# 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/hppa-linux/bin/hppa-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/hppa-linux/bin/hppa-linux-ld --version # < git log --format=%s --max-count=1 a68a0262abdaa251e12c53715f48e698a18ef402 # < make -s -j 8 ARCH=parisc O=/kisskb/build/linus_parisc-allnoconfig_parisc-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/hppa-linux/bin/hppa-linux- allnoconfig # < make -s -j 8 ARCH=parisc O=/kisskb/build/linus_parisc-allnoconfig_parisc-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/hppa-linux/bin/hppa-linux- help # make -s -j 8 ARCH=parisc O=/kisskb/build/linus_parisc-allnoconfig_parisc-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/hppa-linux/bin/hppa-linux- olddefconfig # make -s -j 8 ARCH=parisc O=/kisskb/build/linus_parisc-allnoconfig_parisc-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/hppa-linux/bin/hppa-linux- /kisskb/src/arch/parisc/kernel/pci-dma.c:338:12: warning: 'proc_pcxl_dma_show' defined but not used [-Wunused-function] static int proc_pcxl_dma_show(struct seq_file *m, void *v) ^~~~~~~~~~~~~~~~~~ Completed OK # rm -rf /kisskb/build/linus_parisc-allnoconfig_parisc-gcc8 # Build took: 0:00:23.455597