CVE-2021-46905

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

net: hso: fix NULL-deref on disconnect regression

Commit 8a12f8836145 (net: hso: fix null-ptr-deref during tty device unregistration) fixed the racy minor allocation reported by syzbot, but introduced an unconditional NULL-pointer dereference on every disconnect instead.

Specifically, the serial device table must no longer be accessed after the minor has been released by hso_serial_tty_unregister().

Weakness

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/0c71d4c89559f72cec2592d078681a843bce570e
• https://git.kernel.org/stable/c/0f000005da31f6947f843ce6b3e3a960540c6e00
• https://git.kernel.org/stable/c/24b699bea7553fc0b98dad9d864befb6005ac7f1
• https://git.kernel.org/stable/c/2ad5692db72874f02b9ad551d26345437ea4f7f3
• https://git.kernel.org/stable/c/41c44e1f3112d7265dae522c026399b2a42d19ef
• https://git.kernel.org/stable/c/5871761c5f0f20d6e98bf3b6bd7486d857589554
• https://git.kernel.org/stable/c/5c17cfe155d21954b4c7e2a78fa771cebcd86725
• https://git.kernel.org/stable/c/90642ee9eb581a13569b1c0bd57e85d962215273
• https://git.kernel.org/stable/c/d7fad2ce15bdbbd0fec3ebe999fd7cab2267f53e