Skip to content

Commit c83abc7

Browse files
zhouyun1306kleikamp
zhouyun1306
authored and
kleikamp
committed
jfs: add dtroot integrity check to prevent index out-of-bounds
Add check_dtroot() to validate dtroot_t integrity, focusing on preventing index/pointer overflows from on-disk corruption. Key checks: - freecnt bounded by [0, DTROOTMAXSLOT-1] (slot[0] reserved for header). - freelist validity: -1 when freecnt=0; 1~DTROOTMAXSLOT-1 when non-zero, with linked list checks (no duplicates, proper termination via next=-1). - stbl bounds: nextindex within stbl array size; entries within 0~8, no duplicates (excluding idx=0). Invoked in copy_from_dinode() when loading directory inodes, catching corruption early before directory operations trigger out-of-bounds access. This fixes the following UBSAN warning. [ 101.832754][ T5960] ------------[ cut here ]------------ [ 101.832762][ T5960] UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:3713:8 [ 101.832792][ T5960] index -1 is out of range for type 'struct dtslot[128]' [ 101.832807][ T5960] CPU: 2 UID: 0 PID: 5960 Comm: 5f7f0caf9979e9d Tainted: G E 6.18.0-rc4-00250-g2603eb907f03 #119 PREEMPT_{RT,(full [ 101.832817][ T5960] Tainted: [E]=UNSIGNED_MODULE [ 101.832819][ T5960] Hardware name: QEMU Ubuntu 25.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 101.832823][ T5960] Call Trace: [ 101.832833][ T5960] <TASK> [ 101.832838][ T5960] dump_stack_lvl+0x189/0x250 [ 101.832909][ T5960] ? __pfx_dump_stack_lvl+0x10/0x10 [ 101.832925][ T5960] ? __pfx__printk+0x10/0x10 [ 101.832934][ T5960] ? rt_mutex_slowunlock+0x493/0x8a0 [ 101.832959][ T5960] ubsan_epilogue+0xa/0x40 [ 101.832966][ T5960] __ubsan_handle_out_of_bounds+0xe9/0xf0 [ 101.833007][ T5960] dtInsertEntry+0x936/0x1430 [jfs] [ 101.833094][ T5960] dtSplitPage+0x2c8b/0x3ed0 [jfs] [ 101.833177][ T5960] ? __pfx_rt_mutex_slowunlock+0x10/0x10 [ 101.833193][ T5960] dtInsert+0x109b/0x6000 [jfs] [ 101.833283][ T5960] ? rt_mutex_slowunlock+0x493/0x8a0 [ 101.833296][ T5960] ? __pfx_rt_mutex_slowunlock+0x10/0x10 [ 101.833307][ T5960] ? rt_spin_unlock+0x161/0x200 [ 101.833315][ T5960] ? __pfx_dtInsert+0x10/0x10 [jfs] [ 101.833391][ T5960] ? txLock+0xaf9/0x1cb0 [jfs] [ 101.833477][ T5960] ? dtInitRoot+0x22a/0x670 [jfs] [ 101.833556][ T5960] jfs_mkdir+0x6ec/0xa70 [jfs] [ 101.833636][ T5960] ? __pfx_jfs_mkdir+0x10/0x10 [jfs] [ 101.833721][ T5960] ? generic_permission+0x2e5/0x690 [ 101.833760][ T5960] ? bpf_lsm_inode_mkdir+0x9/0x20 [ 101.833776][ T5960] vfs_mkdir+0x306/0x510 [ 101.833786][ T5960] do_mkdirat+0x247/0x590 [ 101.833795][ T5960] ? __pfx_do_mkdirat+0x10/0x10 [ 101.833804][ T5960] ? getname_flags+0x1e5/0x540 [ 101.833815][ T5960] __x64_sys_mkdir+0x6c/0x80 [ 101.833823][ T5960] do_syscall_64+0xfa/0xfa0 [ 101.833832][ T5960] ? lockdep_hardirqs_on+0x9c/0x150 [ 101.833840][ T5960] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 101.833847][ T5960] ? exc_page_fault+0xab/0x100 [ 101.833856][ T5960] entry_SYSCALL_64_after_hwframe+0x77/0x7f Signed-off-by: Yun Zhou <yun.zhou@windriver.com> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
1 parent 1f318b9 commit c83abc7

3 files changed

Lines changed: 92 additions & 0 deletions

File tree

‎fs/jfs/jfs_dtree.c‎

Lines changed: 86 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -4297,3 +4297,89 @@ int dtModify(tid_t tid, struct inode *ip,
42974297

42984298
return 0;
42994299
}
4300+
4301+
bool check_dtroot(dtroot_t *p)
4302+
{
4303+
DECLARE_BITMAP(bitmap, DTROOTMAXSLOT) = {0};
4304+
int i;
4305+
4306+
/* freecnt cannot be negative or exceed DTROOTMAXSLOT-1
4307+
* (since slot[0] is occupied by the header).
4308+
*/
4309+
if (unlikely(p->header.freecnt < 0 ||
4310+
p->header.freecnt > DTROOTMAXSLOT - 1)) {
4311+
jfs_err("Bad freecnt:%d in dtroot\n", p->header.freecnt);
4312+
return false;
4313+
} else if (p->header.freecnt == 0) {
4314+
/* No free slots: freelist must be -1 */
4315+
if (unlikely(p->header.freelist != -1)) {
4316+
jfs_err("freecnt=0, but freelist=%d in dtroot\n",
4317+
p->header.freelist);
4318+
return false;
4319+
}
4320+
} else {
4321+
int fsi, i;
4322+
/* When there are free slots, freelist must be a valid slot index in
4323+
* 1~DTROOTMAXSLOT-1(since slot[0] is occupied by the header).
4324+
*/
4325+
if (unlikely(p->header.freelist < 1 ||
4326+
p->header.freelist >= DTROOTMAXSLOT)) {
4327+
jfs_err("Bad freelist:%d in dtroot\n", p->header.freelist);
4328+
return false;
4329+
}
4330+
4331+
/* Traverse the free list to check validity of all node indices */
4332+
fsi = p->header.freelist;
4333+
for (i = 0; i < p->header.freecnt - 1; i++) {
4334+
/* Check for duplicate indices in the free list */
4335+
if (unlikely(__test_and_set_bit(fsi, bitmap))) {
4336+
jfs_err("duplicate index%d in slot in dtroot\n", fsi);
4337+
return false;
4338+
}
4339+
fsi = p->slot[fsi].next;
4340+
4341+
/* Ensure the next slot index in the free list is valid */
4342+
if (unlikely(fsi < 1 || fsi >= DTROOTMAXSLOT)) {
4343+
jfs_err("Bad index:%d in slot in dtroot\n", fsi);
4344+
return false;
4345+
}
4346+
}
4347+
4348+
/* The last node in the free list must terminate with next = -1 */
4349+
if (unlikely(p->slot[fsi].next != -1)) {
4350+
jfs_err("Bad next:%d of the last slot in dtroot\n",
4351+
p->slot[fsi].next);
4352+
return false;
4353+
}
4354+
}
4355+
4356+
/* Validate nextindex (next free entry index in stbl)
4357+
* stbl array has size 8 (indices 0~7).
4358+
* It may get set to 8 when the last free slot has been filled.
4359+
*/
4360+
if (unlikely(p->header.nextindex > ARRAY_SIZE(p->header.stbl))) {
4361+
jfs_err("Bad nextindex:%d in dtroot\n", p->header.nextindex);
4362+
return false;
4363+
}
4364+
4365+
/* Validate index validity of stbl array (8 elements)
4366+
* Each entry in stbl is a slot index, with valid range: -1 (invalid)
4367+
* or 0~8 (slot[0]~slot[8])
4368+
*/
4369+
for (i = 0; i < p->header.nextindex; i++) {
4370+
int idx = p->header.stbl[i];
4371+
4372+
if (unlikely(idx < 0 || idx >= 9)) {
4373+
jfs_err("Bad index:%d of stbl[%d] in dtroot\n", idx, i);
4374+
return false; /* stbl entry points out of slot array range */
4375+
}
4376+
4377+
/* Check for duplicate valid indices (skip check for idx=0) */
4378+
if (unlikely(idx && __test_and_set_bit(idx, bitmap))) {
4379+
jfs_err("Duplicate index:%d in stbl in dtroot\n", idx);
4380+
return false;
4381+
}
4382+
}
4383+
4384+
return true;
4385+
}

‎fs/jfs/jfs_dtree.h‎

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -253,4 +253,6 @@ extern int dtModify(tid_t tid, struct inode *ip, struct component_name * key,
253253
ino_t * orig_ino, ino_t new_ino, int flag);
254254

255255
extern int jfs_readdir(struct file *file, struct dir_context *ctx);
256+
257+
extern bool check_dtroot(dtroot_t *p);
256258
#endif /* !_H_JFS_DTREE */

‎fs/jfs/jfs_imap.c‎

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3102,6 +3102,10 @@ static int copy_from_dinode(struct dinode * dip, struct inode *ip)
31023102

31033103
if (S_ISDIR(ip->i_mode)) {
31043104
memcpy(&jfs_ip->u.dir, &dip->u._dir, 384);
3105+
if (!check_dtroot(&jfs_ip->i_dtroot)) {
3106+
jfs_error(ip->i_sb, "Corrupt dtroot\n");
3107+
return -EIO;
3108+
}
31053109
} else if (S_ISREG(ip->i_mode) || S_ISLNK(ip->i_mode)) {
31063110
memcpy(&jfs_ip->i_xtroot, &dip->di_xtroot, 288);
31073111
} else

0 commit comments

Comments
 (0)