diff options
| author | Denis Efremov <efremov@ispras.ru> | 2019-07-12 21:55:22 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2019-08-13 12:39:26 +0100 |
| commit | fbf6a95d0a3d410ee2f4530e243b77beee87c76a (patch) | |
| tree | 9066552e20bb38ab12b6b61c0f07bee2775a8bcf | |
| parent | 59fbdf8b65a4f09d8043dded8a4b8e0d603eee27 (diff) | |
floppy: fix invalid pointer dereference in drive_name
commit 9b04609b784027968348796a18f601aed9db3789 upstream.
This fixes the invalid pointer dereference in the drive_name function of
the floppy driver.
The native_format field of the struct floppy_drive_params is used as
floppy_type array index in the drive_name function. Thus, the field
should be checked the same way as the autodetect field.
To trigger the bug, one could use a value out of range and set the drive
parameters with the FDSETDRVPRM ioctl. Next, FDGETDRVTYP ioctl should
be used to call the drive_name. A floppy disk is not required to be
inserted.
CAP_SYS_ADMIN is required to call FDSETDRVPRM.
The patch adds the check for a value of the native_format field to be in
the '0 <= x < ARRAY_SIZE(floppy_type)' range of the floppy_type array
indices.
The bug was found by syzkaller.
Signed-off-by: Denis Efremov <efremov@ispras.ru>
Tested-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.16: Drop changes in compat_setdrvprm(), as compat
ioctls go via fd_ioctl_locked() after translation in compat_ioctl.c.]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | drivers/block/floppy.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 7345154fde581..2d6087bb3bc4e 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -3383,7 +3383,8 @@ static int fd_getgeo(struct block_device *bdev, struct hd_geometry *geo) return 0; } -static bool valid_floppy_drive_params(const short autodetect[8]) +static bool valid_floppy_drive_params(const short autodetect[8], + int native_format) { size_t floppy_type_size = ARRAY_SIZE(floppy_type); size_t i = 0; @@ -3394,6 +3395,9 @@ static bool valid_floppy_drive_params(const short autodetect[8]) return false; } + if (native_format < 0 || native_format >= floppy_type_size) + return false; + return true; } @@ -3523,7 +3527,8 @@ static int fd_locked_ioctl(struct block_device *bdev, fmode_t mode, unsigned int SUPBOUND(size, strlen((const char *)outparam) + 1); break; case FDSETDRVPRM: - if (!valid_floppy_drive_params(inparam.dp.autodetect)) + if (!valid_floppy_drive_params(inparam.dp.autodetect, + inparam.dp.native_format)) return -EINVAL; *UDP = inparam.dp; break; |