The patch titled
NOMMU: Permit ptrace to ignore non-PROT_WRITE VMAs in NOMMU mode
has been added to the -mm tree. Its filename is
nommu-permit-ptrace-to-ignore-non-prot_write-vmas-in-nommu-mode.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: NOMMU: Permit ptrace to ignore non-PROT_WRITE VMAs in NOMMU mode
From: David Howells <dhowells@xxxxxxxxxx>
Permit ptrace to modify a section that's non-shared but is marked
unwritable, such as is obtained by mapping the text segment of an ELF-FDPIC
executable binary with into a binary that's being ptraced[*].
[*] Under NOMMU conditions ptrace causes read-only MAP_PRIVATE mmaps to become
totally private copies because if a private mapping was actually shared
then the debugging setting breakpoints in it would potentially crash
other processes.
This is done by using the VM_MAYWRITE flag rather than the VM_WRITE flag
when deciding whether to permit a write.
Without this patch a debugger can't set breakpoints in the mapped text
sections of executables that are mapped read-only private, even if the
mmap() syscall has taken a private copy because PT_PTRACED is set.
In addition, VM_MAYREAD is used instead of VM_READ for similar reasons.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
mm/nommu.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN mm/nommu.c~nommu-permit-ptrace-to-ignore-non-prot_write-vmas-in-nommu-mode mm/nommu.c
--- a/mm/nommu.c~nommu-permit-ptrace-to-ignore-non-prot_write-vmas-in-nommu-mode
+++ a/mm/nommu.c
@@ -1238,9 +1238,9 @@ int access_process_vm(struct task_struct
len = vma->vm_end - addr;
/* only read or write mappings where it is permitted */
- if (write && vma->vm_flags & VM_WRITE)
+ if (write && vma->vm_flags & VM_MAYWRITE)
len -= copy_to_user((void *) addr, buf, len);
- else if (!write && vma->vm_flags & VM_READ)
+ else if (!write && vma->vm_flags & VM_MAYREAD)
len -= copy_from_user(buf, (void *) addr, len);
else
len = 0;
_
Patches currently in -mm which might be from dhowells@xxxxxxxxxx are
git-block.patch
git-gfs2.patch
git-nfs.patch
nfs-replace-null-dentries-that-appear-in-readdirs-list-2.patch
binfmt_elf-consistently-use-loff_t.patch
nommu-check-that-access_process_vm-has-a-valid-target.patch
nommu-set-bdi-capabilities-for-dev-mem-and-dev-kmem.patch
nommu-set-bdi-capabilities-for-dev-mem-and-dev-kmem-tidy.patch
nommu-use-find_vma-rather-than-reimplementing-a-vma-search.patch
check-if-start-address-is-in-vma-region-in-nommu-function-get_user_pages.patch
nommu-permit-ptrace-to-ignore-non-prot_write-vmas-in-nommu-mode.patch
afs-add-lock-annotations-to-afs_proc_cell_servers_startstop.patch
elf_fdpic_core_dump-dont-take-tasklist_lock.patch
simplify-update_times-avoid-jiffies-jiffies_64-aliasing-problem-2.patch
lib-rwsemc-un-inline-rwsem_down_failed_common.patch
reiserfs-make-sure-all-dentries-refs-are-released-before-calling-kill_block_super-try-2.patch
fs-cache-provide-a-filesystem-specific-syncable-page-bit.patch
fs-cache-generic-filesystem-caching-facility.patch
fs-cache-release-page-private-in-failed-readahead.patch
fs-cache-release-page-private-after-failed-readahead-12.patch
fs-cache-make-kafs-use-fs-cache.patch
fs-cache-make-kafs-use-fs-cache-fix.patch
fs-cache-make-kafs-use-fs-cache-12.patch
fs-cache-make-kafs-use-fs-cache-12-fix.patch
fs-cache-make-kafs-use-fs-cache-vs-streamline-generic_file_-interfaces-and-filemap.patch
nfs-use-local-caching.patch
nfs-use-local-caching-12.patch
nfs-use-local-caching-12-fix.patch
fs-cache-cachefiles-ia64-missing-copy_page-export.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem-cachefiles-printk-format-warning.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem-warning-fixes.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem-cachefiles-cachefiles_write_page-shouldnt-indicate-error-twice.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem-cachefiles-handle-enospc-on-create-mkdir-better.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem-inode-count-maintenance.patch
autofs-make-sure-all-dentries-refs-are-released-before-calling-kill_anon_super.patch
vfs-destroy-the-dentries-contributed-by-a-superblock-on-unmounting.patch
vfs-make-filldir_t-and-struct-kstat-deal-in-64-bit-inode-numbers.patch
vfs-make-filldir_t-and-struct-kstat-deal-in-64-bit-inode-numbers-alpha-fix.patch
nfs-represent-64-bit-fileids-as-64-bit-inode-numbers-on-32-bit-systems.patch
ecryptfs-get_sb_dev-fix.patch
introduce-kernel_execve.patch
rename-the-provided-execve-functions-to-kernel_execve.patch
provide-kernel_execve-on-all-architectures.patch
provide-kernel_execve-on-all-architectures-fix.patch
remove-the-use-of-_syscallx-macros-in-uml.patch
sh64-remove-the-use-of-kernel-syscalls.patch
remove-remaining-errno-and-__kernel_syscalls__-references.patch
reiser4-get_sb_dev-fix.patch
mutex-subsystem-synchro-test-module.patch
-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
