The Linux kernel through 5.0.7, when CONFIG_IA32_AOUT is enabled and...

Vulnerability Description

The Linux kernel through 5.0.7, when CONFIG_IA32_AOUT is enabled and ia32_aout is loaded, allows local users to bypass ASLR on setuid a.out programs (if any exist) because install_exec_creds() is called too late in load_aout_binary() in fs/binfmt_aout.c, and thus the ptrace_may_access() check has a race condition when reading /proc/pid/stat. NOTE: the software maintainer disputes that this is a vulnerability because ASLR for a.out format executables has never been supported

References

• https://www.openwall.com/lists/oss-security/2019/04/03/4
• https://www.openwall.com/lists/oss-security/2019/04/03/4/1
• http://www.securityfocus.com/bid/107887
• http://www.openwall.com/lists/oss-security/2019/04/18/5
• http://www.openwall.com/lists/oss-security/2019/05/22/7
• https://usn.ubuntu.com/4007-2/
• https://usn.ubuntu.com/4008-1/
• https://usn.ubuntu.com/4006-1/
• https://usn.ubuntu.com/4006-2/
• https://usn.ubuntu.com/4007-1/
• https://usn.ubuntu.com/4008-3/
• http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00039.html