CVE-2021-47192

NameCVE-2021-47192
DescriptionIn the Linux kernel, the following vulnerability has been resolved: scsi: core: sysfs: Fix hang when device state is set via sysfs This fixes a regression added with: commit f0f82e2476f6 ("scsi: core: Fix capacity set to zero after offlinining device") The problem is that after iSCSI recovery, iscsid will call into the kernel to set the dev's state to running, and with that patch we now call scsi_rescan_device() with the state_mutex held. If the SCSI error handler thread is just starting to test the device in scsi_send_eh_cmnd() then it's going to try to grab the state_mutex. We are then stuck, because when scsi_rescan_device() tries to send its I/O scsi_queue_rq() calls -> scsi_host_queue_ready() -> scsi_host_in_recovery() which will return true (the host state is still in recovery) and I/O will just be requeued. scsi_send_eh_cmnd() will then never be able to grab the state_mutex to finish error handling. To prevent the deadlock move the rescan-related code to after we drop the state_mutex. This also adds a check for if we are already in the running state. This prevents extra scans and helps the iscsid case where if the transport class has already onlined the device during its recovery process then we don't need userspace to do it again plus possibly block that daemon.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)buster4.19.249-2fixed
buster (security)4.19.304-1fixed
bullseye5.10.209-2fixed
bullseye (security)5.10.216-1fixed
bookworm6.1.76-1fixed
bookworm (security)6.1.90-1fixed
trixie6.7.12-1fixed
sid6.8.9-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcebuster(not affected)
linuxsourcebullseye5.10.84-1
linuxsource(unstable)5.15.5-1

Notes

[buster] - linux <not-affected> (Vulnerable code not present)
https://git.kernel.org/linus/4edd8cd4e86dd3047e5294bbefcc0a08f66a430f (5.16-rc2)

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