Out-of-Bounds Affecting kernel-kdump-devel package, versions <0:3.10.0-693.el7

Note: Versions mentioned in the description apply only to the upstream kernel-kdump-devel package and not the kernel-kdump-devel package as distributed by RHEL. See How to fix? for RHEL:7 relevant fixed versions and status.

Linux distributions that have not patched their long-term kernels with https://git.kernel.org/linus/a87938b2e246b81b4fb713edb371a9fa3c5c3c86 (committed on April 14, 2015). This kernel vulnerability was fixed in April 2015 by commit a87938b2e246b81b4fb713edb371a9fa3c5c3c86 (backported to Linux 3.10.77 in May 2015), but it was not recognized as a security threat. With CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE enabled, and a normal top-down address allocation strategy, load_elf_binary() will attempt to map a PIE binary into an address range immediately below mm->mmap_base. Unfortunately, load_elf_ binary() does not take account of the need to allocate sufficient space for the entire binary which means that, while the first PT_LOAD segment is mapped below mm->mmap_base, the subsequent PT_LOAD segment(s) end up being mapped above mm->mmap_base into the are that is supposed to be the "gap" between the stack and the binary.

• http://www.securityfocus.com/bid/101010
• https://access.redhat.com/security/cve/CVE-2017-1000253
• https://www.qualys.com/2017/09/26/cve-2017-1000253/cve-2017-1000253.txt
• https://access.redhat.com/errata/RHSA-2017:1842
• http://www.securitytracker.com/id/1039434
• https://www.exploit-db.com/exploits/42887
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog