CVE-2017-5856

Memory leak in the megasas_handle_dcmd function in hw/scsi/megasas.c in QEMU (aka Quick Emulator) allows local guest OS privileged users to cause a denial of service (host memory consumption) via MegaRAID Firmware Interface (MFI) commands with the sglist size set to a value over 2 Gb.

Weakness

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Affected Software

Potential Mitigations

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References

• http://git.qemu-project.org/?p=qemu.git%3Ba=commit%3Bh=765a707000e838c30b18d712fe6cb3dd8e0435f3
• http://www.openwall.com/lists/oss-security/2017/02/01/19
• http://www.openwall.com/lists/oss-security/2017/02/02/14
• http://www.securityfocus.com/bid/95999
• https://bugzilla.redhat.com/show_bug.cgi?id=1418342
• https://lists.debian.org/debian-lts-announce/2018/09/msg00007.html
• https://security.gentoo.org/glsa/201702-28
• http://git.qemu-project.org/?p=qemu.git%3Ba=commit%3Bh=765a707000e838c30b18d712fe6cb3dd8e0435f3
• http://www.openwall.com/lists/oss-security/2017/02/01/19
• http://www.openwall.com/lists/oss-security/2017/02/02/14
• http://www.securityfocus.com/bid/95999
• https://bugzilla.redhat.com/show_bug.cgi?id=1418342
• https://lists.debian.org/debian-lts-announce/2018/09/msg00007.html
• https://security.gentoo.org/glsa/201702-28