Previously an incorrect length value was passed to both
gsm_7bit_decode_n_ussd() and gsm_7bit_encode_n_ussd()
functions during test_7bit_ussd() execution, due to:
octets_written = strlen(decoded);
The problem is that a 7-bit encoded string takes less memory
than its 8-bit equivalent. So, here strlen() returns one-byte
bigger value, that octets_written is. This then causes the
uninitialized memory access.
Found using Valgrind:
Conditional jump or move depends on uninitialised value(s)
at 0x506DCCC: gsm_7bit_decode_n_ussd (gsm_utils.c:248)
by 0x40134B: test_7bit_ussd (ussd_test.c:104)
by 0x400F5D: main (ussd_test.c:161)
Conditional jump or move depends on uninitialised value(s)
at 0x506DBB7: gsm_7bit_decode_n_hdr (gsm_utils.c:220)
by 0x506DC9E: gsm_7bit_decode_n_ussd (gsm_utils.c:246)
by 0x40134B: test_7bit_ussd (ussd_test.c:104)
by 0x400F5D: main (ussd_test.c:161)
Conditional jump or move depends on uninitialised value(s)
at 0x506DBCB: gsm_septet_lookup (gsm_utils.c:153)
by 0x506DBCB: gsm_7bit_decode_n_hdr (gsm_utils.c:224)
by 0x506DC9E: gsm_7bit_decode_n_ussd (gsm_utils.c:246)
by 0x40134B: test_7bit_ussd (ussd_test.c:104)
by 0x400F5D: main (ussd_test.c:161)
Change-Id: Ic31805b6a5a917dfc6284edba6ffdd21246ac20c
bd33a9568e