# git rev-parse -q --verify a68a0262abdaa251e12c53715f48e698a18ef402^{commit} a68a0262abdaa251e12c53715f48e698a18ef402 already have revision, skipping fetch # git checkout -q -f -B kisskb a68a0262abdaa251e12c53715f48e698a18ef402 # git clean -qxdf # < git log -1 # commit a68a0262abdaa251e12c53715f48e698a18ef402 # Author: Minchan Kim # Date: Tue Dec 8 20:57:18 2020 -0800 # # mm/madvise: remove racy mm ownership check # # Jann spotted the security hole due to race of mm ownership check. # # If the task is sharing the mm_struct but goes through execve() before # mm_access(), it could skip process_madvise_behavior_valid check. That # makes *any advice hint* to reach into the remote process. # # This patch removes the mm ownership check. With it, it will lose the # ability that local process could give *any* advice hint with vector # interface for some reason (e.g., performance). Since there is no # concrete example in upstream yet, it would be better to remove the # abiliity at this moment and need to review when such new advice comes # up. # # Fixes: ecb8ac8b1f14 ("mm/madvise: introduce process_madvise() syscall: an external memory hinting API") # Reported-by: Jann Horn # Suggested-by: Jann Horn # Signed-off-by: Minchan Kim # Signed-off-by: Linus Torvalds # < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/mips-linux/bin/mips-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/mips-linux/bin/mips-linux-ld --version # < git log --format=%s --max-count=1 a68a0262abdaa251e12c53715f48e698a18ef402 # < make -s -j 8 ARCH=mips O=/kisskb/build/linus_mips-allnoconfig_mips-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/mips-linux/bin/mips-linux- allnoconfig # < make -s -j 8 ARCH=mips O=/kisskb/build/linus_mips-allnoconfig_mips-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/mips-linux/bin/mips-linux- help # make -s -j 8 ARCH=mips O=/kisskb/build/linus_mips-allnoconfig_mips-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/mips-linux/bin/mips-linux- olddefconfig # make -s -j 8 ARCH=mips O=/kisskb/build/linus_mips-allnoconfig_mips-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/mips-linux/bin/mips-linux- FIT description: Linux 5.10.0-rc7+ Created: Wed Dec 9 19:00:31 2020 Image 0 (kernel@0) Description: Linux 5.10.0-rc7+ Created: Wed Dec 9 19:00:31 2020 Type: Kernel Image Compression: gzip compressed Data Size: 676397 Bytes = 660.54 KiB = 0.65 MiB Architecture: MIPS OS: Linux Load Address: 0x80100000 Entry Point: 0x80231124 Hash algo: sha1 Hash value: d0cbe783c752e045a78a73eb61d495d84c37ef95 Default Configuration: 'conf@default' Configuration 0 (conf@default) Description: Generic Linux kernel Kernel: kernel@0 Completed OK # rm -rf /kisskb/build/linus_mips-allnoconfig_mips-gcc8 # Build took: 0:00:29.979736