kernel/linux.git/drivers/block/floppy.c, branch v4.4.239

floppy: check FDC index for errors before assigning it

2020-02-28T14:39:11+00:00

commit 2e90ca68b0d2f5548804f22f0dd61145516171e3 upstream. Jordy Zomer reported a KASAN out-of-bounds read in the floppy driver in wait_til_ready(). Which on the face of it can't happen, since as Willy Tarreau points out, the function does no particular memory access. Except through the FDCS macro, which just indexes a static allocation through teh current fdc, which is always checked against N_FDC. Except the checking happens after we've already assigned the value. The floppy driver is a disgrace (a lot of it going back to my original horrd "design"), and has no real maintainer. Nobody has the hardware, and nobody really cares. But it still gets used in virtual environment because it's one of those things that everybody supports. The whole thing should be re-written, or at least parts of it should be seriously cleaned up. The 'current fdc' index, which is used by the FDCS macro, and which is often shadowed by a local 'fdc' variable, is a prime example of how not to write code. But because nobody has the hardware or the motivation, let's just fix up the immediate problem with a nasty band-aid: test the fdc index before actually assigning it to the static 'fdc' variable. Reported-by: Jordy Zomer Cc: Willy Tarreau Cc: Dan Carpenter Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

floppy: fix usercopy direction

2019-09-21T05:12:53+00:00

commit 52f6f9d74f31078964ca1574f7bb612da7877ac8 upstream. As sparse points out, these two copy_from_user() should actually be copy_to_user(). Fixes: 229b53c9bf4e ("take floppy compat ioctls to sodding floppy.c") Cc: stable@vger.kernel.org Acked-by: Alexander Popov Reviewed-by: Mukesh Ojha Signed-off-by: Jann Horn Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

floppy: fix out-of-bounds read in copy_buffer

2019-08-04T07:34:52+00:00

[ Upstream commit da99466ac243f15fbba65bd261bfc75ffa1532b6 ] This fixes a global out-of-bounds read access in the copy_buffer function of the floppy driver. The FDDEFPRM ioctl allows one to set the geometry of a disk. The sect and head fields (unsigned int) of the floppy_drive structure are used to compute the max_sector (int) in the make_raw_rw_request function. It is possible to overflow the max_sector. Next, max_sector is passed to the copy_buffer function and used in one of the memcpy calls. An unprivileged user could trigger the bug if the device is accessible, but requires a floppy disk to be inserted. The patch adds the check for the .sect * .head multiplication for not overflowing in the set_geometry function. The bug was found by syzkaller. Signed-off-by: Denis Efremov Tested-by: Willy Tarreau Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

floppy: fix invalid pointer dereference in drive_name

2019-08-04T07:34:52+00:00

[ Upstream commit 9b04609b784027968348796a18f601aed9db3789 ] 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 Tested-by: Willy Tarreau Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

floppy: fix out-of-bounds read in next_valid_format

2019-08-04T07:34:52+00:00

[ Upstream commit 5635f897ed83fd539df78e98ba69ee91592f9bb8 ] This fixes a global out-of-bounds read access in the next_valid_format function of the floppy driver. The values from autodetect field of the struct floppy_drive_params are used as indices for the floppy_type array in the next_valid_format function 'floppy_type[DP->autodetect[probed_format]].sect'. To trigger the bug, one could use a value out of range and set the drive parameters with the FDSETDRVPRM ioctl. A floppy disk is not required to be inserted. CAP_SYS_ADMIN is required to call FDSETDRVPRM. The patch adds the check for values of the autodetect 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 Tested-by: Willy Tarreau Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

floppy: fix div-by-zero in setup_format_params

2019-08-04T07:34:51+00:00

[ Upstream commit f3554aeb991214cbfafd17d55e2bfddb50282e32 ] This fixes a divide by zero error in the setup_format_params function of the floppy driver. Two consecutive ioctls can trigger the bug: The first one should set the drive geometry with such .sect and .rate values for the F_SECT_PER_TRACK to become zero. Next, the floppy format operation should be called. A floppy disk is not required to be inserted. An unprivileged user could trigger the bug if the device is accessible. The patch checks F_SECT_PER_TRACK for a non-zero value in the set_geometry function. The proper check should involve a reasonable upper limit for the .sect and .rate fields, but it could change the UAPI. The patch also checks F_SECT_PER_TRACK in the setup_format_params, and cancels the formatting operation in case of zero. The bug was found by syzkaller. Signed-off-by: Denis Efremov Tested-by: Willy Tarreau Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

take floppy compat ioctls to sodding floppy.c

2019-08-04T07:34:51+00:00

[ Upstream commit 229b53c9bf4e1132a4aa6feb9632a7a1f1d08c5c ] all other drivers recognizing those ioctls are very much *not* biarch. Signed-off-by: Al Viro Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

floppy: Do not copy a kernel pointer to user memory in FDGETPRM ioctl

2018-10-10T06:52:07+00:00

commit 65eea8edc315589d6c993cf12dbb5d0e9ef1fe4e upstream. The final field of a floppy_struct is the field "name", which is a pointer to a string in kernel memory. The kernel pointer should not be copied to user memory. The FDGETPRM ioctl copies a floppy_struct to user memory, including this "name" field. This pointer cannot be used by the user and it will leak a kernel address to user-space, which will reveal the location of kernel code and data and undermine KASLR protection. Model this code after the compat ioctl which copies the returned data to a previously cleared temporary structure on the stack (excluding the name pointer) and copy out to userspace from there. As we already have an inparam union with an appropriate member and that memory is already cleared even for read only calls make use of that as a temporary store. Based on an initial patch by Brian Belleville. CVE-2018-7755 Signed-off-by: Andy Whitcroft Broke up long line. Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block: add a bi_error field to struct bio

2015-07-29T14:55:15+00:00

Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Reviewed-by: NeilBrown Signed-off-by: Jens Axboe

floppy: Avoid manual call of device_create_file()

2015-02-03T12:00:36+00:00

Use the static attribute groups assigned to the device instead of calling device_create_file() after the device registration. Signed-off-by: Takashi Iwai Signed-off-by: Jiri Kosina