CVE-2021-47276

Summary

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

ftrace: Do not blindly read the ip address in ftrace_bug()

It was reported that a bug on arm64 caused a bad ip address to be used for updating into a nop in ftrace_init(), but the error path (rightfully) returned -EINVAL and not -EFAULT, as the bug caused more than one error to occur. But because -EINVAL was returned, the ftrace_bug() tried to report what was at the location of the ip address, and read it directly. This caused the machine to panic, as the ip was not pointing to a valid memory address.

Instead, read the ip address with copy_from_kernel_nofault() to safely access the memory, and if it faults, report that the address faulted, otherwise report what was in that location.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux05736a427f7e16be948ccbf39782bd3a6ae16b14 < 0bc62e398bbd9e600959e610def5109957437b28affected
LinuxLinux05736a427f7e16be948ccbf39782bd3a6ae16b14 < 4aedc2bc2b32c93555f47c95610efb89cc1ec09baffected
LinuxLinux05736a427f7e16be948ccbf39782bd3a6ae16b14 < acf671ba79c1feccc3ec7cfdcffead4efcec49e7affected
LinuxLinux05736a427f7e16be948ccbf39782bd3a6ae16b14 < 862dcc14f2803c556bdd73b43c27b023fafce2fbaffected
LinuxLinux05736a427f7e16be948ccbf39782bd3a6ae16b14 < 7e4e824b109f1d41ccf223fbb0565d877d6223a2affected
LinuxLinux05736a427f7e16be948ccbf39782bd3a6ae16b14 < 97524384762c1fb9b3ded931498dd2047bd0de81affected
LinuxLinux05736a427f7e16be948ccbf39782bd3a6ae16b14 < 3e4ddeb68751fb4fb657199aed9cfd5d02796875affected
LinuxLinux05736a427f7e16be948ccbf39782bd3a6ae16b14 < 6c14133d2d3f768e0a35128faac8aa6ed4815051affected
LinuxLinux2.6.28affected
LinuxLinux0 < 2.6.28unaffected
LinuxLinux4.4.273 <= 4.4.*unaffected
LinuxLinux4.9.273 <= 4.9.*unaffected
LinuxLinux4.14.237 <= 4.14.*unaffected
LinuxLinux4.19.195 <= 4.19.*unaffected
LinuxLinux5.4.126 <= 5.4.*unaffected
LinuxLinux5.10.44 <= 5.10.*unaffected
LinuxLinux5.12.11 <= 5.12.*unaffected
LinuxLinux5.13 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

References