In the Linux kernel, the following vulnerability has been resolved:
tracing: Have trace_event_file have ref counters The following can crash
the kernel: # cd /sys/kernel/tracing # echo ‘p:sched schedule’ >
kprobe_events # exec 5>>events/kprobes/sched/enable # > kprobe_events #
exec 5>&- The above commands: 1. Change directory to the tracefs directory
2. Create a kprobe event (doesn’t matter what one) 3. Open bash file
descriptor 5 on the enable file of the kprobe event 4. Delete the kprobe
event (removes the files too) 5. Close the bash file descriptor 5 The above
causes a crash! BUG: kernel NULL pointer dereference, address:
0000000000000028 #PF: supervisor read access in kernel mode #PF:
error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT
SMP PTI CPU: 6 PID: 877 Comm: bash Not tainted
6.5.0-rc4-test-00008-g2c6b6b1029d4-dirty #186 Hardware name: QEMU Standard
PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP:
0010:tracing_release_file_tr+0xc/0x50 What happens here is that the kprobe
event creates a trace_event_file “file” descriptor that represents the file
in tracefs to the event. It maintains state of the event (is it enabled for
the given instance?). Opening the “enable” file gets a reference to the
event “file” descriptor via the open file descriptor. When the kprobe event
is deleted, the file is also deleted from the tracefs system which also
frees the event “file” descriptor. But as the tracefs file is still opened
by user space, it will not be totally removed until the final dput() is
called on it. But this is not true with the event “file” descriptor that is
already freed. If the user does a write to or simply closes the file
descriptor it will reference the event “file” descriptor that was just
freed, causing a use-after-free bug. To solve this, add a ref count to the
event “file” descriptor as well as a new flag called “FREED”. The “file”
will not be freed until the last reference is released. But the FREE flag
will be set when the event is removed to prevent any more modifications to
that event from happening, even if there’s still a reference to the event
“file” descriptor.
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
ubuntu | 20.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 23.10 | noarch | linux | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 23.10 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-aws-5.15 | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-aws-6.5 | < any | UNKNOWN |
git.kernel.org/linus/bb32500fb9b78215e4ef6ee8b4345c5f5d7eafb4 (6.7-rc1)
git.kernel.org/stable/c/2c9de867ca285c397cd71af703763fe416265706
git.kernel.org/stable/c/2fa74d29fc1899c237d51bf9a6e132ea5c488976
git.kernel.org/stable/c/9034c87d61be8cff989017740a91701ac8195a1d
git.kernel.org/stable/c/961c4511c7578d6b8f39118be919016ec3db1c1e
git.kernel.org/stable/c/a98172e36e5f1b3d29ad71fade2d611cfcc2fe6f
git.kernel.org/stable/c/bb32500fb9b78215e4ef6ee8b4345c5f5d7eafb4
git.kernel.org/stable/c/cbc7c29dff0fa18162f2a3889d82eeefd67305e0
launchpad.net/bugs/cve/CVE-2023-52879
nvd.nist.gov/vuln/detail/CVE-2023-52879
security-tracker.debian.org/tracker/CVE-2023-52879
www.cve.org/CVERecord?id=CVE-2023-52879