C SDK / Error in internal_socket_read when processing chunked responses

andinux commented 2 months ago

I found an error on the C cli when processing a chunked response from the server. I'm able to reproduce the issue only when the server runs in insecure mode. Minimal environment to make it happen:

run the core locally with insecure flag
connect with the cli
run CREATE DATABASE db1.sqlite; CREATE DATABASE db2.sqlite
run SET CLIENT KEY MAXROWS TO 2
run LIST DATABASES

The server send the following buffers

/43 1:1 2 1
+4 name+10 db1.sqlite+10 db2.sqlite
/6 0 0 0

If the client reads from the socket each one of the 3 packets individually or the first 2 in a single read and the third in a following read (like it seems to always happpen with TLS), the sdk/cli works fine. Otherwise, if the sdk/cli reads all the received data in a single read (like it frequently happens without TLS) then it fires an error in internal_socket_read. The issue is in sqcloud.c lines 1470-1480:

           if (clen + cstart + 1 != tread) {
                // check buffer allocation and continue reading
                if (clen + cstart - tread > blen) {
                ...
                blen = (clen + cstart + 1) - tread;

because in this case tread includes the end chunk (it's value is 56) but clen + cstart + 1 only consider the real content (43+3+1 = 47) and the following blen = (clen + cstart + 1) - tread; is lower than 0 but the value is uint64 so it's value is represented as 4294967287 and the following read will fail with error code 22 Invalid argument because of this blen value.

marcobambini commented 2 months ago

Fixed by https://github.com/sqlitecloud/sdk/commit/a4835577ab84292d924dd636839d4fb391138ce6

sqlitecloud / sdk

C SDK / Error in internal_socket_read when processing chunked responses #9