tree e5e21d18023da3245069e0ef54cc314be743c6fc
parent 30eb8ca6aaf265675b0e73e903a84646a9320699
author Philipp Maier <pmaier@sysmocom.de> 1589226116 +0200
committer Philipp Maier <pmaier@sysmocom.de> 1590146295 +0200

utils: do not crash when all bytes of EF.IMSI are 0xFF

In case try to decode the contents of an uninitalized EF.IMSI, the
function dec_imsi() would crash because it truncates all 0xFF from the
swapped version of the EF.IMSI contents and then accesses the first
element of the buffer. This always works for EF.IMSI contents that
contain valid IMSI data, but if all bytes are set to 0xFF, then no data
is left in the buffer after truncating, so lets check if we even have
bytes left before we move on with the decoding.

Change-Id: I93874a1d7e0b87d39e4b06a5c504643cfabb451c