1 files changed, 27 insertions, 7 deletions

diff --git a/fs/ubifs/tnc_commit.c b/fs/ubifs/tnc_commit.c
index a384a0f9ff32..234be1c4dc87 100644
--- a/fs/ubifs/tnc_commit.c
+++ b/fs/ubifs/tnc_commit.c
@@ -212,7 +212,7 @@ static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key,
 /**
  * layout_leb_in_gaps - layout index nodes using in-the-gaps method.
  * @c: UBIFS file-system description object
- * @p: return LEB number here
+ * @p: return LEB number in @c->gap_lebs[p]
  *
  * This function lays out new index nodes for dirty znodes using in-the-gaps
  * method of TNC commit.
@@ -221,7 +221,7 @@ static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key,
  * This function returns the number of index nodes written into the gaps, or a
  * negative error code on failure.
  */
-static int layout_leb_in_gaps(struct ubifs_info *c, int *p)
+static int layout_leb_in_gaps(struct ubifs_info *c, int p)
 {
 	struct ubifs_scan_leb *sleb;
 	struct ubifs_scan_node *snod;
@@ -236,7 +236,7 @@ static int layout_leb_in_gaps(struct ubifs_info *c, int *p)
 		 * filled, however we do not check there at present.
 		 */
 		return lnum; /* Error code */
-	*p = lnum;
+	c->gap_lebs[p] = lnum;
 	dbg_gc("LEB %d", lnum);
 	/*
 	 * Scan the index LEB.  We use the generic scan for this even though
@@ -355,7 +355,7 @@ static int get_leb_cnt(struct ubifs_info *c, int cnt)
  */
 static int layout_in_gaps(struct ubifs_info *c, int cnt)
 {
-	int err, leb_needed_cnt, written, *p;
+	int err, leb_needed_cnt, written, p = 0, old_idx_lebs, *gap_lebs;
 
 	dbg_gc("%d znodes to write", cnt);
 
@@ -364,9 +364,9 @@ static int layout_in_gaps(struct ubifs_info *c, int cnt)
 	if (!c->gap_lebs)
 		return -ENOMEM;
 
-	p = c->gap_lebs;
+	old_idx_lebs = c->lst.idx_lebs;
 	do {
-		ubifs_assert(c, p < c->gap_lebs + c->lst.idx_lebs);
+		ubifs_assert(c, p < c->lst.idx_lebs);
 		written = layout_leb_in_gaps(c, p);
 		if (written < 0) {
 			err = written;
@@ -392,9 +392,29 @@ static int layout_in_gaps(struct ubifs_info *c, int cnt)
 		leb_needed_cnt = get_leb_cnt(c, cnt);
 		dbg_gc("%d znodes remaining, need %d LEBs, have %d", cnt,
 		       leb_needed_cnt, c->ileb_cnt);
+		/*
+		 * Dynamically change the size of @c->gap_lebs to prevent
+		 * oob, because @c->lst.idx_lebs could be increased by
+		 * function @get_idx_gc_leb (called by layout_leb_in_gaps->
+		 * ubifs_find_dirty_idx_leb) during loop. Only enlarge
+		 * @c->gap_lebs when needed.
+		 *
+		 */
+		if (leb_needed_cnt > c->ileb_cnt && p >= old_idx_lebs &&
+		    old_idx_lebs < c->lst.idx_lebs) {
+			old_idx_lebs = c->lst.idx_lebs;
+			gap_lebs = krealloc(c->gap_lebs, sizeof(int) *
+					       (old_idx_lebs + 1), GFP_NOFS);
+			if (!gap_lebs) {
+				kfree(c->gap_lebs);
+				c->gap_lebs = NULL;
+				return -ENOMEM;
+			}
+			c->gap_lebs = gap_lebs;
+		}
 	} while (leb_needed_cnt > c->ileb_cnt);
 
-	*p = -1;
+	c->gap_lebs[p] = -1;
 	return 0;
 }