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>
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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
00-INDEX
00-INDEX
- This file
apm-acpi.txt
- basic info about the APM and ACPI support.
basic-pm-debugging.txt
- Debugging suspend and resume
devices.txt
- How drivers interact with system-wide power management
drivers-testing.txt
- Testing suspend and resume support in device drivers
freezing-of-tasks.txt
- How processes and controlled during suspend
interface.txt
- Power management user interface in /sys/power
notifiers.txt
- Registering suspend notifiers in device drivers
opp.txt
- Operating Performance Point library
pci.txt
- How the PCI Subsystem Does Power Management
pm_qos_interface.txt
- info on Linux PM Quality of Service interface
power_supply_class.txt
- Tells userspace about battery, UPS, AC or DC power supply properties
s2ram.txt
- How to get suspend to ram working (and debug it when it isn't)
states.txt
- System power management states
swsusp-and-swap-files.txt
- Using swap files with software suspend (to disk)
swsusp-dmcrypt.txt
- How to use dm-crypt and software suspend (to disk) together
swsusp.txt
- Goals, implementation, and usage of software suspend (ACPI S3)
tricks.txt
- How to trick software suspend (to disk) into working when it isn't
userland-swsusp.txt
- Experimental implementation of software suspend in userspace
video_extension.txt
- ACPI video extensions
video.txt
- Video issues during resume from suspend
Computing file changes ...