Messages in this thread |  | | Subject | Re: [PATCH] apparmor: initialized returned struct aa_perms | From | John Johansen <> | Date | Mon, 20 Nov 2017 07:47:00 -0800 |
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On 11/20/2017 06:00 AM, Arnd Bergmann wrote: > On Mon, Sep 25, 2017 at 4:29 PM, John Johansen > <john.johansen@canonical.com> wrote: >> On 09/15/2017 03:55 PM, Arnd Bergmann wrote: >>> 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 >>> intialized 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 unintialized 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> >> >> I've pulled this into apparmor-next > > It apparently never made it into mainline. What happened? > > Arnd > Its in apparmor-next and is going with today's pull request
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