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authorPete Zaitcev <zaitcev@redhat.com>2018-01-09 00:46:41 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-01-09 18:06:53 +0300
commit46eb14a6e1585d99c1b9f58d0e7389082a5f466b (patch)
tree6e023a773c858245b4ceca196ec093ad5a9b7298 /drivers/usb
parent5fd77a3a0e408c23ab4002a57db980e46bc16e72 (diff)
downloadlinux-46eb14a6e1585d99c1b9f58d0e7389082a5f466b.tar.xz
USB: fix usbmon BUG trigger
Automated tests triggered this by opening usbmon and accessing the mmap while simultaneously resizing the buffers. This bug was with us since 2006, because typically applications only size the buffers once and thus avoid racing. Reported by Kirill A. Shutemov. Reported-by: <syzbot+f9831b881b3e849829fc@syzkaller.appspotmail.com> Signed-off-by: Pete Zaitcev <zaitcev@redhat.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb')
-rw-r--r--drivers/usb/mon/mon_bin.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/usb/mon/mon_bin.c b/drivers/usb/mon/mon_bin.c
index f6ae753ab99b..f932f40302df 100644
--- a/drivers/usb/mon/mon_bin.c
+++ b/drivers/usb/mon/mon_bin.c
@@ -1004,7 +1004,9 @@ static long mon_bin_ioctl(struct file *file, unsigned int cmd, unsigned long arg
break;
case MON_IOCQ_RING_SIZE:
+ mutex_lock(&rp->fetch_lock);
ret = rp->b_size;
+ mutex_unlock(&rp->fetch_lock);
break;
case MON_IOCT_RING_SIZE:
@@ -1231,12 +1233,16 @@ static int mon_bin_vma_fault(struct vm_fault *vmf)
unsigned long offset, chunk_idx;
struct page *pageptr;
+ mutex_lock(&rp->fetch_lock);
offset = vmf->pgoff << PAGE_SHIFT;
- if (offset >= rp->b_size)
+ if (offset >= rp->b_size) {
+ mutex_unlock(&rp->fetch_lock);
return VM_FAULT_SIGBUS;
+ }
chunk_idx = offset / CHUNK_SIZE;
pageptr = rp->b_vec[chunk_idx].pg;
get_page(pageptr);
+ mutex_unlock(&rp->fetch_lock);
vmf->page = pageptr;
return 0;
}