Messages in this thread | | | Date | Wed, 28 Sep 2022 23:45:18 +0200 | Subject | Re: KASAN: use-after-free Read in sg_release | From | Douglas Gilbert <> |
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On 2022-09-22 17:29, Tony Battersby wrote: > On 9/20/22 10:46, Rondreis wrote: >> Hello, >> >> When fuzzing the Linux kernel driver v6.0-rc6, the following crash was >> triggered. >> >> HEAD commit: 521a547ced6477c54b4b0cc206000406c221b4d6 >> git tree: upstream >> >> kernel config: https://pastebin.com/raw/hekxU61F >> console output: https://pastebin.com/raw/73a8RzBY >> >> Sorry for failing to extract the reproducer. But on other versions of >> Linux, I also triggered this crash. >> >> I would appreciate it if you have any idea how to solve this bug. >> > sg_release() calls "kref_put(&sfp->f_ref, sg_remove_sfp)" which > eventually does "kref_put(&sdp->d_ref, sg_device_destroy)" which does > "kfree(sdp)", but sg_release() continues to access sdp afterward. Try > the following patch. > >>From 82ca6785c40eded6229183a53752fc5e43db4a94 Mon Sep 17 00:00:00 2001 > From: Tony Battersby <tonyb@cybernetics.com> > Date: Thu, 22 Sep 2022 11:05:30 -0400 > Subject: [PATCH] scsi: sg: fix memory-use-after-free on device removal > > Fix memory-use-after-free race when closing a sg fd to a removed device. > > Link: https://lore.kernel.org/linux-scsi/CAB7eexK_jr1LWOO9RWrBF9as7gAS9kpHjrZFRuRrRJF=1H4W6A@mail.gmail.com/ > Reported-by: Rondreis <linhaoguo86@gmail.com> > Cc: <stable@vger.kernel.org> > Signed-off-by: Tony Battersby <tonyb@cybernetics.com> > --- > drivers/scsi/sg.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c > index 340b050ad28d..f44cbe42dba9 100644 > --- a/drivers/scsi/sg.c > +++ b/drivers/scsi/sg.c > @@ -388,6 +388,7 @@ sg_release(struct inode *inode, struct file *filp) > return -ENXIO; > SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp, "sg_release\n")); > > + kref_get(&sdp->d_ref); > mutex_lock(&sdp->open_rel_lock); > scsi_autopm_put_device(sdp->device); > kref_put(&sfp->f_ref, sg_remove_sfp); > @@ -402,6 +403,7 @@ sg_release(struct inode *inode, struct file *filp) > wake_up_interruptible(&sdp->open_wait); > } > mutex_unlock(&sdp->open_rel_lock); > + kref_put(&sdp->d_ref, sg_device_destroy); > return 0; > } >
Hi Rondreis, Have you been able to test the above patch from Tony?
Doug Gilbert
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