bcachefs: Add missing validation for jset_entry_data_usage

Validation was completely missing for replicas entries in the journal
(not the superblock replicas section) - we can't have replicas entries
pointing to invalid devices.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Author: Kent Overstreet

fs/bcachefs/errcode.h

@@ -210,6 +210,7 @@
 	x(BCH_ERR_invalid_sb,		invalid_sb_members)			\
 	x(BCH_ERR_invalid_sb,		invalid_sb_disk_groups)			\
 	x(BCH_ERR_invalid_sb,		invalid_sb_replicas)			\
+	x(BCH_ERR_invalid_sb,		invalid_replicas_entry)			\
 	x(BCH_ERR_invalid_sb,		invalid_sb_journal)			\
 	x(BCH_ERR_invalid_sb,		invalid_sb_journal_seq_blacklist)	\
 	x(BCH_ERR_invalid_sb,		invalid_sb_crypt)			\

fs/bcachefs/journal_io.c

@@ -547,6 +547,7 @@ static int journal_entry_data_usage_validate(struct bch_fs *c,
 	struct jset_entry_data_usage *u =
 		container_of(entry, struct jset_entry_data_usage, entry);
 	unsigned bytes = jset_u64s(le16_to_cpu(entry->u64s)) * sizeof(u64);
+	struct printbuf err = PRINTBUF;
 	int ret = 0;
 
 	if (journal_entry_err_on(bytes < sizeof(*u) ||
@@ -555,10 +556,19 @@ static int journal_entry_data_usage_validate(struct bch_fs *c,
 				 journal_entry_data_usage_bad_size,
 				 "invalid journal entry usage: bad size")) {
 		journal_entry_null_range(entry, vstruct_next(entry));
-		return ret;
+		goto out;
 	}
 
+	if (journal_entry_err_on(bch2_replicas_entry_validate(&u->r, c->disk_sb.sb, &err),
+				 c, version, jset, entry,
+				 journal_entry_data_usage_bad_size,
+				 "invalid journal entry usage: %s", err.buf)) {
+		journal_entry_null_range(entry, vstruct_next(entry));
+		goto out;
+	}
+out:
 fsck_err:
+	printbuf_exit(&err);
 	return ret;
 }
 

fs/bcachefs/replicas.c

@@ -68,6 +68,33 @@ void bch2_replicas_entry_to_text(struct printbuf *out,
 	prt_printf(out, "]");
 }
 
+int bch2_replicas_entry_validate(struct bch_replicas_entry *r,
+				 struct bch_sb *sb,
+				 struct printbuf *err)
+{
+	if (!r->nr_devs) {
+		prt_printf(err, "no devices in entry ");
+		goto bad;
+	}
+
+	if (r->nr_required > 1 &&
+	    r->nr_required >= r->nr_devs) {
+		prt_printf(err, "bad nr_required in entry ");
+		goto bad;
+	}
+
+	for (unsigned i = 0; i < r->nr_devs; i++)
+		if (!bch2_dev_exists(sb, r->devs[i])) {
+			prt_printf(err, "invalid device %u in entry ", r->devs[i]);
+			goto bad;
+		}
+
+	return 0;
+bad:
+	bch2_replicas_entry_to_text(err, r);
+	return -BCH_ERR_invalid_replicas_entry;
+}
+
 void bch2_cpu_replicas_to_text(struct printbuf *out,
 			       struct bch_replicas_cpu *r)
 {
@@ -163,7 +190,8 @@ void bch2_devlist_to_replicas(struct bch_replicas_entry *e,
 }
 
 static struct bch_replicas_cpu
-cpu_replicas_add_entry(struct bch_replicas_cpu *old,
+cpu_replicas_add_entry(struct bch_fs *c,
+		       struct bch_replicas_cpu *old,
 		       struct bch_replicas_entry *new_entry)
 {
 	unsigned i;
@@ -173,6 +201,9 @@ cpu_replicas_add_entry(struct bch_replicas_cpu *old,
 					replicas_entry_bytes(new_entry)),
 	};
 
+	for (i = 0; i < new_entry->nr_devs; i++)
+		BUG_ON(!bch2_dev_exists2(c, new_entry->devs[i]));
+
 	BUG_ON(!new_entry->data_type);
 	verify_replicas_entry(new_entry);
 
@@ -382,15 +413,15 @@ static int bch2_mark_replicas_slowpath(struct bch_fs *c,
 
 	if (c->replicas_gc.entries &&
 	    !__replicas_has_entry(&c->replicas_gc, new_entry)) {
-		new_gc = cpu_replicas_add_entry(&c->replicas_gc, new_entry);
+		new_gc = cpu_replicas_add_entry(c, &c->replicas_gc, new_entry);
 		if (!new_gc.entries) {
 			ret = -BCH_ERR_ENOMEM_cpu_replicas;
 			goto err;
 		}
 	}
 
 	if (!__replicas_has_entry(&c->replicas, new_entry)) {
-		new_r = cpu_replicas_add_entry(&c->replicas, new_entry);
+		new_r = cpu_replicas_add_entry(c, &c->replicas, new_entry);
 		if (!new_r.entries) {
 			ret = -BCH_ERR_ENOMEM_cpu_replicas;
 			goto err;
@@ -598,7 +629,7 @@ int bch2_replicas_set_usage(struct bch_fs *c,
 	if (idx < 0) {
 		struct bch_replicas_cpu n;
 
-		n = cpu_replicas_add_entry(&c->replicas, r);
+		n = cpu_replicas_add_entry(c, &c->replicas, r);
 		if (!n.entries)
 			return -BCH_ERR_ENOMEM_cpu_replicas;
 
@@ -797,7 +828,7 @@ static int bch2_cpu_replicas_validate(struct bch_replicas_cpu *cpu_r,
 				      struct bch_sb *sb,
 				      struct printbuf *err)
 {
-	unsigned i, j;
+	unsigned i;
 
 	sort_cmp_size(cpu_r->entries,
 		      cpu_r->nr,
@@ -808,31 +839,9 @@ static int bch2_cpu_replicas_validate(struct bch_replicas_cpu *cpu_r,
 		struct bch_replicas_entry *e =
 			cpu_replicas_entry(cpu_r, i);
 
-		if (e->data_type >= BCH_DATA_NR) {
-			prt_printf(err, "invalid data type in entry ");
-			bch2_replicas_entry_to_text(err, e);
-			return -BCH_ERR_invalid_sb_replicas;
-		}
-
-		if (!e->nr_devs) {
-			prt_printf(err, "no devices in entry ");
-			bch2_replicas_entry_to_text(err, e);
-			return -BCH_ERR_invalid_sb_replicas;
-		}
-
-		if (e->nr_required > 1 &&
-		    e->nr_required >= e->nr_devs) {
-			prt_printf(err, "bad nr_required in entry ");
-			bch2_replicas_entry_to_text(err, e);
-			return -BCH_ERR_invalid_sb_replicas;
-		}
-
-		for (j = 0; j < e->nr_devs; j++)
-			if (!bch2_dev_exists(sb, e->devs[j])) {
-				prt_printf(err, "invalid device %u in entry ", e->devs[j]);
-				bch2_replicas_entry_to_text(err, e);
-				return -BCH_ERR_invalid_sb_replicas;
-			}
+		int ret = bch2_replicas_entry_validate(e, sb, err);
+		if (ret)
+			return ret;
 
 		if (i + 1 < cpu_r->nr) {
 			struct bch_replicas_entry *n =

fs/bcachefs/replicas.h

@@ -9,6 +9,8 @@
 void bch2_replicas_entry_sort(struct bch_replicas_entry *);
 void bch2_replicas_entry_to_text(struct printbuf *,
 				 struct bch_replicas_entry *);
+int bch2_replicas_entry_validate(struct bch_replicas_entry *,
+				 struct bch_sb *, struct printbuf *);
 void bch2_cpu_replicas_to_text(struct printbuf *, struct bch_replicas_cpu *);
 
 static inline struct bch_replicas_entry *