https://github.com/torvalds/linux
Revision fe936dfc23fed3475b11067e8d9b70553eafcd9e authored by Michael Ellerman on 14 April 2011, 22:22:10 UTC, committed by Linus Torvalds on 14 April 2011, 23:06:55 UTC
In __access_remote_vm() we need to check that we have found the right vma, not the following vma before we try to access it. Otherwise we might call the vma's access routine with an address which does not fall inside the vma. It was discovered on a current kernel but with an unreleased driver, from memory it was strace leading to a kernel bad access, but it obviously depends on what the access implementation does. Looking at other access implementations I only see: $ git grep -A 5 vm_operations|grep access arch/powerpc/platforms/cell/spufs/file.c- .access = spufs_mem_mmap_access, arch/x86/pci/i386.c- .access = generic_access_phys, drivers/char/mem.c- .access = generic_access_phys fs/sysfs/bin.c- .access = bin_access, The spufs one looks like it might behave badly given the wrong vma, it assumes vma->vm_file->private_data is a spu_context, and looks like it would probably blow up pretty quickly if it wasn't. generic_access_phys() only uses the vma to check vm_flags and get the mm, and then walks page tables using the address. So it should bail on the vm_flags check, or at worst let you access some other VM_IO mapping. And bin_access() just proxies to another access implementation. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 4471a67
Tip revision: fe936dfc23fed3475b11067e8d9b70553eafcd9e authored by Michael Ellerman on 14 April 2011, 22:22:10 UTC
mm: check that we have the right vma in __access_remote_vm()
mm: check that we have the right vma in __access_remote_vm()
Tip revision: fe936df
File | Mode | Size |
---|---|---|
Documentation | ||
arch | ||
block | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.gitignore | -rw-r--r-- | 941 bytes |
.mailmap | -rw-r--r-- | 4.1 KB |
COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 91.7 KB |
Kbuild | -rw-r--r-- | 2.4 KB |
Kconfig | -rw-r--r-- | 252 bytes |
MAINTAINERS | -rw-r--r-- | 188.3 KB |
Makefile | -rw-r--r-- | 51.1 KB |
README | -rw-r--r-- | 17.1 KB |
REPORTING-BUGS | -rw-r--r-- | 3.3 KB |
Computing file changes ...