[PATCH] jfs : fs array-index-out-of-bounds in txCommit

[Manas Ghandat]

Currently there is no check for out of bound access for xad in the
struct xtpage_t. Added the required check at various places for the same

Signed-off-by: Manas Ghandat <ghandatmanas@xxxxxxxxx>
Reported-by: syzbot+0558d19c373e44da3c18@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=0558d19c373e44da3c18
Fixes: df0cc57e057f
---
 fs/jfs/jfs_txnmgr.c | 4 ++++
 fs/jfs/jfs_xtree.c  | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/fs/jfs/jfs_txnmgr.c b/fs/jfs/jfs_txnmgr.c
index ce4b4760fcb1..6c6640942bed 100644
--- a/fs/jfs/jfs_txnmgr.c
+++ b/fs/jfs/jfs_txnmgr.c
@@ -1722,6 +1722,10 @@ static void xtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
 			jfs_err("xtLog: lwm > next");
 			goto out;
 		}
+		if (lwm >= XTROOTMAXSLOT) {
+			jfs_err("xtLog: lwm out of range");
+			goto out;
+		}
 		tlck->flag |= tlckUPDATEMAP;
 		xadlock->flag = mlckALLOCXADLIST;
 		xadlock->count = next - lwm;
diff --git a/fs/jfs/jfs_xtree.c b/fs/jfs/jfs_xtree.c
index 2d304cee884c..57569c52663e 100644
--- a/fs/jfs/jfs_xtree.c
+++ b/fs/jfs/jfs_xtree.c
@@ -357,6 +357,9 @@ static int xtSearch(struct inode *ip, s64 xoff,	s64 *nextp,
 		for (base = XTENTRYSTART; lim; lim >>= 1) {
 			index = base + (lim >> 1);
 
+			if (index >= XTROOTMAXSLOT)
+				goto out;
+
 			XT_CMP(cmp, xoff, &p->xad[index], t64);
 			if (cmp == 0) {
 				/*
@@ -618,6 +621,9 @@ int xtInsert(tid_t tid,		/* transaction id */
 		memmove(&p->xad[index + 1], &p->xad[index],
 			(nextindex - index) * sizeof(xad_t));
 
+	if (index >= XTROOTMAXSLOT)
+		goto out;
+
 	/* insert the new entry: mark the entry NEW */
 	xad = &p->xad[index];
 	XT_PUTENTRY(xad, xflag, xoff, xlen, xaddr);
-- 
2.37.2