* [PATCH 1/2] ipe: fix use-after-free when auditing a newly loaded policy
2026-09-23 3:13 [PATCH 0/2] ipe: fix two use-after-frees Fan Wu
@ 2026-09-23 3:13 ` Fan Wu
2026-09-23 3:13 ` [PATCH 2/2] ipe: protect the dm-verity root hash with RCU Fan Wu
2026-09-23 3:37 ` [PATCH 0/2] ipe: fix two use-after-frees Fan Wu
2 siblings, 0 replies; 4+ messages in thread
From: Fan Wu @ 2026-09-23 3:13 UTC (permalink / raw)
To: linux-security-module; +Cc: paul, linux-kernel
new_policy() audits the policy after ipe_new_policyfs_node() publishes it
and drops the new directory's inode lock. A concurrent delete can free
the policy while ipe_audit_policy_load() is still using it.
Audit the successful load under that lock.
Fixes: f44554b5067b ("audit,ipe: add IPE auditing support")
Cc: stable@vger.kernel.org
Assisted-by: claude-opus-5.5
Signed-off-by: Fan Wu <wufan@kernel.org>
---
security/ipe/fs.c | 8 +++-----
security/ipe/policy_fs.c | 3 +++
2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/security/ipe/fs.c b/security/ipe/fs.c
index 076c111c85c8..847a76afb93d 100644
--- a/security/ipe/fs.c
+++ b/security/ipe/fs.c
@@ -159,18 +159,16 @@ static ssize_t new_policy(struct file *f, const char __user *data,
}
rc = ipe_new_policyfs_node(p);
- if (rc)
- goto out;
out:
kfree(copy);
if (rc < 0) {
ipe_free_policy(p);
ipe_audit_policy_load(ERR_PTR(rc));
- } else {
- ipe_audit_policy_load(p);
+ return rc;
}
- return (rc < 0) ? rc : len;
+
+ return len;
}
static const struct file_operations np_fops = {
diff --git a/security/ipe/policy_fs.c b/security/ipe/policy_fs.c
index 9d92d8a14b13..a7aeb57483c6 100644
--- a/security/ipe/policy_fs.c
+++ b/security/ipe/policy_fs.c
@@ -481,6 +481,9 @@ int ipe_new_policyfs_node(struct ipe_policy *p)
inode_lock(root);
p->policyfs = policyfs;
root->i_private = p;
+ /* Only audit signed policies from userspace */
+ if (p->pkcs7)
+ ipe_audit_policy_load(p);
inode_unlock(root);
return 0;
--
2.55.0
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH 2/2] ipe: protect the dm-verity root hash with RCU
2026-09-23 3:13 [PATCH 0/2] ipe: fix two use-after-frees Fan Wu
2026-09-23 3:13 ` [PATCH 1/2] ipe: fix use-after-free when auditing a newly loaded policy Fan Wu
@ 2026-09-23 3:13 ` Fan Wu
2026-09-23 3:37 ` [PATCH 0/2] ipe: fix two use-after-frees Fan Wu
2 siblings, 0 replies; 4+ messages in thread
From: Fan Wu @ 2026-09-23 3:13 UTC (permalink / raw)
To: linux-security-module; +Cc: paul, linux-kernel
ipe_bdev_setintegrity() frees the old root hash when dm-verity publishes
a new one on ->preresume, while policy evaluation can still be
dereferencing it.
Protect the root hash with RCU. The evaluation path already runs under
rcu_read_lock().
Fixes: e155858dd995 ("ipe: add support for dm-verity as a trust provider")
Cc: stable@vger.kernel.org
Assisted-by: claude-opus-5.5
Signed-off-by: Fan Wu <wufan@kernel.org>
---
security/ipe/eval.c | 12 ++++++++----
security/ipe/eval.h | 2 +-
security/ipe/hooks.c | 22 +++++++++++++++++-----
3 files changed, 26 insertions(+), 10 deletions(-)
diff --git a/security/ipe/eval.c b/security/ipe/eval.c
index 21439c5be336..4a7be96c84f0 100644
--- a/security/ipe/eval.c
+++ b/security/ipe/eval.c
@@ -134,10 +134,14 @@ static bool evaluate_boot_verified(const struct ipe_eval_ctx *const ctx)
static bool evaluate_dmv_roothash(const struct ipe_eval_ctx *const ctx,
struct ipe_prop *p)
{
- return !!ctx->ipe_bdev &&
- !!ctx->ipe_bdev->root_hash &&
- ipe_digest_eval(p->value,
- ctx->ipe_bdev->root_hash);
+ const struct digest_info *root_hash;
+
+ if (!ctx->ipe_bdev)
+ return false;
+
+ root_hash = rcu_dereference(ctx->ipe_bdev->root_hash);
+
+ return root_hash && ipe_digest_eval(p->value, root_hash);
}
#else
static bool evaluate_dmv_roothash(const struct ipe_eval_ctx *const ctx,
diff --git a/security/ipe/eval.h b/security/ipe/eval.h
index fef65a36468c..b26d1147d070 100644
--- a/security/ipe/eval.h
+++ b/security/ipe/eval.h
@@ -27,7 +27,7 @@ struct ipe_bdev {
#ifdef CONFIG_IPE_PROP_DM_VERITY_SIGNATURE
bool dm_verity_signed;
#endif /* CONFIG_IPE_PROP_DM_VERITY_SIGNATURE */
- struct digest_info *root_hash;
+ struct digest_info __rcu *root_hash;
};
#endif /* CONFIG_IPE_PROP_DM_VERITY */
diff --git a/security/ipe/hooks.c b/security/ipe/hooks.c
index 0ae54a880405..d878b52ceec8 100644
--- a/security/ipe/hooks.c
+++ b/security/ipe/hooks.c
@@ -9,6 +9,7 @@
#include <linux/binfmts.h>
#include <linux/mman.h>
#include <linux/blk_types.h>
+#include <linux/rcupdate.h>
#include "ipe.h"
#include "hooks.h"
@@ -232,7 +233,20 @@ void ipe_bdev_free_security(struct block_device *bdev)
{
struct ipe_bdev *blob = ipe_bdev(bdev);
- ipe_digest_free(blob->root_hash);
+ ipe_digest_free(rcu_access_pointer(blob->root_hash));
+}
+
+static void ipe_set_dmverity_roothash(struct ipe_bdev *blob,
+ struct digest_info *info)
+{
+ struct digest_info *old;
+
+ /* Protected by device-mapper's md->suspend_lock */
+ old = rcu_replace_pointer(blob->root_hash, info, true);
+ if (old) {
+ synchronize_rcu();
+ ipe_digest_free(old);
+ }
}
#ifdef CONFIG_IPE_PROP_DM_VERITY_SIGNATURE
@@ -280,8 +294,7 @@ int ipe_bdev_setintegrity(struct block_device *bdev, enum lsm_integrity_type typ
return -EINVAL;
if (!value) {
- ipe_digest_free(blob->root_hash);
- blob->root_hash = NULL;
+ ipe_set_dmverity_roothash(blob, NULL);
return 0;
}
@@ -301,8 +314,7 @@ int ipe_bdev_setintegrity(struct block_device *bdev, enum lsm_integrity_type typ
info->digest_len = digest->digest_len;
- ipe_digest_free(blob->root_hash);
- blob->root_hash = info;
+ ipe_set_dmverity_roothash(blob, info);
return 0;
err:
--
2.55.0
^ permalink raw reply [flat|nested] 4+ messages in thread