| Name | CVE-2021-47343 |
| Description | In the Linux kernel, the following vulnerability has been resolved:
dm btree remove: assign new_root only when removal succeeds
remove_raw() in dm_btree_remove() may fail due to IO read error
(e.g. read the content of origin block fails during shadowing),
and the value of shadow_spine::root is uninitialized, but
the uninitialized value is still assign to new_root in the
end of dm_btree_remove().
For dm-thin, the value of pmd->details_root or pmd->root will become
an uninitialized value, so if trying to read details_info tree again
out-of-bound memory may occur as showed below:
general protection fault, probably for non-canonical address 0x3fdcb14c8d7520
CPU: 4 PID: 515 Comm: dmsetup Not tainted 5.13.0-rc6
Hardware name: QEMU Standard PC
RIP: 0010:metadata_ll_load_ie+0x14/0x30
Call Trace:
sm_metadata_count_is_more_than_one+0xb9/0xe0
dm_tm_shadow_block+0x52/0x1c0
shadow_step+0x59/0xf0
remove_raw+0xb2/0x170
dm_btree_remove+0xf4/0x1c0
dm_pool_delete_thin_device+0xc3/0x140
pool_message+0x218/0x2b0
target_message+0x251/0x290
ctl_ioctl+0x1c4/0x4d0
dm_ctl_ioctl+0xe/0x20
__x64_sys_ioctl+0x7b/0xb0
do_syscall_64+0x40/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae
Fixing it by only assign new_root when removal succeeds |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
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The information below is based on the following data on fixed versions.