The patch titled
NOMMU: Permit ptrace to ignore non-PROT_WRITE VMAs in NOMMU mode
has been removed from the -mm tree. Its filename is
nommu-permit-ptrace-to-ignore-non-prot_write-vmas-in-nommu-mode.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
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
@@ -1258,9 +1258,9 @@ 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
origin.patch
git-block.patch
git-block-hack.patch
git-gfs2.patch
git-serial.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
kill-wall_jiffies.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-kconfig-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
nfs-use-local-caching-kconfig-fix.patch
add-missing-page_copy-export-for-ppc-and-powerpc.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
afs-amend-the-afs-configuration-options.patch
generic-ioremap_page_range-implementation-nommu-fix.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
ecryptfs-inode-numbering-fixes.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
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