[PATCH 6.18.y 5/7] selinux: reject a permission value exceeding the class permission count
Wentao Guan <[email protected]>
| Newsgroups | org.kernel.vger.stable |
|---|---|
| Message-ID | <[email protected]> |
From: Bryam Vargas <[email protected]> perm_read() bounds a permission value by SEL_VEC_MAX but never by the nprim of the owning class or common, which is taken verbatim from the policy image. security_get_permissions() then writes perms[value - 1] into an nprim-sized kcalloc() array, so a class declaring fewer permissions than its largest permission value drives an out-of-bounds heap write. The top-level symbol tables are validated this way; the nested per-class permission table is not. Reject a permission whose value exceeds nprim, which is already set when perm_read() runs. Well-formed policies are unaffected. Cc: [email protected] Fixes: 55fcf09b3fe4 ("selinux: add support for querying object classes and permissions from the running policy") Signed-off-by: Bryam Vargas <[email protected]> Acked-by: Stephen Smalley <[email protected]> [PM: tweak comment for line length] Signed-off-by: Paul Moore <[email protected]> (cherry picked from commit d14b5d0e97fccd27974fedc03b903408872907fd) Signed-off-by: Wentao Guan <[email protected]> --- security/selinux/ss/policydb.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c index 8dc77e347a77f..a3d52beb65487 100644 --- a/security/selinux/ss/policydb.c +++ b/security/selinux/ss/policydb.c @@ -1160,6 +1160,9 @@ static int perm_read(struct policydb *p, struct symtab *s, struct policy_file *f rc = -EINVAL; if (perdatum->value < 1 || perdatum->value > SEL_VEC_MAX) goto bad; + /* indexes an nprim-sized array in security_get_permissions() */ + if (perdatum->value > s->nprim) + goto bad; rc = str_read(&key, GFP_KERNEL, fp, len); if (rc) -- 2.30.2