CVE-2023-53783: In the Linux kernel, the following vulnerability has been resolved: blk-iocost: fix divide by 0 error in calc_lcoefs() echo max of u64 to cost.model can cause…

PriorityP419medium5.5

EPSS

0.20%

10.2th percentile

In the Linux kernel, the following vulnerability has been resolved:

blk-iocost: fix divide by 0 error in calc_lcoefs()

echo max of u64 to cost.model can cause divide by 0 error.

# echo 8:0 rbps=18446744073709551615 > /sys/fs/cgroup/io.cost.model

divide error: 0000 [#1] PREEMPT SMP
RIP: 0010:calc_lcoefs+0x4c/0xc0
Call Trace:

ioc_refresh_params+0x2b3/0x4f0
ioc_cost_model_write+0x3cb/0x4c0
? _copy_from_iter+0x6d/0x6c0
? kernfs_fop_write_iter+0xfc/0x270
cgroup_file_write+0xa0/0x200
kernfs_fop_write_iter+0x17d/0x270
vfs_write+0x414/0x620
ksys_write+0x73/0x160
__x64_sys_write+0x1e/0x30
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

calc_lcoefs() uses the input value of cost.model in DIV_ROUND_UP_ULL,
overflow would happen if bps plus IOC_PAGE_SIZE is greater than
ULLONG_MAX, it can cause divide by 0 error.

Fix the problem by setting basecost

Affected

17 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 6.1.20-1 (bookworm)	linux 6.1.20-1 (bookworm)
linux	linux	—	—
linux	linux	>= 7caa47151ab2e644dd221f741ec7578d9532c9a3 < 9e8bf9f95f7a299fa9ea45b678d001806ad5e12c	9e8bf9f95f7a299fa9ea45b678d001806ad5e12c
linux	linux	>= 7caa47151ab2e644dd221f741ec7578d9532c9a3 < 6e291810fe83a384700eb24a1f714966391ed562	6e291810fe83a384700eb24a1f714966391ed562
linux	linux	>= 7caa47151ab2e644dd221f741ec7578d9532c9a3 < 3538ade9d8c2ba41088e395de916f2599fadba8f	3538ade9d8c2ba41088e395de916f2599fadba8f
linux	linux	>= 7caa47151ab2e644dd221f741ec7578d9532c9a3 < bf8eb1fd6110871e6232e8e7efe399276ef7e6f6	bf8eb1fd6110871e6232e8e7efe399276ef7e6f6
linux	linux	>= 7caa47151ab2e644dd221f741ec7578d9532c9a3 < b96d7b4a9745fbd0c8384608ceb1f50415e862fa	b96d7b4a9745fbd0c8384608ceb1f50415e862fa
linux	linux	>= 7caa47151ab2e644dd221f741ec7578d9532c9a3 < 984af1e66b4126cf145153661cc24c213e2ec231	984af1e66b4126cf145153661cc24c213e2ec231
linux	linux_kernel	>= 0 < 5.10.178-1	5.10.178-1
linux	linux_kernel	>= 0 < 6.1.20-1	6.1.20-1
linux	linux_kernel	>= 0 < 6.1.20-1	6.1.20-1
linux	linux_kernel	>= 0 < 6.1.20-1	6.1.20-1
linux	linux_kernel	>= 5.11.0 < 5.15.99	5.15.99
linux	linux_kernel	>= 5.16.0 < 6.1.16	6.1.16
linux	linux_kernel	>= 5.4.0 < 5.4.235	5.4.235
linux	linux_kernel	>= 5.5.0 < 5.10.173	5.10.173
linux	linux_kernel	>= 6.2.0 < 6.2.3	6.2.3

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