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| author | Justin Stitt <justinstitt@google.com> | 2024-05-08 17:22:51 +0000 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2024-05-15 10:05:24 -0400 |
| commit | 9fad9d560af5c654bb38e0b07ee54a4e9acdc5cd (patch) | |
| tree | 7ef449104d15113be3396bee32fcbae6b97c27d6 /Documentation/cdrom | |
| parent | 10157b1fc1a762293381e9145041253420dfc6ad (diff) | |
| download | linux-9fad9d560af5c654bb38e0b07ee54a4e9acdc5cd.tar.gz linux-9fad9d560af5c654bb38e0b07ee54a4e9acdc5cd.tar.bz2 linux-9fad9d560af5c654bb38e0b07ee54a4e9acdc5cd.zip | |
scsi: sr: Fix unintentional arithmetic wraparound
Running syzkaller with the newly reintroduced signed integer overflow
sanitizer produces this report:
[ 65.194362] ------------[ cut here ]------------
[ 65.197752] UBSAN: signed-integer-overflow in ../drivers/scsi/sr_ioctl.c:436:9
[ 65.203607] -2147483648 * 177 cannot be represented in type 'int'
[ 65.207911] CPU: 2 PID: 10416 Comm: syz-executor.1 Not tainted 6.8.0-rc2-00035-gb3ef86b5a957 #1
[ 65.213585] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 65.219923] Call Trace:
[ 65.221556] <TASK>
[ 65.223029] dump_stack_lvl+0x93/0xd0
[ 65.225573] handle_overflow+0x171/0x1b0
[ 65.228219] sr_select_speed+0xeb/0xf0
[ 65.230786] ? __pm_runtime_resume+0xe6/0x130
[ 65.233606] sr_block_ioctl+0x15d/0x1d0
...
Historically, the signed integer overflow sanitizer did not work in the
kernel due to its interaction with `-fwrapv` but this has since been
changed [1] in the newest version of Clang. It was re-enabled in the kernel
with Commit 557f8c582a9b ("ubsan: Reintroduce signed overflow sanitizer").
Firstly, let's change the type of "speed" to unsigned long as
sr_select_speed()'s only caller passes in an unsigned long anyways.
$ git grep '\.select_speed'
| drivers/scsi/sr.c: .select_speed = sr_select_speed,
...
| static int cdrom_ioctl_select_speed(struct cdrom_device_info *cdi,
| unsigned long arg)
| {
| ...
| return cdi->ops->select_speed(cdi, arg);
| }
Next, let's add an extra check to make sure we don't exceed 0xffff/177
(350) since 0xffff is the max speed. This has two benefits: 1) we deal
with integer overflow before it happens and 2) we properly respect the
max speed of 0xffff. There are some "magic" numbers here but I did not
want to change more than what was necessary.
Link: https://github.com/llvm/llvm-project/pull/82432 [1]
Closes: https://github.com/KSPP/linux/issues/357
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240508-b4-b4-sio-sr_select_speed-v2-1-00b68f724290@google.com
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'Documentation/cdrom')
| -rw-r--r-- | Documentation/cdrom/cdrom-standard.rst | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/Documentation/cdrom/cdrom-standard.rst b/Documentation/cdrom/cdrom-standard.rst index 7964fe134277..6c1303cff159 100644 --- a/Documentation/cdrom/cdrom-standard.rst +++ b/Documentation/cdrom/cdrom-standard.rst @@ -217,7 +217,7 @@ current *struct* is:: int (*media_changed)(struct cdrom_device_info *, int); int (*tray_move)(struct cdrom_device_info *, int); int (*lock_door)(struct cdrom_device_info *, int); - int (*select_speed)(struct cdrom_device_info *, int); + int (*select_speed)(struct cdrom_device_info *, unsigned long); int (*get_last_session) (struct cdrom_device_info *, struct cdrom_multisession *); int (*get_mcn)(struct cdrom_device_info *, struct cdrom_mcn *); @@ -396,7 +396,7 @@ action need be taken, and the return value should be 0. :: - int select_speed(struct cdrom_device_info *cdi, int speed) + int select_speed(struct cdrom_device_info *cdi, unsigned long speed) Some CD-ROM drives are capable of changing their head-speed. There are several reasons for changing the speed of a CD-ROM drive. Badly |