the problem is that side() gives a false positive on the OCOND
with later constant folding eleminating the acutal side effect
and OCAST ending up with two nested OCATS with the nested one
being zapped (type == T).
kernel: make exec clear errstr, stop side-channels and truncate on utf8 boundary
make exec() clear the per process error string
to avoid spurious errors and confusion.
the errstr() syscall used to always swap the
maximum buffer size with memmove(), which is
problematic as this gives access to the garbage
beyond the NUL byte. worse, newproc(), werrstr()
and rerrstr() only clear the first byte of the
input buffer. so random stack rubble could be
leaked across processes.
we change the errstr() syscall to not copy
beyond the NUL byte.
the manpage also documents that errstr() should
truncate on a utf8 boundary so we use utfecpy()
to ensure proper NUL termination.
cinap_lenrek [Fri, 30 Aug 2019 05:34:35 +0000 (07:34 +0200)]
auth/rsa2asn1: implement private key export with -a flag (thanks kvik)
kvik writes:
I needed to convert the RSA private key that was laying around in
secstore into a format understood by UNIX® tools like SSH.
With asn12rsa(8) we can go from the ASN.1/DER to Plan 9 format, but not
back - so I wrote the libsec function asn1encodeRSApriv(2) and used it in
rsa2asn1(8) by adding the -a flag which causes the full private key to be
encoded and output.
cinap_lenrek [Thu, 29 Aug 2019 05:35:22 +0000 (07:35 +0200)]
pc64: map kernel text readonly and everything else no-execute
the idea is to catch bugs and make kernel exploitation
harder by mapping the kernel text section readonly
and everything else no-execute.
l.s maps the KZERO address space using 2MB pages so
to get the 4K granularity for the text section we use
the new ptesplit() function to split that mapping up.
we need to set EFER no-execute enable bit early
in apbootstrap so secondary application processors
will understand the NX bit in our shared kernel page
tables. also APBOOTSTRAP needs to be kept executable.
rebootjump() needs to mark REBOOTADDR page executable.
cinap_lenrek [Tue, 27 Aug 2019 04:16:20 +0000 (06:16 +0200)]
kernel: prohibit changing cache attributes (SG_CACHED|SG_DEVICE) in segattach(), set SG_RONLY in data2txt()
the user should not be able to change the cache
attributes for a segment in segattach() as this
can cause the same memory to be mapped with
conflicting attributes in the cache.
SG_TEXT should always be mapped with SG_RONLY
attribute. so fix data2txt() to follow the rules.
cinap_lenrek [Tue, 27 Aug 2019 01:47:18 +0000 (03:47 +0200)]
kernel: catch execution read fault on SG_NOEXEC segment
fault() now has an additional pc argument that is
used to detect fault on a non-executable segment.
that is, we check on read fault if the segment
has the SG_NOEXEC attribute and the program counter
is within faulting page.
cinap_lenrek [Mon, 26 Aug 2019 20:34:38 +0000 (22:34 +0200)]
kernel: expose no execute bit to portable mmu code as SG_NOEXEC / PTENOEXEC, add PTECACHED bits
a portable SG_NOEXEC segment attribute was added to allow
non-executable (physical) segments. which will set the
PTENOEXEC bits for putmmu().
in the future, this can be used to make non-executable
stack / bss segments.
the SG_DEVICE attribute was added to distinguish between
mmio regions and uncached memory. only matterns on arm64.
on arm, theres the issue that PTEUNCACHED would have
no bits set when using the hardware bit definitions.
this is the reason bcm, kw, teg2 and omap kernels use
arteficial PTE constants. on zynq, the XN bit was used
as a hack to give PTEUNCACHED a non-zero value and when
the bit is clear then cache attributes where added to
the pte.
to fix this, PTECACHED constant was added.
the portable mmu code in fault.c will now explicitely set
PTECACHED bits for cached memory and PTEUNCACHED for
uncached memory. that way the hardware bit definitions
can be used everywhere.
on the 2GB and 4GB raspberry pi 4 variants, there are two
memory regions for ram:
[0x00000000..0x3e600000)
[0x40000000..0xfc000000)
the framebuffer is somewhere at the end of the first
GB of memory.
to handle these, we append the region base and limit
of the second region to *maxmem= like:
*maxmem=0x3e600000 0x40000000 0xfc000000
the mmu code has been changed to have non-existing
ram unmapped and mmukmap() now uses small 64K pages
instead of 512GB pages to avoid aliasing (framebuffer).
the VIRTPCI mapping has been removed as we now have
a proper vmap() implementation which assigns vritual
addresses automatically.
bcm, bcm64: make irq.$O optional and add intrdisable(), use intrenable()
the raspberry pi 4 has a new interrupt controller and
pci support, so get rid of intrenable() macro and
properly make intrenable function with tbdf argument.
bcm64: strip debug symbols to make sure .img file is multiple of 4 bytes
the raspberry pi4 firmware refuses to enable the GIC interrup controller
for arm64 when the .img file is not a multiple of 4 bytes. yes, this
is insane and nowhere documented.
bcm, bcm64: add support for device tree parameter passing
the new raspberry pi 4 firmware for arm64 seems to have
broken atag support. so we now parse the device tree
structure to get the bootargs and memory configuration.
Ori Bernstein had Sunrise Point-H USB 3.0 xHCI Controller that would mysteriously
crash on the 5th ENABLESLOT command. This was reproducable by even just allocating
slots in a loop right after init.
It turns out, the 1.2 spec extended the Max Scratchpad Buffers in HCSPARAMS2 so our
driver would not allocate enougth scratchpad buffers and controller firmware would
crash once it went beyond our allocated scratchpad buffer array.
This change also fixes:
- ignore bits 16:31 in PAGESIZE register
- preserve bits 10:31 in the CONFIG register
- handle ADDESSDEV command failure (so it can be retried)
cinap_lenrek [Fri, 28 Jun 2019 16:12:13 +0000 (18:12 +0200)]
pc64: preallocate mmupool page tables
preallocate 2% of user pages for page tables and MMU structures
and keep them mapped in the VMAP range. this leaves more space
in the KZERO window and avoids running out of kernel memory on
machines with large amounts of memory.
cinap_lenrek [Mon, 24 Jun 2019 17:36:01 +0000 (19:36 +0200)]
8c, 6c: avoid allocating index registers when we don't have to
when a operation receives a chain of OINDEX nodes as its operands,
each indexing step used to allocate a new index register. this
is wastefull an can result in running out of fixed registers on 386
for code such as: x = a[a[a[a[i]]]].
instead we attempt to reuse the destination register of the operation
as the index register if it is not otherwise referenced. this results
in the index chain to use a single register for index and result and
leaves registers free to be used for something usefull instead.
for 6c, try to avoid R13 as well as BP index base register.
Ori Bernstein [Fri, 21 Jun 2019 17:00:58 +0000 (10:00 -0700)]
Turn on warnings when building libap.
For ape, we never enabled warnings in cflags.
Turning it on brings up a lot of warnings. Most are noise,
but a few caught unused variables and trunctaions of pointers.
to smaller integers (int, long).
0
size_from size_step size_to {
buffersizes exch 2 index exch put
1 add
} for
pop
/buffers buffercount array def
0 1 buffercount 1 sub {
/ind exch def
buffersizes ind get /cursize exch def
cursize string /curbuf exch def
buffers ind curbuf put
cursize 16 sub 1 cursize 1 sub {
curbuf exch 255 put
} for
} for
{
.eqproc
buffersearchvars 0 buffersearchvars 0 get 1 add put
buffersearchvars 1 0 put
buffersearchvars 2 0 put
buffercount {
buffers buffersearchvars 1 get get
buffersizes buffersearchvars 1 get get
16 sub get
254 le {
buffersearchvars 2 1 put
buffersearchvars 3 buffers buffersearchvars 1 get get put
buffersearchvars 4 buffersizes buffersearchvars 1 get get 16 sub put
} if
buffersearchvars 1 buffersearchvars 1 get 1 add put
} repeat
buffersearchvars 2 get 1 ge {
exit
} if
%(.) print
} loop
.eqproc
.eqproc
.eqproc
sdevice 0
currentdevice
buffersearchvars 3 get buffersearchvars 4 get 16#7e put
buffersearchvars 3 get buffersearchvars 4 get 1 add 16#12 put
buffersearchvars 3 get buffersearchvars 4 get 5 add 16#ff put
put
under heavy load, factotum can return a "too much activity" error,
which upas/smtpd and upas/smtp should consider a temporary error
instead of a permanent one.
cinap_lenrek [Wed, 19 Jun 2019 20:58:16 +0000 (22:58 +0200)]
cwfs: properly handle 64 bit qid path
for historical reasons, kenfs stores directory entries in pre 9p2000
format with directories having the QPDIR bit 31 set in the qid path.
however, the 64 bit fileserver allows 64 bit qid paths.
given that we do not support pre 9p2000 clients and do not rely on
the QPDIR, but want to keep the block check tags consistent, we will
*INVERT* the QPDIR bit in directory entry qid paths for directories.
this preserves the on-disk semantics (for < 31 bit qmax) but does
not complicate qid generation and recovery. also makes it easy to
convert between directory entry qid and 9p format.
Ori Bernstein [Wed, 19 Jun 2019 05:47:15 +0000 (22:47 -0700)]
Always turn on the -+ flag in cpp
C99 comments have been the default in compilers for something like 20 years
now. This means we don't need to remember to turn it on when porting software,
and gets rid of cryptic errors about unterminated character constants when
someone writes something like:
// Didn't need to...
We still accept the flag to avoid breaking mkfiles, but we do nothing with it.
This also removes the documentation, since the option does nothing now.
Ori Bernstein [Wed, 19 Jun 2019 05:17:19 +0000 (22:17 -0700)]
Import compiler warnings and bugfixes from Charles.
This change imports a few warnings and minor fixes from Charles branch
here: https://bitbucket.org/plan9-from-bell-labs/plan9.
The changes included here:
changeset: 1374:9185dc017be0
summary: declare castucom; move a declaration into order;
use cast instead of ULL suffix
changeset: 1353:5fe8380b1818
summary: supporting functions:
1. castucom to match unlikely mask operation;
2. be sure to snap both sides of pointer subtraction completely;
3. add extra operators as side-effect free
changeset: 1352:90058c092d66
summary: 1. correct result type for mixed-mode assignment operators
2. detect divide by zero (erik);
3. detect masks misformed by sign-extension;
4. diagnose mixed old/new prototypes