libsepol/0004-libsepol-Check-kernel-to-CIL-and-Conf-functions-for-.patch
Petr Lautrbach c59879b8aa libsepol-3.2-3
Rebase on upstream commit 32611aea6543

See
    $ cd SELinuxProject/selinux
    $ git log --pretty=oneline libsepol-3.2..32611aea6543 -- libsepol
2021-07-28 12:45:25 +02:00

92 lines
3.2 KiB
Diff

From 43c5ed469c2f3bc1beed9110b72bcc29c367ecfb Mon Sep 17 00:00:00 2001
From: James Carter <jwcart2@gmail.com>
Date: Mon, 15 Mar 2021 11:09:38 -0400
Subject: [PATCH] libsepol: Check kernel to CIL and Conf functions for
supported versions
For policy versions between 20 and 23, attributes exist in the
policy, but only in the type_attr_map. This means that there are
gaps in both the type_val_to_struct and p_type_val_to_name arrays
and policy rules can refer to those gaps which can lead to NULL
dereferences when using sepol_kernel_policydb_to_conf() and
sepol_kernel_policydb_to_cil().
This can be seen with the following policy:
class CLASS1
sid SID1
class CLASS1 { PERM1 }
attribute TYPE_ATTR1;
type TYPE1;
typeattribute TYPE1 TYPE_ATTR1;
allow TYPE_ATTR1 self : CLASS1 PERM1;
role ROLE1;
role ROLE1 types TYPE1;
user USER1 roles ROLE1;
sid SID1 USER1:ROLE1:TYPE1
Compile the policy:
checkpolicy -c 23 -o policy.bin policy.conf
Converting back to a policy.conf causes a segfault:
checkpolicy -F -b -o policy.bin.conf policy.bin
Have both sepol_kernel_policydb_to_conf() and
sepol_kernel_policydb_to_cil() exit with an error if the kernel
policy version is between 20 and 23.
Acked-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Signed-off-by: James Carter <jwcart2@gmail.com>
---
libsepol/src/kernel_to_cil.c | 12 ++++++++++++
libsepol/src/kernel_to_conf.c | 12 ++++++++++++
2 files changed, 24 insertions(+)
diff --git a/libsepol/src/kernel_to_cil.c b/libsepol/src/kernel_to_cil.c
index a146ac514018..edfebeafe283 100644
--- a/libsepol/src/kernel_to_cil.c
+++ b/libsepol/src/kernel_to_cil.c
@@ -3164,6 +3164,18 @@ int sepol_kernel_policydb_to_cil(FILE *out, struct policydb *pdb)
goto exit;
}
+ if (pdb->policyvers >= POLICYDB_VERSION_AVTAB && pdb->policyvers <= POLICYDB_VERSION_PERMISSIVE) {
+ /*
+ * For policy versions between 20 and 23, attributes exist in the policy,
+ * but only in the type_attr_map. This means that there are gaps in both
+ * the type_val_to_struct and p_type_val_to_name arrays and policy rules
+ * can refer to those gaps.
+ */
+ sepol_log_err("Writing policy versions between 20 and 23 as CIL is not supported");
+ rc = -1;
+ goto exit;
+ }
+
rc = constraint_rules_to_strs(pdb, mls_constraints, non_mls_constraints);
if (rc != 0) {
goto exit;
diff --git a/libsepol/src/kernel_to_conf.c b/libsepol/src/kernel_to_conf.c
index a22f196df9e9..ea58a026501f 100644
--- a/libsepol/src/kernel_to_conf.c
+++ b/libsepol/src/kernel_to_conf.c
@@ -3041,6 +3041,18 @@ int sepol_kernel_policydb_to_conf(FILE *out, struct policydb *pdb)
goto exit;
}
+ if (pdb->policyvers >= POLICYDB_VERSION_AVTAB && pdb->policyvers <= POLICYDB_VERSION_PERMISSIVE) {
+ /*
+ * For policy versions between 20 and 23, attributes exist in the policy,
+ * but only in the type_attr_map. This means that there are gaps in both
+ * the type_val_to_struct and p_type_val_to_name arrays and policy rules
+ * can refer to those gaps.
+ */
+ sepol_log_err("Writing policy versions between 20 and 23 as a policy.conf is not supported");
+ rc = -1;
+ goto exit;
+ }
+
rc = constraint_rules_to_strs(pdb, mls_constraints, non_mls_constraints);
if (rc != 0) {
goto exit;
--
2.32.0