| Message ID | 20230818152910.176044-1-cgzones@googlemail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Paul Moore |
| Headers | show |
| Series | selinux: reject invalid ebitmaps | expand |
On Fri, Aug 18, 2023 at 11:29 AM Christian Göttsche <cgzones@googlemail.com> wrote: > > Reject ebitmaps with a node containing an empty map or with an incorrect > highbit. Both checks are already performed by userspace, the former > since 2008 (patch 13cd4c896068 ("initial import from svn trunk revision > 2950")), the latter since v2.7 in 2017 (patch 75b14a5de10a ("libsepol: > ebitmap: reject loading bitmaps with incorrect high bit")). > > Signed-off-by: Christian Göttsche <cgzones@googlemail.com> Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
On Aug 18, 2023 Stephen Smalley <stephen.smalley.work@gmail.com> wrote: > > Reject ebitmaps with a node containing an empty map or with an incorrect > highbit. Both checks are already performed by userspace, the former > since 2008 (patch 13cd4c896068 ("initial import from svn trunk revision > 2950")), the latter since v2.7 in 2017 (patch 75b14a5de10a ("libsepol: > ebitmap: reject loading bitmaps with incorrect high bit")). > > Signed-off-by: Christian Göttsche <cgzones@googlemail.com> > Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com> > --- > security/selinux/ss/ebitmap.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/security/selinux/ss/ebitmap.c b/security/selinux/ss/ebitmap.c > index 77875ad355f7..ac9da819531d 100644 > --- a/security/selinux/ss/ebitmap.c > +++ b/security/selinux/ss/ebitmap.c ... > @@ -457,6 +461,13 @@ int ebitmap_read(struct ebitmap *e, void *fp) > map = EBITMAP_SHIFT_UNIT_SIZE(map); > } > } > + > + if (n && n->startbit + EBITMAP_SIZE != e->highbit) { > + pr_err("SELinux: ebitmap: high bit %d has not the expected value %ld\n", That reads a little awkward in English, how about "high bit %d is not equal to the expected value %ld\n"? > + e->highbit, n->startbit + EBITMAP_SIZE); > + goto bad; > + } > + > ok: > rc = 0; > out: > -- > 2.40.1 -- paul-moore.com
diff --git a/security/selinux/ss/ebitmap.c b/security/selinux/ss/ebitmap.c index 77875ad355f7..ac9da819531d 100644 --- a/security/selinux/ss/ebitmap.c +++ b/security/selinux/ss/ebitmap.c @@ -450,6 +450,10 @@ int ebitmap_read(struct ebitmap *e, void *fp) goto bad; } map = le64_to_cpu(mapbits); + if (!map) { + pr_err("SELinux: ebitmap: empty map\n"); + goto bad; + } index = (startbit - n->startbit) / EBITMAP_UNIT_SIZE; while (map) { @@ -457,6 +461,13 @@ int ebitmap_read(struct ebitmap *e, void *fp) map = EBITMAP_SHIFT_UNIT_SIZE(map); } } + + if (n && n->startbit + EBITMAP_SIZE != e->highbit) { + pr_err("SELinux: ebitmap: high bit %d has not the expected value %ld\n", + e->highbit, n->startbit + EBITMAP_SIZE); + goto bad; + } + ok: rc = 0; out:
Reject ebitmaps with a node containing an empty map or with an incorrect highbit. Both checks are already performed by userspace, the former since 2008 (patch 13cd4c896068 ("initial import from svn trunk revision 2950")), the latter since v2.7 in 2017 (patch 75b14a5de10a ("libsepol: ebitmap: reject loading bitmaps with incorrect high bit")). Signed-off-by: Christian Göttsche <cgzones@googlemail.com> --- security/selinux/ss/ebitmap.c | 11 +++++++++++ 1 file changed, 11 insertions(+)