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| author | Vadim Yanitskiy <axilirator@gmail.com> | 2019-08-29 14:53:47 +0200 |
|---|---|---|
| committer | Vadim Yanitskiy <axilirator@gmail.com> | 2019-08-29 15:04:28 +0200 |
| commit | df86074abe59543a8f4d245978d27d8ba1141089 (patch) | |
| tree | 41cc073a988b82911eb6a1de0b871bf7ea558385 | |
| parent | 5fed799df38a1c9327b809a22f65b9b5c55022fe (diff) | |
trx_toolkit/data_msg.py: fix message length check in parse_msg()
Unlike DATA_MSG.HDR_LEN, the CHDR_LEN is a constant that defines
length of the common header, which is mandatory for every version.
DATA_MSG.HDR_LEN in its turn defines length of the whole header,
including the version specific fields. Thus we need to know the
header version before using it.
In DATA_MSG.parse_msg() we need to parse the common header first,
so then we know the version and length of the whole header. After
that we can safely use DATA_MSG.HDR_LEN.
Change-Id: I2809f5f96209eed64bdabf7a15575144313f7cc9
| -rw-r--r-- | src/target/trx_toolkit/data_msg.py | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/src/target/trx_toolkit/data_msg.py b/src/target/trx_toolkit/data_msg.py index a1046ec9..c5d284df 100644 --- a/src/target/trx_toolkit/data_msg.py +++ b/src/target/trx_toolkit/data_msg.py @@ -275,9 +275,9 @@ class DATAMSG: # Parses a TRX DATA message def parse_msg(self, msg): - # Make sure we have at least header - if len(msg) < self.HDR_LEN: - raise ValueError("Message is to short") + # Make sure we have at least common header + if len(msg) < self.CHDR_LEN: + raise ValueError("Message is to short: missing common header") # Parse version and TDMA TN self.ver = (msg[0] >> 4) @@ -286,6 +286,11 @@ class DATAMSG: # Parse TDMA FN self.fn = struct.unpack(">L", msg[1:5])[0] + # Make sure we have the whole header, + # including the version specific fields + if len(msg) < self.HDR_LEN: + raise ValueError("Message is to short: missing version specific header") + # Specific message part self.parse_hdr(msg) |