In the "match attribute" branch of coap_print_wellknown_lkd(), an
attribute value shorter than 2 bytes (e.g. a lone " registered via
coap_add_attr()) causes attr->value->s[0] == '"' to read past the
value, and unquoted_val.length -= 2 to underflow the size_t length
to SIZE_MAX. The resulting bogus coap_str_const_t is then passed to
match(), which dereferences memory far outside the original buffer.
Guard the quote-check on length >= 2 before reading s[0], mirroring
the length && ... guard already used a few lines above for
query_pattern (added in #1977) and the trailing-'*' guard next to
it.
Reproduced with a standalone harness placing a 1-byte attribute
value at the end of a guard-paged region: pre-fix, unquoted_val.length
becomes SIZE_MAX and match() crashes on the guard page; post-fix,
length stays at the original value (no underflow) and match() safely
short-circuits. A normal quoted value ("foo", 5 bytes) still strips
to foo (3 bytes) unchanged, confirming no regression.
Clean up duplicate MID handling, and just send back last response if MID
matches.
Removed COAP_BLOCK_CACHE_RESPONSE as no longer required for duplicate MID
handling, and so no need to send an Empty ACK response for a subsequent
Separate response as a referenced copy of the last PDU respponse is now kept
for a session.
Note that if a request is sent by a proxy to an upstream server, this always
converts the upstream server's response into a Separate response back to the
client as the upstream server may take time to respond, do any error recovery
etc.
This allows (D)TLS1.3 to be negotiated when using PSK.
If '-i match_identity_file' is being used, the hint is taken from the first
entry if not otherwise defined by '-h hint'.
Compiling with gcc-16.1.1 and glibc-2.43 yields warnings: "initialization
discards ‘const’ qualifier from pointer target type".
Indeed, pointer passed to strchr() is `const char *` and memory pointed by
return value of strchr() is never modified, so variable to assign return
value should be `const char *`.
New ./configure option
--with-mbedtls-oscore
If --disable-dtls is set, then MbedTLS is used as the OSCORE backend, otherwise
the MbedTLS library is used for both (D)TLS and OSCORE.
New cmake option
-DOSCORE_BACKEND=mbedtls
If -DENABLE_DTLS=OFF is set, then MbedTLS is used as the OSCORE backend, otherwise
the MbedTLS library is used for both (D)TLS and OSCORE.
New Zephyr option
config MBEDTLS_OSCORE
If set to y and CONFIG_LIBCOAP_OSCORE_SUPPORT is set to y, then the Zephyr MbedTLS
backend will get used for the OSCORE backend (no (D)TLS).
Jon Shallow