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commit 014bcf41d946b36a8f0b8e9b5d9529efbb822f49 upstream. The isd200 sub-driver in usb-storage uses the HEADS and SECTORS values in the ATA ID information to calculate cylinder and head values when creating a CDB for READ or WRITE commands. The calculation involves division and modulus operations, which will cause a crash if either of these values is 0. While this never happens with a genuine device, it could happen with a flawed or subversive emulation, as reported by the syzbot fuzzer. Protect against this possibility by refusing to bind to the device if either the ATA_ID_HEADS or ATA_ID_SECTORS value in the device's ID information is 0. This requires isd200_Initialization() to return a negative error code when initialization fails; currently it always returns 0 (even when there is an error). Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-and-tested-by: syzbot+28748250ab47a8f04100@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-usb/0000000000003eb868061245ba7f@google.com/ Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://lore.kernel.org/r/b1e605ea-333f-4ac0-9511-da04f411763e@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.