the parts of the return buffer that are not modified in the temporary structure, but they never warn about this. In case of apparmor, it seems better to be a little safer and always initialize the aa_perms structure. Most users already do that, this changes the remaining ones, including the one instance that I got the warning for. Fixes: fa488437d0f9 ("apparmor: add mount mediation") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Seth Arnold <seth.arnold@canonical.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: John Johansen <john.johansen@canonical.com>	2017-11-21 02:15:50 -08:00
John Johansen	2ea3ffb778	apparmor: add mount mediation ... Add basic mount mediation. That allows controlling based on basic mount parameters. It does not include special mount parameters for apparmor, super block labeling, or any triggers for apparmor namespace parameter modifications on pivot root. default userspace policy rules have the form of MOUNT RULE = ( MOUNT | REMOUNT | UMOUNT ) MOUNT = [ QUALIFIERS ] 'mount' [ MOUNT CONDITIONS ] [ SOURCE FILEGLOB ] [ '->' MOUNTPOINT FILEGLOB ] REMOUNT = [ QUALIFIERS ] 'remount' [ MOUNT CONDITIONS ] MOUNTPOINT FILEGLOB UMOUNT = [ QUALIFIERS ] 'umount' [ MOUNT CONDITIONS ] MOUNTPOINT FILEGLOB MOUNT CONDITIONS = [ ( 'fstype' | 'vfstype' ) ( '=' | 'in' ) MOUNT FSTYPE EXPRESSION ] [ 'options' ( '=' | 'in' ) MOUNT FLAGS EXPRESSION ] MOUNT FSTYPE EXPRESSION = ( MOUNT FSTYPE LIST | MOUNT EXPRESSION ) MOUNT FSTYPE LIST = Comma separated list of valid filesystem and virtual filesystem types (eg ext4, debugfs, etc) MOUNT FLAGS EXPRESSION = ( MOUNT FLAGS LIST | MOUNT EXPRESSION ) MOUNT FLAGS LIST = Comma separated list of MOUNT FLAGS. MOUNT FLAGS = ( 'ro' | 'rw' | 'nosuid' | 'suid' | 'nodev' | 'dev' | 'noexec' | 'exec' | 'sync' | 'async' | 'remount' | 'mand' | 'nomand' | 'dirsync' | 'noatime' | 'atime' | 'nodiratime' | 'diratime' | 'bind' | 'rbind' | 'move' | 'verbose' | 'silent' | 'loud' | 'acl' | 'noacl' | 'unbindable' | 'runbindable' | 'private' | 'rprivate' | 'slave' | 'rslave' | 'shared' | 'rshared' | 'relatime' | 'norelatime' | 'iversion' | 'noiversion' | 'strictatime' | 'nouser' | 'user' ) MOUNT EXPRESSION = ( ALPHANUMERIC | AARE ) ... PIVOT ROOT RULE = [ QUALIFIERS ] pivot_root [ oldroot=OLD PUT FILEGLOB ] [ NEW ROOT FILEGLOB ] SOURCE FILEGLOB = FILEGLOB MOUNTPOINT FILEGLOB = FILEGLOB eg. mount, mount /dev/foo, mount options=ro /dev/foo -> /mnt/, mount options in (ro,atime) /dev/foo -> /mnt/, mount options=ro options=atime, Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com>	2017-09-22 13:00:57 -07:00