Описание
In the Linux kernel, the following vulnerability has been resolved:
dm-io: clone the source bio instead of copying its biovec
For DM_IO_BIO requests, do_region() built each destination bio by walking
the source bio's biovec and re-adding the pages one at a time, tracking
the remaining transfer in sectors. The vector lengths are byte granular
and need not be sector aligned (e.g. a misaligned O_DIRECT buffer split
across pages), so the sector-based accounting could lose a sub-sector
fragment: to_sector() truncated the remainder and the outer loop spun
forever submitting empty bios, hanging the I/O.
There is no need to rebuild the biovec at all. The destination reads into
(or writes from) exactly the same pages as the source bio, so the bio can
simply clone the source's biovec with bio_alloc_clone() and remap it to
the target device. The clone inherits the source's iterator and alignment,
and the block layer splits it to the target's limits on submission, so the
whole region maps to a single cloned bio with no manual page copying or
sector accounting.
This removes the per-page copy path (and its open-coded bvec dpages
helpers) for bio-backed I/O and fixes the hang on misaligned direct I/O to
a dm-mirror device. Page-list, vma and kmem sources keep the existing copy
path.
A flaw was found in the Linux kernel's device mapper I/O (dm-io) component. When handling DM_IO_BIO requests, incorrect sector-based accounting for misaligned direct I/O buffers could lead to an infinite loop. This issue can cause I/O operations to hang indefinitely, resulting in a denial of service (DoS) for the affected system. A local attacker could exploit this by performing specific misaligned direct I/O operations to a dm-mirror device.
Ссылки на источники
Дополнительная информация
Статус:
4.1 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: dm-io: clone the source bio instead of copying its biovec For DM_IO_BIO requests, do_region() built each destination bio by walking the source bio's biovec and re-adding the pages one at a time, tracking the remaining transfer in sectors. The vector lengths are byte granular and need not be sector aligned (e.g. a misaligned O_DIRECT buffer split across pages), so the sector-based accounting could lose a sub-sector fragment: to_sector() truncated the remainder and the outer loop spun forever submitting empty bios, hanging the I/O. There is no need to rebuild the biovec at all. The destination reads into (or writes from) exactly the same pages as the source bio, so the bio can simply clone the source's biovec with bio_alloc_clone() and remap it to the target device. The clone inherits the source's iterator and alignment, and the block layer splits it to the target's limits on submission, so the whole region maps to a ...
In the Linux kernel, the following vulnerability has been resolved: dm-io: clone the source bio instead of copying its biovec For DM_IO_BIO requests, do_region() built each destination bio by walking the source bio's biovec and re-adding the pages one at a time, tracking the remaining transfer in sectors. The vector lengths are byte granular and need not be sector aligned (e.g. a misaligned O_DIRECT buffer split across pages), so the sector-based accounting could lose a sub-sector fragment: to_sector() truncated the remainder and the outer loop spun forever submitting empty bios, hanging the I/O. There is no need to rebuild the biovec at all. The destination reads into (or writes from) exactly the same pages as the source bio, so the bio can simply clone the source's biovec with bio_alloc_clone() and remap it to the target device. The clone inherits the source's iterator and alignment, and the block layer splits it to the target's limits on submission, so the whole region maps to a
In the Linux kernel, the following vulnerability has been resolved: d ...
In the Linux kernel, the following vulnerability has been resolved: dm-io: clone the source bio instead of copying its biovec For DM_IO_BIO requests, do_region() built each destination bio by walking the source bio's biovec and re-adding the pages one at a time, tracking the remaining transfer in sectors. The vector lengths are byte granular and need not be sector aligned (e.g. a misaligned O_DIRECT buffer split across pages), so the sector-based accounting could lose a sub-sector fragment: to_sector() truncated the remainder and the outer loop spun forever submitting empty bios, hanging the I/O. There is no need to rebuild the biovec at all. The destination reads into (or writes from) exactly the same pages as the source bio, so the bio can simply clone the source's biovec with bio_alloc_clone() and remap it to the target device. The clone inherits the source's iterator and alignment, and the block layer splits it to the target's limits on submission, so the whole region maps to...
4.1 Medium
CVSS3