Re: [PATCH] scsi: Fix a use after free in st_open
From: "Kai Mäkisara (Kolumbus)" <kai.makisara@kolumbus.fi>
Date: 2021-03-11 18:27:20
Also in:
lkml
On 11. Mar 2021, at 8.46, Lv Yunlong [off-list ref] wrote: In st_open, if STp->in_use is true, STp will be freed by scsi_tape_put(). However, STp is still used by DEBC_printk() after. It is better to DEBC_printk() before scsi_tape_put(). Signed-off-by: Lv Yunlong <redacted>
Acked-by: Kai Mäkisara <kai.makisara@kolumbus.fi>
quoted hunk ↗ jump to hunk
--- drivers/scsi/st.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c index 841ad2fc369a..9ca536aae784 100644 --- a/drivers/scsi/st.c +++ b/drivers/scsi/st.c@@ -1269,8 +1269,8 @@ static int st_open(struct inode *inode, struct file *filp)spin_lock(&st_use_lock); if (STp->in_use) { spin_unlock(&st_use_lock); - scsi_tape_put(STp); DEBC_printk(STp, "Device already in use.\n"); + scsi_tape_put(STp); return (-EBUSY); }
Potential problem only when debugging enabled, but should be fixed. Thanks, Kai