| Message ID | 20221021102157.1341807-2-lizetao1@huawei.com |
|---|---|
| State | Accepted |
| Delegated to: | Richard Weinberger |
| Headers | show |
| Series | Fix use-after-free and kmemleak in ubi_resize_volume() | expand |
在 2022/10/21 18:21, Li Zetao 写道: > There is an use-after-free problem reported by KASAN: > ================================================================== > BUG: KASAN: use-after-free in ubi_eba_copy_table+0x11f/0x1c0 [ubi] > Read of size 8 at addr ffff888101eec008 by task ubirsvol/4735 > > CPU: 2 PID: 4735 Comm: ubirsvol > Not tainted 6.1.0-rc1-00003-g84fa3304a7fc-dirty #14 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), > BIOS 1.14.0-1.fc33 04/01/2014 > Call Trace: > <TASK> > dump_stack_lvl+0x34/0x44 > print_report+0x171/0x472 > kasan_report+0xad/0x130 > ubi_eba_copy_table+0x11f/0x1c0 [ubi] > ubi_resize_volume+0x4f9/0xbc0 [ubi] > ubi_cdev_ioctl+0x701/0x1850 [ubi] > __x64_sys_ioctl+0x11d/0x170 > do_syscall_64+0x35/0x80 > entry_SYSCALL_64_after_hwframe+0x46/0xb0 > </TASK> > > When ubi_change_vtbl_record() returns an error in ubi_resize_volume(), > "new_eba_tbl" will be freed on error handing path, but it is holded > by "vol->eba_tbl" in ubi_eba_replace_table(). It means that the liftcycle > of "vol->eba_tbl" and "vol" are different, so when resizing volume in > next time, it causing an use-after-free fault. > > Fix it by not freeing "new_eba_tbl" after it replaced in > ubi_eba_replace_table(), while will be freed in next volume resizing. > > Fixes: 801c135ce73d ("UBI: Unsorted Block Images") > Signed-off-by: Li Zetao <lizetao1@huawei.com> > --- > drivers/mtd/ubi/vmt.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c > index 8fcc0bdf0635..74637575346e 100644 > --- a/drivers/mtd/ubi/vmt.c > +++ b/drivers/mtd/ubi/vmt.c > @@ -464,7 +464,7 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs) > for (i = 0; i < -pebs; i++) { > err = ubi_eba_unmap_leb(ubi, vol, reserved_pebs + i); > if (err) > - goto out_acc; > + goto out_free; > } > spin_lock(&ubi->volumes_lock); > ubi->rsvd_pebs += pebs; > @@ -512,6 +512,8 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs) > ubi->avail_pebs += pebs; > spin_unlock(&ubi->volumes_lock); > } > + return err; > + > out_free: > kfree(new_eba_tbl); > return err; Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c index 8fcc0bdf0635..74637575346e 100644 --- a/drivers/mtd/ubi/vmt.c +++ b/drivers/mtd/ubi/vmt.c @@ -464,7 +464,7 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs) for (i = 0; i < -pebs; i++) { err = ubi_eba_unmap_leb(ubi, vol, reserved_pebs + i); if (err) - goto out_acc; + goto out_free; } spin_lock(&ubi->volumes_lock); ubi->rsvd_pebs += pebs; @@ -512,6 +512,8 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs) ubi->avail_pebs += pebs; spin_unlock(&ubi->volumes_lock); } + return err; + out_free: kfree(new_eba_tbl); return err;
There is an use-after-free problem reported by KASAN: ================================================================== BUG: KASAN: use-after-free in ubi_eba_copy_table+0x11f/0x1c0 [ubi] Read of size 8 at addr ffff888101eec008 by task ubirsvol/4735 CPU: 2 PID: 4735 Comm: ubirsvol Not tainted 6.1.0-rc1-00003-g84fa3304a7fc-dirty #14 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x34/0x44 print_report+0x171/0x472 kasan_report+0xad/0x130 ubi_eba_copy_table+0x11f/0x1c0 [ubi] ubi_resize_volume+0x4f9/0xbc0 [ubi] ubi_cdev_ioctl+0x701/0x1850 [ubi] __x64_sys_ioctl+0x11d/0x170 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 </TASK> When ubi_change_vtbl_record() returns an error in ubi_resize_volume(), "new_eba_tbl" will be freed on error handing path, but it is holded by "vol->eba_tbl" in ubi_eba_replace_table(). It means that the liftcycle of "vol->eba_tbl" and "vol" are different, so when resizing volume in next time, it causing an use-after-free fault. Fix it by not freeing "new_eba_tbl" after it replaced in ubi_eba_replace_table(), while will be freed in next volume resizing. Fixes: 801c135ce73d ("UBI: Unsorted Block Images") Signed-off-by: Li Zetao <lizetao1@huawei.com> --- drivers/mtd/ubi/vmt.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)