When MBEDTLS_MEMORY_BUFFER_ALLOC_C was defined, the sample ssl_server2.c was
using its own memory buffer for memory allocated by the library. The memory
used wasn't obvious, so this adds a macro for the memory buffer allocated to
make the allocated memory size more obvious and hence easier to configure.
Added an additional i386 test to all.sh, to allow one test with -O0 which
compiles out inline assembly, and one to test with -01 which includes the inline
assembly.
The i386 test builds were only building the default configuration and had
no address sanitisation. This commit expands the test configuration to the full
configuration in all.sh and builds with ASan for when the test suites are
executed.
Newer features in the library have increased the overall RAM usage of the
library, when all features are enabled. ssl_server2.c, with all features enabled
was running out of memory for the ssl-opt.sh test 'Authentication: client
max_int chain, server required'.
This commit increases the memory buffer allocation for ssl_server2.c to allow
the test to work with all features enabled.
Added a section on API/ABI compatibility on the development branch to the
CONTRIBUTING.md guidelines. Also added to the testing section, refined the LTS
section and changed some formatting for consistency.
When calling all.sh from a script and using "--keep-going", errors were
sometimes missed due to all.sh always returning 0 "success" return code.
Return 1 if there is any failure encountered during a "keep-going" run.
The purpose of the networking module can sometimes be misunderstood. This adds
a definition and explanation of what the networking module is and what it can be
used for.
We don't compile in the assembly code if compiler optimisations are disabled as
the number of registers used in the assembly code doesn't work with the -O0
option. Also anyone select -O0 probably doesn't want to compile in the assembly
code anyway.
The length to the debug message could conceivably leak through the time it
takes to print it, and that length would in turn reveal whether padding was
correct or not.
The basis for the Lucky 13 family of attacks is for an attacker to be able to
distinguish between (long) valid TLS-CBC padding and invalid TLS-CBC padding.
Since our code sets padlen = 0 for invalid padding, the length of the input to
the HMAC function, and the location where we read the MAC, give information
about that.
A local attacker could gain information about that by observing via a
cache attack whether the bytes at the end of the record (at the location of
would-be padding) have been read during MAC verification (computation +
comparison).
Let's make sure they're always read.
The basis for the Lucky 13 family of attacks is for an attacker to be able to
distinguish between (long) valid TLS-CBC padding and invalid TLS-CBC padding.
Since our code sets padlen = 0 for invalid padding, the length of the input to
the HMAC function gives information about that.
Information about this length (modulo the MD/SHA block size) can be deduced
from how much MD/SHA padding (this is distinct from TLS-CBC padding) is used.
If MD/SHA padding is read from a (static) buffer, a local attacker could get
information about how much is used via a cache attack targeting that buffer.
Let's get rid of this buffer. Now the only buffer used is the internal MD/SHA
one, which is always read fully by the process() function.
The CONTRIBUTING.md referred to 'legacy' branches instead of LTS branches, and
also referenced mbedtls-1.3 which is no longer maintained, and omitted
mbedtls-2.7 which is.
