The do_shmat function in ipc/shm.c in the Linux kernel, through 4.9.12, does not restrict the address calculated by a certain rounding operation. This allows privileged local users to map page zero and, consequently, bypass a protection mechanism that exists for the mmap system call. This is possible by making crafted shmget and shmat system calls in a privileged context.
Find out more about CVE-2017-5669 from the MITRE CVE dictionary dictionary and NIST NVD.
This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5, 6, 7 and Red Hat Enterprise MRG-2 as the flaw can only be exploited by a privileged user.
NOTE: The following CVSS v3 metrics and score provided are preliminary and subject to review.
| CVSS3 Base Score | 6.7 |
|---|---|
| CVSS3 Base Metrics | CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |
| Attack Vector | Local |
| Attack Complexity | Low |
| Privileges Required | High |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality | High |
| Integrity Impact | High |
| Availability Impact | High |
| Platform | Package | State |
|---|---|---|
| Red Hat Enterprise MRG 2 | realtime-kernel | Will not fix |
| Red Hat Enterprise Linux 7 | kernel-rt | Will not fix |
| Red Hat Enterprise Linux 7 | kernel | Will not fix |
| Red Hat Enterprise Linux 6 | kernel | Will not fix |
| Red Hat Enterprise Linux 5 | kernel | Will not fix |
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