From 9b46fba7528f58ca09eac67ec7d474ff1e9af066 Mon Sep 17 00:00:00 2001 From: Bryam Vargas Date: Mon, 27 Jul 2026 20:30:58 -0500 Subject: [PATCH] selinux: reject a permission value exceeding the class permission count commit d14b5d0e97fccd27974fedc03b903408872907fd upstream. 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: stable@vger.kernel.org Fixes: 55fcf09b3fe4 ("selinux: add support for querying object classes and permissions from the running policy") Signed-off-by: Bryam Vargas Acked-by: Stephen Smalley [PM: tweak comment for line length] Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman --- 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 69c19ef4b881..fdb8a62da04a 100644 --- a/security/selinux/ss/policydb.c +++ b/security/selinux/ss/policydb.c @@ -1168,6 +1168,9 @@ static int perm_read(struct policydb *p, struct symtab *s, struct policy_file *f rc = symtab_insert(s, key, perdatum); if (rc) goto bad; + /* indexes an nprim-sized array in security_get_permissions() */ + if (perdatum->value > s->nprim) + goto bad; return 0; bad: