CVE-2022-50282

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

chardev: fix error handling in cdev_device_add()

While doing fault injection test, I got the following report:

————[ cut here ]———— kobject: (null) (0000000039956980): is not initialized, yet kobject_put() is being called. WARNING: CPU: 3 PID: 6306 at kobject_put+0x23d/0x4e0 CPU: 3 PID: 6306 Comm: 283 Tainted: G W 6.1.0-rc2-00005-g307c1086d7c9 #1253 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:kobject_put+0x23d/0x4e0 Call Trace: cdev_device_add+0x15e/0x1b0 __iio_device_register+0x13b4/0x1af0 [industrialio] __devm_iio_device_register+0x22/0x90 [industrialio] max517_probe+0x3d8/0x6b4 [max517] i2c_device_probe+0xa81/0xc00

When device_add() is injected fault and returns error, if dev->devt is not set, cdev_add() is not called, cdev_del() is not needed. Fix this by checking dev->devt in error path.

Affected Software

References

• https://git.kernel.org/stable/c/11fa7fefe3d8fac7da56bc9aa3dd5fb3081ca797
• https://git.kernel.org/stable/c/28dc61cc49c6e995121c6d86bef4b73df78dda80
• https://git.kernel.org/stable/c/34d17b39bceef25e4cf9805cd59250ae05d0a139
• https://git.kernel.org/stable/c/5d2146889fad4cb9e6c13e790d4cfd871486eca8
• https://git.kernel.org/stable/c/6acf8597c5b04f455ee0649e11e5f3bcd28f381e
• https://git.kernel.org/stable/c/85a5660491b507d33662b8e81c142e6041e642eb
• https://git.kernel.org/stable/c/b5de1eac71fec1af7723f1083d23a24789fd795c
• https://git.kernel.org/stable/c/c46db6088bccff5115674d583fef46ede80077a2
• https://git.kernel.org/stable/c/d85b5247a79355b8432bfd9ac871f96117f750d4