From 102aefdda4d8275ce7d7100bc16c88c74272b260 Mon Sep 17 00:00:00 2001 From: Anand Avati Date: Tue, 16 Apr 2013 18:56:19 -0400 Subject: selinux: consider filesystem subtype in policies Not considering sub filesystem has the following limitation. Support for SELinux in FUSE is dependent on the particular userspace filesystem, which is identified by the subtype. For e.g, GlusterFS, a FUSE based filesystem supports SELinux (by mounting and processing FUSE requests in different threads, avoiding the mount time deadlock), whereas other FUSE based filesystems (identified by a different subtype) have the mount time deadlock. By considering the subtype of the filesytem in the SELinux policies, allows us to specify a filesystem subtype, in the following way: fs_use_xattr fuse.glusterfs gen_context(system_u:object_r:fs_t,s0); This way not all FUSE filesystems are put in the same bucket and subjected to the limitations of the other subtypes. Signed-off-by: Anand Avati Signed-off-by: Eric Paris --- security/selinux/ss/services.c | 42 ++++++++++++++++++++++++++++++++++++++---- 1 file changed, 38 insertions(+), 4 deletions(-) (limited to 'security/selinux/ss/services.c') diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index d106733ad987..ee470a0b5c27 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -2334,16 +2334,50 @@ int security_fs_use(struct super_block *sb) struct ocontext *c; struct superblock_security_struct *sbsec = sb->s_security; const char *fstype = sb->s_type->name; + const char *subtype = (sb->s_subtype && sb->s_subtype[0]) ? sb->s_subtype : NULL; + struct ocontext *base = NULL; read_lock(&policy_rwlock); - c = policydb.ocontexts[OCON_FSUSE]; - while (c) { - if (strcmp(fstype, c->u.name) == 0) + for (c = policydb.ocontexts[OCON_FSUSE]; c; c = c->next) { + char *sub; + int baselen; + + baselen = strlen(fstype); + + /* if base does not match, this is not the one */ + if (strncmp(fstype, c->u.name, baselen)) + continue; + + /* if there is no subtype, this is the one! */ + if (!subtype) + break; + + /* skip past the base in this entry */ + sub = c->u.name + baselen; + + /* entry is only a base. save it. keep looking for subtype */ + if (sub[0] == '\0') { + base = c; + continue; + } + + /* entry is not followed by a subtype, so it is not a match */ + if (sub[0] != '.') + continue; + + /* whew, we found a subtype of this fstype */ + sub++; /* move past '.' */ + + /* exact match of fstype AND subtype */ + if (!strcmp(subtype, sub)) break; - c = c->next; } + /* in case we had found an fstype match but no subtype match */ + if (!c) + c = base; + if (c) { sbsec->behavior = c->v.behavior; if (!c->sid[0]) { -- cgit v1.2.3