1 files changed, 139 insertions, 2 deletions

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index cf659c8feb29..36e4ddfe2d15 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -22,6 +22,7 @@
 #include <linux/scatterlist.h>
 #include <linux/string.h>
 #include <linux/jump_label.h>
+#include <linux/security.h>
 
 #define DM_MSG_PREFIX			"verity"
 
@@ -272,8 +273,10 @@ out:
 	if (v->mode == DM_VERITY_MODE_LOGGING)
 		return 0;
 
-	if (v->mode == DM_VERITY_MODE_RESTART)
-		kernel_restart("dm-verity device corrupted");
+	if (v->mode == DM_VERITY_MODE_RESTART) {
+		pr_emerg("dm-verity device corrupted\n");
+		emergency_restart();
+	}
 
 	if (v->mode == DM_VERITY_MODE_PANIC)
 		panic("dm-verity device corrupted");
@@ -596,6 +599,23 @@ static void verity_finish_io(struct dm_verity_io *io, blk_status_t status)
 	if (!static_branch_unlikely(&use_bh_wq_enabled) || !io->in_bh)
 		verity_fec_finish_io(io);
 
+	if (unlikely(status != BLK_STS_OK) &&
+	    unlikely(!(bio->bi_opf & REQ_RAHEAD)) &&
+	    !verity_is_system_shutting_down()) {
+		if (v->mode == DM_VERITY_MODE_RESTART ||
+		    v->mode == DM_VERITY_MODE_PANIC)
+			DMERR_LIMIT("%s has error: %s", v->data_dev->name,
+					blk_status_to_str(status));
+
+		if (v->mode == DM_VERITY_MODE_RESTART) {
+			pr_emerg("dm-verity device corrupted\n");
+			emergency_restart();
+		}
+
+		if (v->mode == DM_VERITY_MODE_PANIC)
+			panic("dm-verity device corrupted");
+	}
+
 	bio_endio(bio);
 }
 
@@ -930,6 +950,41 @@ static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits)
 	limits->dma_alignment = limits->logical_block_size - 1;
 }
 
+#ifdef CONFIG_SECURITY
+
+static int verity_init_sig(struct dm_verity *v, const void *sig,
+			   size_t sig_size)
+{
+	v->sig_size = sig_size;
+
+	if (sig) {
+		v->root_digest_sig = kmemdup(sig, v->sig_size, GFP_KERNEL);
+		if (!v->root_digest_sig)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void verity_free_sig(struct dm_verity *v)
+{
+	kfree(v->root_digest_sig);
+}
+
+#else
+
+static inline int verity_init_sig(struct dm_verity *v, const void *sig,
+				  size_t sig_size)
+{
+	return 0;
+}
+
+static inline void verity_free_sig(struct dm_verity *v)
+{
+}
+
+#endif /* CONFIG_SECURITY */
+
 static void verity_dtr(struct dm_target *ti)
 {
 	struct dm_verity *v = ti->private;
@@ -949,6 +1004,7 @@ static void verity_dtr(struct dm_target *ti)
 	kfree(v->initial_hashstate);
 	kfree(v->root_digest);
 	kfree(v->zero_digest);
+	verity_free_sig(v);
 
 	if (v->ahash_tfm) {
 		static_branch_dec(&ahash_enabled);
@@ -1418,6 +1474,13 @@ static int verity_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		ti->error = "Root hash verification failed";
 		goto bad;
 	}
+
+	r = verity_init_sig(v, verify_args.sig, verify_args.sig_size);
+	if (r < 0) {
+		ti->error = "Cannot allocate root digest signature";
+		goto bad;
+	}
+
 	v->hash_per_block_bits =
 		__fls((1 << v->hash_dev_block_bits) / v->digest_size);
 
@@ -1559,8 +1622,79 @@ int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest, unsigned i
 	return 0;
 }
 
+#ifdef CONFIG_SECURITY
+
+#ifdef CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG
+
+static int verity_security_set_signature(struct block_device *bdev,
+					 struct dm_verity *v)
+{
+	/*
+	 * if the dm-verity target is unsigned, v->root_digest_sig will
+	 * be NULL, and the hook call is still required to let LSMs mark
+	 * the device as unsigned. This information is crucial for LSMs to
+	 * block operations such as execution on unsigned files
+	 */
+	return security_bdev_setintegrity(bdev,
+					  LSM_INT_DMVERITY_SIG_VALID,
+					  v->root_digest_sig,
+					  v->sig_size);
+}
+
+#else
+
+static inline int verity_security_set_signature(struct block_device *bdev,
+						struct dm_verity *v)
+{
+	return 0;
+}
+
+#endif /* CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG */
+
+/*
+ * Expose verity target's root hash and signature data to LSMs before resume.
+ *
+ * Returns 0 on success, or -ENOMEM if the system is out of memory.
+ */
+static int verity_preresume(struct dm_target *ti)
+{
+	struct block_device *bdev;
+	struct dm_verity_digest root_digest;
+	struct dm_verity *v;
+	int r;
+
+	v = ti->private;
+	bdev = dm_disk(dm_table_get_md(ti->table))->part0;
+	root_digest.digest = v->root_digest;
+	root_digest.digest_len = v->digest_size;
+	if (static_branch_unlikely(&ahash_enabled) && !v->shash_tfm)
+		root_digest.alg = crypto_ahash_alg_name(v->ahash_tfm);
+	else
+		root_digest.alg = crypto_shash_alg_name(v->shash_tfm);
+
+	r = security_bdev_setintegrity(bdev, LSM_INT_DMVERITY_ROOTHASH, &root_digest,
+				       sizeof(root_digest));
+	if (r)
+		return r;
+
+	r =  verity_security_set_signature(bdev, v);
+	if (r)
+		goto bad;
+
+	return 0;
+
+bad:
+
+	security_bdev_setintegrity(bdev, LSM_INT_DMVERITY_ROOTHASH, NULL, 0);
+
+	return r;
+}
+
+#endif /* CONFIG_SECURITY */
+
 static struct target_type verity_target = {
 	.name		= "verity",
+/* Note: the LSMs depend on the singleton and immutable features */
 	.features	= DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE,
 	.version	= {1, 10, 0},
 	.module		= THIS_MODULE,
@@ -1571,6 +1705,9 @@ static struct target_type verity_target = {
 	.prepare_ioctl	= verity_prepare_ioctl,
 	.iterate_devices = verity_iterate_devices,
 	.io_hints	= verity_io_hints,
+#ifdef CONFIG_SECURITY
+	.preresume	= verity_preresume,
+#endif /* CONFIG_SECURITY */
 };
 module_dm(verity);