# 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-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version # < git log --format=%s --max-count=1 a68a0262abdaa251e12c53715f48e698a18ef402 # < make -s -j 8 ARCH=powerpc O=/kisskb/build/linus_44x_fsp2_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- 44x/fsp2_defconfig # < make -s -j 8 ARCH=powerpc O=/kisskb/build/linus_44x_fsp2_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- help # make -s -j 8 ARCH=powerpc O=/kisskb/build/linus_44x_fsp2_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- olddefconfig # make -s -j 8 ARCH=powerpc O=/kisskb/build/linus_44x_fsp2_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- In file included from /kisskb/src/kernel/rcu/update.c:578:0: /kisskb/src/kernel/rcu/tasks.h:710:13: warning: 'show_rcu_tasks_rude_gp_kthread' defined but not used [-Wunused-function] static void show_rcu_tasks_rude_gp_kthread(void) {} ^ INFO: Uncompressed kernel (size 0xa76e94) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xb00000) Image Name: Linux-5.10.0-rc7-67294-ga68a0262 Created: Wed Dec 9 18:28:19 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 4561532 Bytes = 4454.62 KiB = 4.35 MiB Load Address: 00000000 Entry Point: 00000000 Completed OK # rm -rf /kisskb/build/linus_44x_fsp2_defconfig_powerpc-gcc5 # Build took: 0:01:51.427186