CVE-2022-49339

Summary

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

net: ipv6: unexport __init-annotated seg6_hmac_init()

EXPORT_SYMBOL and __init is a bad combination because the .init.text section is freed up after the initialization. Hence, modules cannot use symbols annotated __init. The access to a freed symbol may end up with kernel panic.

modpost used to detect it, but it has been broken for a decade.

Recently, I fixed modpost so it started to warn it again, then this showed up in linux-next builds.

There are two ways to fix it:

  • Remove __init
  • Remove EXPORT_SYMBOL

I chose the latter for this case because the caller (net/ipv6/seg6.c) and the callee (net/ipv6/seg6_hmac.c) belong to the same module. It seems an internal function call in ipv6.ko.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxbf355b8d2c30a289232042cacc1cfaea4923936c < 64aef8efe96c1616142c4476a05731306fc4494eaffected
LinuxLinuxbf355b8d2c30a289232042cacc1cfaea4923936c < ab8b2c2de273ec1d698a18e399896a6febb5cda0affected
LinuxLinuxbf355b8d2c30a289232042cacc1cfaea4923936c < 317260b3eb6384a05a8af212308fa50f3b2e8290affected
LinuxLinuxbf355b8d2c30a289232042cacc1cfaea4923936c < 5d9c1b081ad28c852a97e10dd75412546497694aaffected
LinuxLinuxbf355b8d2c30a289232042cacc1cfaea4923936c < 1084716f76c8045eadf92a9d9a62641f3c8d8c90affected
LinuxLinuxbf355b8d2c30a289232042cacc1cfaea4923936c < 3e6de5037148c5a93a436b1e8d2edad3dac11755affected
LinuxLinuxbf355b8d2c30a289232042cacc1cfaea4923936c < 9ba4416b831eeb4d185e88e73488d1d21288e63aaffected
LinuxLinuxbf355b8d2c30a289232042cacc1cfaea4923936c < 5801f064e35181c71857a80ff18af4dbec3c5f5caffected
LinuxLinux4.10affected
LinuxLinux0 < 4.10unaffected
LinuxLinux4.14.283 <= 4.14.*unaffected
LinuxLinux4.19.247 <= 4.19.*unaffected
LinuxLinux5.4.198 <= 5.4.*unaffected
LinuxLinux5.10.122 <= 5.10.*unaffected
LinuxLinux5.15.47 <= 5.15.*unaffected
LinuxLinux5.17.15 <= 5.17.*unaffected
LinuxLinux5.18.4 <= 5.18.*unaffected
LinuxLinux5.19 <= *unaffected

Weaknesses

References