nasa / CF

The Core Flight System (cFS) CFDP application.
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CF invokes CFE_MSG_Init with size of 0 #401

Closed jphickey closed 1 year ago

jphickey commented 1 year ago

Checklist (Please check before submitting)

Describe the bug The 3rd parameter of CFE_MSG_Init() is supposed to indicate the actual size of the structure/buffer being initialized. In general, this must be at least the size of the primary header in order to be valid.

CF (at first) passes this as 0, then overwrites this with the real size later on.

The problem is, a size of 0 is totally invalid, and to be correct, CFE_MSG_Init() should not be writing any values into a structure that is smaller than the size of a primary header, as this is an error. Writing any value into a struct of size 0 is a write-beyond-bounds error, and thus the fact that the default CFE_MSG_Init() even allows this is a bug.

To Reproduce Run CF with a proper implementation of CFE_MSG_Init() - i.e. one that verifies the size is valid. When passed a size of 0, none of the header fields will be set (correct behavior). This results in the buffer being in an indeterminate state, and the MsgId will not be set.

Expected behavior The MsgId needs to be set by the call to CFE_MSG_Init

Code snips https://github.com/nasa/CF/blob/38cfee8a2284fc7605e6fb2b2556b528dcf62499/fsw/src/cf_cfdp_sbintf.c#L120-L121

Reporter Info Joseph Hickey, Vantage Systems, Inc.