Add MBEDTLS_ERR_XXX_HW_ACCEL_FAILED error codes for all cryptography
modules where the software implementation can be replaced by a hardware
implementation.
This does not include the individual message digest modules since they
currently have no way to return error codes.
This does include the higher-level md, cipher and pk modules since
alternative implementations and even algorithms can be plugged in at
runtime.
The race goes this way:
1. ssl_recv() succeeds (ie no signal received yet)
2. processing the message leads to aborting handshake with ret != 0
3. reset ret if we were signaled
4. print error if ret is still non-zero
5. go back to net_accept() which can be interrupted by a signal
We print the error message only if the signal is received between steps 3 and
5, not when it arrives between steps 1 and 3.
This can cause failures in ssl-opt.sh where we check for the presence of "Last
error was..." in the server's output: if we perform step 2, the client will be
notified and exit, then ssl-opt.sh will send SIGTERM to the server, but if it
didn't get a chance to run and pass step 3 in the meantime, we're in trouble.
The purpose of step 3 was to avoid spurious "Last error" messages in the
output so that ssl-opt.sh can check for a successful run by the absence of
that message. However, it is enough to suppress that message when the last
error we get is the one we expect from being interrupted by a signal - doing
more could hide real errors.
Also, improve the messages printed when interrupted to make it easier to
distinguish the two cases - this could be used in a testing script wanted to
check that the server doesn't see the client as disconnecting unexpectedly.
Change function in tests named mbedtls_entropy_func to
mbedtls_test_entropy_func to avoid getting error from the linker when
calling the mbedtls_entropy_func elsewhere.
This commit allows users to provide alternative implementations of the
ECJPAKE interface through the configuration option MBEDTLS_ECJPAKE_ALT.
When set, the user must add `ecjpake_alt.h` declaring the same
interface as `ecjpake.h`, as well as add some compilation unit which
implements the functionality. This is in line with the preexisting
support for alternative implementations of other modules.
The corner cases fixed include:
* Allocating a buffer of size 0. With this change, the allocator now
returns a NULL pointer in this case. Note that changes in pem.c and
x509_crl.c were required to fix tests that did not work under this
assumption.
* Initialising the allocator with less memory than required for headers.
* Fix header chain checks for uninitialised allocator.
Remove the copyright block from the Doxygen comments, to clean up the
detailed description in the generated Doxygen output. Also, add \file and
\brief tags to all headers in doxygen/input.
