FAILED: patch "[PATCH] dm-integrity: validate the superblock on resume" failed to apply to 7.2-stable tree

index 0862f31b8498..802b377613b0 100644
@@ -180,6 +180,7 @@ struct dm_integrity_c {
 	struct dm_bufio_client *bufio;
 	struct workqueue_struct *metadata_wq;
 	struct superblock *sb;
+	struct superblock *sb_copy;
 	unsigned int journal_pages;
 	unsigned int n_bitmap_blocks;
 

@@ -3858,6 +3859,35 @@ static void dm_integrity_postsuspend(struct dm_target *ti)
 	ic->journal_uptodate = true;
 }
 
+/*
+ * The superblock is re-read from the device on every resume, so that we pick
+ * up the flags and the recalculate position. The geometry described by the
+ * superblock must not change though - the in-memory structures (and the
+ * journal in particular) were sized according to the superblock that was
+ * validated in the constructor. Reject a superblock that was modified behind
+ * our back.
+ *
+ * Only the fields that the driver never rewrites may be tested here. In
+ * particular, "version" is recalculated by sb_set_version on every superblock
+ * write and it depends on SB_FLAG_RECALCULATING and SB_FLAG_DIRTY_BITMAP, and
+ * SB_FLAG_DISCARD_KEYED may be set by dm_integrity_resume itself.
+ */
+static bool superblock_changed(struct dm_integrity_c *ic)
+{
+	const __le32 immutable_flags = cpu_to_le32(SB_FLAG_HAVE_JOURNAL_MAC |
+						   SB_FLAG_FIXED_PADDING |
+						   SB_FLAG_FIXED_HMAC |
+						   SB_FLAG_INLINE);
+
+	return memcmp(ic->sb->magic, ic->sb_copy->magic, sizeof(ic->sb->magic)) != 0 ||
+	       ic->sb->log2_interleave_sectors != ic->sb_copy->log2_interleave_sectors ||
+	       ic->sb->integrity_tag_size != ic->sb_copy->integrity_tag_size ||
+	       ic->sb->journal_sections != ic->sb_copy->journal_sections ||
+	       ic->sb->log2_sectors_per_block != ic->sb_copy->log2_sectors_per_block ||
+	       ((ic->sb->flags ^ ic->sb_copy->flags) & immutable_flags) != 0 ||
+	       memcmp(ic->sb->salt, ic->sb_copy->salt, SALT_SIZE) != 0;
+}
+
 static void dm_integrity_resume(struct dm_target *ti)
 {
 	struct dm_integrity_c *ic = ti->private;

@@ -3876,6 +3906,18 @@ static void dm_integrity_resume(struct dm_target *ti)
 	if (r)
 		dm_integrity_io_error(ic, "reading superblock", r);
 
+	if (unlikely(superblock_changed(ic))) {
+		/*
+		 * Restore the superblock that we validated in the constructor,
+		 * so that the rest of the driver doesn't operate on values
+		 * that don't match the in-memory structures.
+		 */
+		memcpy(ic->sb, ic->sb_copy, sizeof(struct superblock));
+		DMERR("The superblock was changed while the device was suspended");
+		dm_integrity_io_error(ic, "superblock check", -EINVAL);
+		goto skip_writes;
+	}
+
 	if (ic->mode == 'R')
 		goto skip_writes;
 

@@ -5427,6 +5469,13 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned int argc, char **argv
 		ic->just_formatted = true;
 	}
 
+	ic->sb_copy = kmemdup(ic->sb, sizeof(struct superblock), GFP_KERNEL);
+	if (!ic->sb_copy) {
+		ti->error = "Cannot allocate superblock copy";
+		r = -ENOMEM;
+		goto bad;
+	}
+
 	if (!ic->meta_dev && ic->mode != 'I') {
 		r = dm_set_target_max_io_len(ti, 1U << ic->sb->log2_interleave_sectors);
 		if (r)

@@ -5525,6 +5574,7 @@ static void dm_integrity_dtr(struct dm_target *ti)
 	kvfree(ic->journal_tree);
 	if (ic->sb)
 		free_pages_exact(ic->sb, SB_SECTORS << SECTOR_SHIFT);
+	kfree(ic->sb_copy);
 
 	if (ic->internal_shash)
 		crypto_free_shash(ic->internal_shash);

index 4bda7b5dba1a6..cded0607b39c0 100644
@@ -3874,6 +3874,10 @@ static void dm_integrity_resume(struct dm_target *ti)
 	r = sync_rw_sb(ic, REQ_OP_READ);
 	if (r)
 		dm_integrity_io_error(ic, "reading superblock", r);
+
+	if (ic->mode == 'R')
+		goto skip_writes;
+
 	if ((ic->sb->flags & flags) != flags) {
 		ic->sb->flags |= flags;
 		r = sync_rw_sb(ic, REQ_OP_WRITE | REQ_FUA);

@@ -3983,6 +3987,7 @@ static void dm_integrity_resume(struct dm_target *ti)
 		}
 	}
 
+skip_writes:
 	ic->reboot_notifier.notifier_call = dm_integrity_reboot;
 	ic->reboot_notifier.next = NULL;
 	ic->reboot_notifier.priority = INT_MAX - 1;	/* be notified after md and before hardware drivers */

index cded0607b39c0..3b36f4b8ec67b 100644
@@ -180,6 +180,7 @@ struct dm_integrity_c {
 	struct dm_bufio_client *bufio;
 	struct workqueue_struct *metadata_wq;
 	struct superblock *sb;
+	struct superblock *sb_copy;
 	unsigned int journal_pages;
 	unsigned int n_bitmap_blocks;
 

@@ -3857,6 +3858,35 @@ static void dm_integrity_postsuspend(struct dm_target *ti)
 	ic->journal_uptodate = true;
 }
 
+/*
+ * The superblock is re-read from the device on every resume, so that we pick
+ * up the flags and the recalculate position. The geometry described by the
+ * superblock must not change though - the in-memory structures (and the
+ * journal in particular) were sized according to the superblock that was
+ * validated in the constructor. Reject a superblock that was modified behind
+ * our back.
+ *
+ * Only the fields that the driver never rewrites may be tested here. In
+ * particular, "version" is recalculated by sb_set_version on every superblock
+ * write and it depends on SB_FLAG_RECALCULATING and SB_FLAG_DIRTY_BITMAP, and
+ * SB_FLAG_DISCARD_KEYED may be set by dm_integrity_resume itself.
+ */
+static bool superblock_changed(struct dm_integrity_c *ic)
+{
+	const __le32 immutable_flags = cpu_to_le32(SB_FLAG_HAVE_JOURNAL_MAC |
+						   SB_FLAG_FIXED_PADDING |
+						   SB_FLAG_FIXED_HMAC |
+						   SB_FLAG_INLINE);
+
+	return memcmp(ic->sb->magic, ic->sb_copy->magic, sizeof(ic->sb->magic)) != 0 ||
+	       ic->sb->log2_interleave_sectors != ic->sb_copy->log2_interleave_sectors ||
+	       ic->sb->integrity_tag_size != ic->sb_copy->integrity_tag_size ||
+	       ic->sb->journal_sections != ic->sb_copy->journal_sections ||
+	       ic->sb->log2_sectors_per_block != ic->sb_copy->log2_sectors_per_block ||
+	       ((ic->sb->flags ^ ic->sb_copy->flags) & immutable_flags) != 0 ||
+	       memcmp(ic->sb->salt, ic->sb_copy->salt, SALT_SIZE) != 0;
+}
+
 static void dm_integrity_resume(struct dm_target *ti)
 {
 	struct dm_integrity_c *ic = ti->private;

@@ -3875,6 +3905,18 @@ static void dm_integrity_resume(struct dm_target *ti)
 	if (r)
 		dm_integrity_io_error(ic, "reading superblock", r);
 
+	if (unlikely(superblock_changed(ic))) {
+		/*
+		 * Restore the superblock that we validated in the constructor,
+		 * so that the rest of the driver doesn't operate on values
+		 * that don't match the in-memory structures.
+		 */
+		memcpy(ic->sb, ic->sb_copy, sizeof(struct superblock));
+		DMERR("The superblock was changed while the device was suspended");
+		dm_integrity_io_error(ic, "superblock check", -EINVAL);
+		goto skip_writes;
+	}
+
 	if (ic->mode == 'R')
 		goto skip_writes;
 

@@ -5421,6 +5463,13 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned int argc, char **argv
 		ic->just_formatted = true;
 	}
 
+	ic->sb_copy = kmemdup(ic->sb, sizeof(struct superblock), GFP_KERNEL);
+	if (!ic->sb_copy) {
+		ti->error = "Cannot allocate superblock copy";
+		r = -ENOMEM;
+		goto bad;
+	}
+
 	if (!ic->meta_dev && ic->mode != 'I') {
 		r = dm_set_target_max_io_len(ti, 1U << ic->sb->log2_interleave_sectors);
 		if (r)

@@ -5519,6 +5568,7 @@ static void dm_integrity_dtr(struct dm_target *ti)
 	kvfree(ic->journal_tree);
 	if (ic->sb)
 		free_pages_exact(ic->sb, SB_SECTORS << SECTOR_SHIFT);
+	kfree(ic->sb_copy);
 
 	if (ic->internal_shash)
 		crypto_free_shash(ic->internal_shash);