we cannot retry posts and we do not know for sure if a
post had any side effect when we got no status, so always
make a new connection for a post request.
when dragging a window edge, allow one to slide to a corner
or slide from corner to corner (usefull when inverting).
also make sure the right or bottom of the rectangle returned
by whichrect() is not outside of the screen (which makes
drawing slow).
we can encrypt the 256 bit chacha key on each invocation
making it hard to reconstruct previous outputs of the
generator given the current state (backtracking resiatance).
the kernels custom rand() and nrand() functions where not working
as specified in rand(2). now we just use libc's rand() and nrand()
functions but provide a custom lrand() impelmenting the xoroshiro128+
algorithm as proposed by aiju.
we now access the user buffer in randomread() outside of the lock,
only copying and advancing the chacha state under the lock. this
means we can use randomread() within the fault handling path now
without fearing deadlock. this also allows multiple readers to
generate random numbers in parallel.
we might wake up on a different cpu after the sleep so
delta from machX->ticks - machY->ticks can become negative
giving spurious timeouts. to avoid this always use the
same mach 0 tick counter for the delta.
the manpage states that capabilities time out after a minute,
so we add ticks field into the Caphash struct and record the
time when the capability was inserted. freeing old capabilities
is handled in trimcaps(), which makes room for one extra cap
and frees timed out ones.
we also limit the capuse write size to less than 1024 bytes to
prevent denial of service as we have to copy the user buffer.
(memory exhaustion).
we have to check the from user *before* attempting to remove
the capability! the wrong user shouldnt be able to change any
state. this fixes the memory leak of the caphash.
do the hash comparsion with tsmemcmp(), avoiding timing
side channels.
allocate the capabilities in secret memory pool to prevent
debugger access.
previously, right shift >>0 resulted in >>32 being emited. this
is especially problematic when the shift count comes from a macro
expansion.
we now handle constant shift >>0 as <<0 (no shift) and allow
shift by 32 be specified.
this applies to logical right shift (>>) arithmetic right shift (->)
and right rotate (@>).
the prior implementation was unneccesarily complicated for
no good reason due to me misunderstanding how libc's nrand()
works. in contrast to libc, we already generate the *closest*
power-of-2 random number with mprand() in the sampling loop.
The kernel needs to keep cryptographic keys and cipher states
confidential. secalloc() allocates memory from the secret pool
which is protected from debuggers reading the memory thru devproc.
secfree() releases the memory, overriding the data with garbage.
drawterm, factotum, secstore and the auth commands
all had ther own implementation of readcons. we
want to have one common function for this to avoid
the duplication, so putting that in libauthsrv.
introduce PASSWDLEN which makes the use more explicit
than ANAMELEN.
when we get eof, stop the loop immidiately and do not
rely on the read to eventually return an error.
when convM2S() fails to decode the message, error out
and stop the loop. there is no point in continuing.
given that the memory leaks have been fixed, theres no need
for the obscure restart feature which is not reliable anyway.
remove the code updating procname on each 9p request.
handle convM2S error by exiting the service loop, dont read
9p channel after eof.
we used to not sign extend if the destination was unsigned
uvlong, which is wrong. we have to sign extend only based
on the signedness of the source (it gets propagated to vlong)
this bug hit in hjfs in the newentry() function, causing file
creation to fail with "create -- phase error":
newentry(...)
{
uvlong sj;
int si;
...
sj = si = -1;
...
}
