[PATCH 6.1.y] jfs: define xtree root and page independently

Aditya Dutt
2025-04-27T15:30:58Z

From: Dave Kleikamp <dave.kleikamp@oracle.com>

[ Upstream commit a779ed754e52d582b8c0e17959df063108bd0656 ]

In order to make array bounds checking sane, provide a separate
definition of the in-inode xtree root and the external xtree page.

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Tested-by: Manas Ghandat <ghandatmanas@gmail.com>
(cherry picked from commit a779ed754e52d582b8c0e17959df063108bd0656)
Closes: https://syzkaller.appspot.com/bug?extid=7cb897779f3c479d0615
Closes: https://syzkaller.appspot.com/bug?extid=6b1d79dad6cc6b3eef41
Closes: https://syzkaller.appspot.com/bug?extid=67f714a53ce18d5b542e
Closes: https://syzkaller.appspot.com/bug?extid=e829cfdd0de521302df4
Reported-by: syzbot+7cb897779f3c479d0615@syzkaller.appspotmail.com
Reported-by: syzbot+6b1d79dad6cc6b3eef41@syzkaller.appspotmail.com
Reported-by: syzbot+67f714a53ce18d5b542e@syzkaller.appspotmail.com
Reported-by: syzbot+e829cfdd0de521302df4@syzkaller.appspotmail.com
Signed-off-by: Aditya Dutt <duttaditya18@gmail.com>
---
I am sending this as per the suggestion by Greg to submit backports for
all the relevant stable trees:
https://lore.kernel.org/stable/2025042210-stylized-nearest-ea59@gregkh/
I will send one more mail for 5.15.
This patch has been applied in >= 6.12
and has been backported to 6.6: 2ff51719ec615e1b373c1811443efe93594c41a9

syzbot checked the patch against 6.1.y and confirmed that the
reproducer did not trigger any issues. check here:
https://lore.kernel.org/all/680e4455.050a0220.3b8549.0082.GAE@google.com/

I also tested the patch manually using the C reproducer:
https://syzkaller.appspot.com/text?tag=ReproC&x=15b291ef680000
(given in the syzkaller dashboard link)

fs/jfs/jfs_dinode.h | 2 +-
fs/jfs/jfs_imap.c | 6 +++---
fs/jfs/jfs_incore.h | 2 +-
fs/jfs/jfs_txnmgr.c | 4 ++--
fs/jfs/jfs_xtree.c | 4 ++--
fs/jfs/jfs_xtree.h | 37 +++++++++++++++++++++++--------------
6 files changed, 32 insertions(+), 23 deletions(-)

diff --git a/fs/jfs/jfs_dinode.h b/fs/jfs/jfs_dinode.h
index 6b231d0d0071..603aae17a693 100644
--- a/fs/jfs/jfs_dinode.h
+++ b/fs/jfs/jfs_dinode.h
@@ -96,7 +96,7 @@ struct dinode {
#define di_gengen u._file._u1._imap._gengen

union {
- xtpage_t _xtroot;
+ xtroot_t _xtroot;
struct {
u8 unused[16]; /* 16: */
dxd_t _dxd; /* 16: */
diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c
index 155f66812934..9adb29e7862c 100644
--- a/fs/jfs/jfs_imap.c
+++ b/fs/jfs/jfs_imap.c
@@ -673,7 +673,7 @@ int diWrite(tid_t tid, struct inode *ip)
* This is the special xtree inside the directory for storing
* the directory table
*/
- xtpage_t *p, *xp;
+ xtroot_t *p, *xp;
xad_t *xad;

jfs_ip->xtlid = 0;
@@ -687,7 +687,7 @@ int diWrite(tid_t tid, struct inode *ip)
* copy xtree root from inode to dinode:
*/
p = &jfs_ip->i_xtroot;
- xp = (xtpage_t *) &dp->di_dirtable;
+ xp = (xtroot_t *) &dp->di_dirtable;
lv = ilinelock->lv;
for (n = 0; n < ilinelock->index; n++, lv++) {
memcpy(&xp->xad[lv->offset], &p->xad[lv->offset],
@@ -716,7 +716,7 @@ int diWrite(tid_t tid, struct inode *ip)
* regular file: 16 byte (XAD slot) granularity
*/
if (type & tlckXTREE) {
- xtpage_t *p, *xp;
+ xtroot_t *p, *xp;
xad_t *xad;

/*
diff --git a/fs/jfs/jfs_incore.h b/fs/jfs/jfs_incore.h
index 721def69e732..dd4264aa9bed 100644
--- a/fs/jfs/jfs_incore.h
+++ b/fs/jfs/jfs_incore.h
@@ -66,7 +66,7 @@ struct jfs_inode_info {
lid_t xtlid; /* lid of xtree lock on directory */
union {
struct {
- xtpage_t _xtroot; /* 288: xtree root */
+ xtroot_t _xtroot; /* 288: xtree root */
struct inomap *_imap; /* 4: inode map header */
} file;
struct {
diff --git a/fs/jfs/jfs_txnmgr.c b/fs/jfs/jfs_txnmgr.c
index ce4b4760fcb1..dccc8b3f1045 100644
--- a/fs/jfs/jfs_txnmgr.c
+++ b/fs/jfs/jfs_txnmgr.c
@@ -783,7 +783,7 @@ struct tlock *txLock(tid_t tid, struct inode *ip, struct metapage * mp,
if (mp->xflag & COMMIT_PAGE)
p = (xtpage_t *) mp->data;
else
- p = &jfs_ip->i_xtroot;
+ p = (xtpage_t *) &jfs_ip->i_xtroot;
xtlck->lwm.offset =
le16_to_cpu(p->header.nextindex);
}
@@ -1676,7 +1676,7 @@ static void xtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,

if (tlck->type & tlckBTROOT) {
lrd->log.redopage.type |= cpu_to_le16(LOG_BTROOT);
- p = &JFS_IP(ip)->i_xtroot;
+ p = (xtpage_t *) &JFS_IP(ip)->i_xtroot;
if (S_ISDIR(ip->i_mode))
lrd->log.redopage.type |=
cpu_to_le16(LOG_DIR_XTREE);
diff --git a/fs/jfs/jfs_xtree.c b/fs/jfs/jfs_xtree.c
index 2d304cee884c..5ee618d17e77 100644
--- a/fs/jfs/jfs_xtree.c
+++ b/fs/jfs/jfs_xtree.c
@@ -1213,7 +1213,7 @@ xtSplitRoot(tid_t tid,
struct xtlock *xtlck;
int rc;

- sp = &JFS_IP(ip)->i_xtroot;
+ sp = (xtpage_t *) &JFS_IP(ip)->i_xtroot;

INCREMENT(xtStat.split);

@@ -2098,7 +2098,7 @@ int xtAppend(tid_t tid, /* transaction id */
*/
void xtInitRoot(tid_t tid, struct inode *ip)
{
- xtpage_t *p;
+ xtroot_t *p;

/*
* acquire a transaction lock on the root
diff --git a/fs/jfs/jfs_xtree.h b/fs/jfs/jfs_xtree.h
index 142caafc73b1..15da4e16d8b2 100644
--- a/fs/jfs/jfs_xtree.h
+++ b/fs/jfs/jfs_xtree.h
@@ -65,24 +65,33 @@ struct xadlist {
#define XTPAGEMAXSLOT 256
#define XTENTRYSTART 2

-/*
- * xtree page:
- */
-typedef union {
- struct xtheader {
- __le64 next; /* 8: */
- __le64 prev; /* 8: */
+struct xtheader {
+ __le64 next; /* 8: */
+ __le64 prev; /* 8: */

- u8 flag; /* 1: */
- u8 rsrvd1; /* 1: */
- __le16 nextindex; /* 2: next index = number of entries */
- __le16 maxentry; /* 2: max number of entries */
- __le16 rsrvd2; /* 2: */
+ u8 flag; /* 1: */
+ u8 rsrvd1; /* 1: */
+ __le16 nextindex; /* 2: next index = number of entries */
+ __le16 maxentry; /* 2: max number of entries */
+ __le16 rsrvd2; /* 2: */

- pxd_t self; /* 8: self */
- } header; /* (32) */
+ pxd_t self; /* 8: self */
+};

+/*
+ * xtree root (in inode):
+ */
+typedef union {
+ struct xtheader header;
xad_t xad[XTROOTMAXSLOT]; /* 16 * maxentry: xad array */
+} xtroot_t;
+
+/*
+ * xtree page:
+ */
+typedef union {
+ struct xtheader header;
+ xad_t xad[XTPAGEMAXSLOT]; /* 16 * maxentry: xad array */
} xtpage_t;

/*
--
2.34.1