https://github.com/torvalds/linux
Revision 462e635e5b73ba9a4c03913b77138cd57ce4b050 authored by Tavis Ormandy on 09 December 2010, 14:29:42 UTC, committed by Linus Torvalds on 15 December 2010, 20:30:36 UTC
The install_special_mapping routine (used, for example, to setup the vdso) skips the security check before insert_vm_struct, allowing a local attacker to bypass the mmap_min_addr security restriction by limiting the available pages for special mappings. bprm_mm_init() also skips the check, and although I don't think this can be used to bypass any restrictions, I don't see any reason not to have the security check. $ uname -m x86_64 $ cat /proc/sys/vm/mmap_min_addr 65536 $ cat install_special_mapping.s section .bss resb BSS_SIZE section .text global _start _start: mov eax, __NR_pause int 0x80 $ nasm -D__NR_pause=29 -DBSS_SIZE=0xfffed000 -f elf -o install_special_mapping.o install_special_mapping.s $ ld -m elf_i386 -Ttext=0x10000 -Tbss=0x11000 -o install_special_mapping install_special_mapping.o $ ./install_special_mapping & [1] 14303 $ cat /proc/14303/maps 0000f000-00010000 r-xp 00000000 00:00 0 [vdso] 00010000-00011000 r-xp 00001000 00:19 2453665 /home/taviso/install_special_mapping 00011000-ffffe000 rwxp 00000000 00:00 0 [stack] It's worth noting that Red Hat are shipping with mmap_min_addr set to 4096. Signed-off-by: Tavis Ormandy <taviso@google.com> Acked-by: Kees Cook <kees@ubuntu.com> Acked-by: Robert Swiecki <swiecki@google.com> [ Changed to not drop the error code - akpm ] Reviewed-by: James Morris <jmorris@namei.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 0fcdcfb
Tip revision: 462e635e5b73ba9a4c03913b77138cd57ce4b050 authored by Tavis Ormandy on 09 December 2010, 14:29:42 UTC
install_special_mapping skips security_file_mmap check.
install_special_mapping skips security_file_mmap check.
Tip revision: 462e635
File | Mode | Size |
---|---|---|
debugfs-ec | -rw-r--r-- | 838 bytes |
debugfs-pktcdvd | -rw-r--r-- | 448 bytes |
ima_policy | -rw-r--r-- | 1.9 KB |
procfs-diskstats | -rw-r--r-- | 655 bytes |
sysfs-ata | -rw-r--r-- | 2.4 KB |
sysfs-block | -rw-r--r-- | 5.2 KB |
sysfs-block-zram | -rw-r--r-- | 3.3 KB |
sysfs-bus-css | -rw-r--r-- | 1.4 KB |
sysfs-bus-i2c-devices-hm6352 | -rw-r--r-- | 640 bytes |
sysfs-bus-pci | -rw-r--r-- | 6.4 KB |
sysfs-bus-pci-devices-cciss | -rw-r--r-- | 1.9 KB |
sysfs-bus-rbd | -rw-r--r-- | 1.7 KB |
sysfs-bus-umc | -rw-r--r-- | 1018 bytes |
sysfs-bus-usb | -rw-r--r-- | 5.0 KB |
sysfs-bus-usb-devices-usbsevseg | -rw-r--r-- | 1.5 KB |
sysfs-c2port | -rw-r--r-- | 2.9 KB |
sysfs-class | -rw-r--r-- | 520 bytes |
sysfs-class-bdi | -rw-r--r-- | 1.5 KB |
sysfs-class-lcd | -rw-r--r-- | 681 bytes |
sysfs-class-led | -rw-r--r-- | 966 bytes |
sysfs-class-mtd | -rw-r--r-- | 3.7 KB |
sysfs-class-pktcdvd | -rw-r--r-- | 2.7 KB |
sysfs-class-power | -rw-r--r-- | 756 bytes |
sysfs-class-regulator | -rw-r--r-- | 11.4 KB |
sysfs-class-uwb_rc | -rw-r--r-- | 5.1 KB |
sysfs-class-uwb_rc-wusbhc | -rw-r--r-- | 1.6 KB |
sysfs-dev | -rw-r--r-- | 693 bytes |
sysfs-devices | -rw-r--r-- | 1021 bytes |
sysfs-devices-memory | -rw-r--r-- | 3.3 KB |
sysfs-devices-node | -rw-r--r-- | 299 bytes |
sysfs-devices-platform-_UDC_-gadget | -rw-r--r-- | 667 bytes |
sysfs-devices-power | -rw-r--r-- | 6.8 KB |
sysfs-devices-system-cpu | -rw-r--r-- | 6.9 KB |
sysfs-devices-system-ibm-rtl | -rw-r--r-- | 817 bytes |
sysfs-driver-hid-picolcd | -rw-r--r-- | 1.8 KB |
sysfs-driver-hid-prodikeys | -rw-r--r-- | 985 bytes |
sysfs-driver-hid-roccat-kone | -rw-r--r-- | 4.1 KB |
sysfs-driver-hid-roccat-pyra | -rw-r--r-- | 4.4 KB |
sysfs-firmware-acpi | -rw-r--r-- | 4.2 KB |
sysfs-firmware-memmap | -rw-r--r-- | 2.3 KB |
sysfs-firmware-sfi | -rw-r--r-- | 466 bytes |
sysfs-firmware-sgi_uv | -rw-r--r-- | 889 bytes |
sysfs-fs-ext4 | -rw-r--r-- | 3.0 KB |
sysfs-gpio | -rw-r--r-- | 1.1 KB |
sysfs-i2c-bmp085 | -rw-r--r-- | 1.1 KB |
sysfs-ibft | -rw-r--r-- | 1022 bytes |
sysfs-kernel-mm | -rw-r--r-- | 202 bytes |
sysfs-kernel-mm-hugepages | -rw-r--r-- | 521 bytes |
sysfs-kernel-slab | -rw-r--r-- | 16.9 KB |
sysfs-kernel-uids | -rw-r--r-- | 658 bytes |
sysfs-memory-page-offline | -rw-r--r-- | 1.6 KB |
sysfs-module | -rw-r--r-- | 337 bytes |
sysfs-ocfs2 | -rw-r--r-- | 3.0 KB |
sysfs-platform-asus-laptop | -rw-r--r-- | 2.0 KB |
sysfs-platform-eeepc-laptop | -rw-r--r-- | 1.5 KB |
sysfs-platform-eeepc-wmi | -rw-r--r-- | 344 bytes |
sysfs-power | -rw-r--r-- | 6.7 KB |
sysfs-pps | -rw-r--r-- | 2.1 KB |
sysfs-profiling | -rw-r--r-- | 331 bytes |
sysfs-wacom | -rw-r--r-- | 404 bytes |
sysfs-wusb_cbaf | -rw-r--r-- | 3.9 KB |
Computing file changes ...