Vulnerability CVE-2024-39496
Published: 2024-07-12

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

btrfs: zoned: fix use-after-free due to race with dev replace

While loading a zone's info during creation of a block group, we can race
with a device replace operation and then trigger a use-after-free on the
device that was just replaced (source device of the replace operation).

This happens because at btrfs_load_zone_info() we extract a device from
the chunk map into a local variable and then use the device while not
under the protection of the device replace rwsem. So if there's a device
replace operation happening when we extract the device and that device
is the source of the replace operation, we will trigger a use-after-free
if before we finish using the device the replace operation finishes and
frees the device.

Fix this by enlarging the critical section under the protection of the
device replace rwsem so that all uses of the device are done inside the
critical section.

 References:
https://git.kernel.org/stable/c/17765964703b88d8befd899f8501150bb7e07e43
https://git.kernel.org/stable/c/092571ef9a812566c8f2c9038d9c2a64c49788d6
https://git.kernel.org/stable/c/a0cc006f4214b87e70983c692e05bb36c59b5752
https://git.kernel.org/stable/c/0090d6e1b210551e63cf43958dc7a1ec942cdde9
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