CVE-2022-50255: In the Linux kernel, the following vulnerability has been resolved: tracing: Fix reading strings from synthetic events The follow commands caused a crash: # cd…

PriorityP430high7.1CVSS 3.1

AVLACLPRLUINSUCHINAH

EPSS

0.15%

4.6th percentile

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

tracing: Fix reading strings from synthetic events

The follow commands caused a crash:

# cd /sys/kernel/tracing
# echo 's:open char file[]' > dynamic_events
# echo 'hist:keys=common_pid:file=filename:onchange($file).trace(open,$file)' > events/syscalls/sys_enter_openat/trigger'
# echo 1 > events/synthetic/open/enable

BOOM!

The problem is that the synthetic event field "char file[]" will read
the value given to it as a string without any memory checks to make sure
the address is valid. The above example will pass in the user space
address and the sythetic event code will happily call strlen() on it
and then strscpy() where either one will cause an oops when accessing
user space addresses.

Use the helper functions from trace_kprobe and trace_eprobe that can
read strings safely (and actually succeed when the address is from user
space and the memory is mapped in).

Now the above can show:

packagekitd-1721 [000] ...2. 104.597170: open: file=/usr/lib/rpm/fileattrs/cmake.attr
in:imjournal-978 [006] ...2. 104.599642: open: file=/var/lib/rsyslog/imjournal.state.tmp
packagekitd-1721 [000] ...2. 104.626308: open: file=/usr/lib/rpm/fileattrs/debuginfo.attr

Affected

12 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 6.0.3-1 (bookworm)	linux 6.0.3-1 (bookworm)
linux	linux	—	—
linux	linux	>= bd82631d7ccdc894af2738e47abcba2cb6e7dea9 < d9c79fbcbdb6cb10c07c85040eaf615180b26c48	d9c79fbcbdb6cb10c07c85040eaf615180b26c48
linux	linux	>= bd82631d7ccdc894af2738e47abcba2cb6e7dea9 < 149198d0b884e4606ed1d29b330c70016d878276	149198d0b884e4606ed1d29b330c70016d878276
linux	linux	>= bd82631d7ccdc894af2738e47abcba2cb6e7dea9 < f8bae1853196b52ede50950387f5b48cf83b9815	f8bae1853196b52ede50950387f5b48cf83b9815
linux	linux	>= bd82631d7ccdc894af2738e47abcba2cb6e7dea9 < 0934ae9977c27133449b6dd8c6213970e7eece38	0934ae9977c27133449b6dd8c6213970e7eece38
linux	linux_kernel	>= 0 < 6.0.3-1	6.0.3-1
linux	linux_kernel	>= 0 < 6.0.3-1	6.0.3-1
linux	linux_kernel	>= 0 < 6.0.3-1	6.0.3-1
linux	linux_kernel	>= 5.10 < 5.15.75	5.15.75
linux	linux_kernel	>= 5.16 < 5.19.17	5.19.17
linux	linux_kernel	>= 6.0 < 6.0.3	6.0.3

CVSS provenance

nvdv3.17.1HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

osv7.1HIGH

vendor_debian7.1HIGH

vendor_redhat7.1HIGH

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