This commits adds a basic infrastructure to support Address Space
Randomization (ASR). In a nutshell, using the already imported ASR
LLVM pass, multiple versions can be generated for the same system
service, each with a randomized, different address space layout.
Combined with the magic instrumentation for state transfer, a system
service can be live updated into another ASR-randomized version at
runtime, thus providing live rerandomization.
Since MINIX3 is not yet capable of running LLVM linker passes, the
ASR-randomized service binaries have to be pregenerated during
crosscompilation. These pregenerated binaries can then be cycled
through at runtime. This patch provides the basic proof-of-concept
infrastructure for both these parts.
In order to support pregeneration, the clientctl host script has
been extended with a "buildasr" command. It is to be used after
building the entire system with bitcode and magic support, and will
produce a given number of ASR-randomized versions of all system
services. These services are placed in /usr/service/asr in the
image that is generated as final step by the "buildasr" command.
In order to support runtime updating, a new update_asr(8) command
has been added to MINIX3. This command attempts to live-update the
running system services into their next ASR-randomized versions.
For now, this command is not run automatically, and thus must be
invoked manually.
Technical notes:
- For various reasons, magic instrumentation is x86-only for now,
and ASR functionality is therefore to be used on x86 only as well.
- The ASR-randomized binaries are placed in numbered subdirectories
so as not to have to change their actual program names, which are
assumed to be static in various places (system.conf, procfs).
- The root partition is typically too small to contain all the
produced binaries, which is why we introduce /usr/service. There
is a symlink from /service/asr to /usr/service/asr for no other
reason than to let userland continue to assume that all services
are reachable through /service.
- The ASR count field (r_asr_count/ASRcount) maintained by RS is not
used within RS in any way; it is only passed through procfs to
userland in order to allow update_asr(8) to keep track of which
version is currently loaded without having to maintain own state.
- Ideally, pre-instrumentation linking of a service would remove all
its randomized versions. Currently, the user is assumed not to
perform ASR instrumentation and then recompile system services
without performing ASR instrumentation again, as the randomized
binaries included in the image would then be stale. This aspect
has to be improved later.
- Various other issues are flagged in the comments of the various
parts of this patch.
Change-Id: I093ad57f31c18305591f64b2d491272288aa0937
Due to changed VM internals, more elaborate preparation is required
before a live update with multiple components including VM can take
place. This patch adds the essential preparation infrastructure to
VM and adapts RS to make use of it. As a side effect, it is no
longer necessary to supply RS as the last component (if at all)
during the set-up of a multicomponent live update operation.
Change-Id: If069fd3f93f96f9d5433998e4615f861465ef448
This patch employs one solution to resolve two independent but related
issues. Both issues are the result of one fundamental aspect of the
way VM's memory mapping works: VM uses its cache to map in blocks for
memory-mapped file regions, and for blocks already in the VM cache, VM
does not go to the file system before mapping them in. To preserve
consistency between the FS and VM caches, VM relies on being informed
about all updates to file contents through the block cache. The two
issues are both the result of VM not being properly informed about
such updates:
1. Once a file system provides libminixfs with an inode association
(inode number + inode offset) for a disk block, this association
is not broken until a new inode association is provided for it.
If a block is freed and reallocated as a metadata (non-inode)
block, its old association is maintained, and may be supplied to
VM's secondary cache. Due to reuse of inodes, it is possible
that the same inode association becomes valid for an actual file
block again. In that case, when that new file is memory-mapped,
under certain circumstances, VM may end up using the metadata
block to satisfy a page fault on the file, due to the stale inode
association. The result is a corrupted memory mapping, with the
application seeing data other than the current file contents
mapped in at the file block.
2. When a hole is created in a file, the underlying block is freed
from the device, but VM is not informed of this update, and thus,
if VM's cache contains the block with its previous inode
association, this block will remain there. As a result, if an
application subsequently memory-maps the file, VM will map in the
old block at the position of the hole, rather than an all-zeroes
block. Thus, again, the result is a corrupted memory mapping.
This patch resolves both issues by making the file system inform the
minixfs library about blocks being freed, so that libminixfs can
break the inode association for that block, both in its own cache and
in the VM cache. Since libminixfs does not know whether VM has the
block in its cache or not, it makes a call to VM for each block being
freed. Thus, this change introduces more calls to VM, but it solves
the correctness issues at hand; optimizations may be introduced
later. On the upside, all freed blocks are now marked as clean,
which should result in fewer blocks being written back to the device,
and the blocks are removed from the caches entirely, which should
result in slightly better cache usage.
This patch is necessary but not sufficient to resolve the situation
with respect to memory mapping of file holes in general. Therefore,
this patch extends test 74 with a (rather particular but effective)
test for the first issue, but not yet with a test for the second one.
This fixes#90.
Change-Id: Iad8b134d2f88a884f15d3fc303e463280749c467
The primary reason for the import is a likely GPL taint of the
original MINIX3 syslogd. As a result, this import may still
have some rough edges.
Change-Id: I5c8d26eca10fc2dd50ecc9eab44a1d483cf068a9
This patch adds support for Unix98 pseudo terminals, that is,
posix_openpt(3), grantpt(3), unlockpt(3), /dev/ptmx, and /dev/pts/.
The latter is implemented with a new pseudo file system, PTYFS.
In effect, this patch adds secure support for unprivileged pseudo
terminal allocation, allowing programs such as tmux(1) to be used by
non-root users as well. Test77 has been extended with new tests, and
no longer needs to run as root.
The new functionality is optional. To revert to the old behavior,
remove the "ptyfs" entry from /etc/fstab.
Technical nodes:
o The reason for not implementing the NetBSD /dev/ptm approach is that
implementing the corresponding ioctl (TIOCPTMGET) would require
adding a number of extremely hairy exceptions to VFS, including the
PTY driver having to create new file descriptors for its own device
nodes.
o PTYFS is required for Unix98 PTYs in order to avoid that the PTY
driver has to be aware of old-style PTY naming schemes and even has
to call chmod(2) on a disk-backed file system. PTY cannot be its
own PTYFS since a character driver may currently not also be a file
system. However, PTYFS may be subsumed into a DEVFS in the future.
o The Unix98 PTY behavior differs somewhat from NetBSD's, in that
slave nodes are created on ptyfs only upon the first call to
grantpt(3). This approach obviates the need to revoke access as
part of the grantpt(3) call.
o Shutting down PTY may leave slave nodes on PTYFS, but once PTY is
restarted, these leftover slave nodes will be removed before they
create a security risk. Unmounting PTYFS will make existing PTY
slaves permanently unavailable, and absence of PTYFS will block
allocation of new Unix98 PTYs until PTYFS is (re)mounted.
Change-Id: I822b43ba32707c8815fd0f7d5bb7a438f51421c1
As suggested in issue #43.
Historic Locations:
Prior to this commit
minix/commands/mined
Prior to commit 433d6423c3
commands
Change-Id: I374ab3ff0e3b9e47779fc21e80b47fda87698242
__STDC__ is used to mitigate the differences between K&R C and the
ANSI C standard. Nearly every compiler now supports ANSI C, so
there is no need to support non-standard compilers.
Change-Id: Ifc3381ecf1c43dfde9004bee48552d8b3ac4dcdc
* Remove undef NULL, EOF, getchar, putchar
* Rename putchar, getchar, _putchar, _getchar to putch, getch, _putch,
_getch to avoid conflict with libc functions.
* Rename UP() to UP1() (for UP 1 line) to avoid conflict with UP
definition in termcap.h. Rename DN1 LF1 RT1 for consistency.
* Add termcap.h for prototypes for tputs and friends.
* Add libterminfo references to Makefile
* Add return value to _putch() to make it work as tputs expects.
* Make putch() call _putch()
* Remove UNIX ifdefs and all code in the !UNIX branches.
closes#43
Change-Id: I0a6f7298aa8b12a74225badc88d3c236a02669ea
Removes the following man pages:
* awk.1x -- for a version of awk we no longer have
* kermit.1x -- seems gone altogether
* macros.1x -- not useful for anyone anymore
Moves the following man pages:
* mined.1x -- Moved to minix/commands/mined/mined.1
and reformatted to use the mdoc macros instead of the
Minix macros so that it displays properly.
Removes /usr/man/man1x from the directory tree.
closes#44
Change-Id: I59b8bd54cf5cba6d188e51e99a92b36e90c275c1
The escape sequences for the function keys used to be separated
out in older versions of Minix when they were different for m68k
and intel. Support for m68k was dropped and that code was
removed, leaving the ifdef i386. Since the sequences are the
same for i386 and arm, there is no need to keep the ifdef i386.
Change-Id: Id96a80bcb24da120efa63acc9b248d87fc347eac
It used to refer to several NIL_* definitions. Those were removed
in commit 6e25ad8b0a leaving the
comment with nothing to comment on.
Change-Id: I52221ae5d2c5216e82391b480cf2038ad723b8f0
Fix dead code block, make surrounding code more readable, and remove
unused mode variable.
closes#20
Change-Id: I802e3d8680d7a7adc7acd580bfcec9dc28af0bc4
Bochs has switched from port base 0x240 to 0x300 for its default
NE2000 ISA configuration, and QEMU is using the same settings.
Change-Id: Ide6cdb14321eb4324d0bf6d6314c5970b3493e95
The jump-to-start hack is not resetting global variables, resulting in
a crash after several such restarts cause an overflow in the network
table. This patch fixes that particular issue, but more similar
issues (in particular memory leaks) are bound to come up. As such this
is a stopgap measure until we can get rid of the old dhcpd altogether.
This resolves the additional issue reported in #2.
Change-Id: Ic4cd80eae520cf2b97e893bac63b3ab1ecfea6d8
The entire infrastructure relied on an ACK feature, and as such, it
has been broken for years now, with no easy way to repair it.
Change-Id: I783c2a21276967af115a642199f31fef0f14a572
- synchronize request type with ioctl by making it unsigned long;
- unbreak VFS requests, as they were being sent to PM;
- use proper ioctl direction flags (and new numbers) for requests;
- remove some needless header inclusions;
- svrctl is in libc, make its message name reflect this;
- keep backward compatibility: svrctl is part of the userland ABI.
Change-Id: I44902e8d0d11b8ebc1ef3bda94d2202481743c9b
