Re: libfdt: check return value of fdt_num_mem_rsv() in fdt_pack()

[Markus Elfring <Markus.Elfring@web.de>]

>>> fdt_num_mem_rsv() may return -FDT_ERR_TRUNCATED.
>>> In this case fdt_pack() should propagate the error code.
>>
>> 1. Please choose imperative wordings for an improved change description.
>>    https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.10-rc6#n94
>
> The current subject is an imperative?

Yes.

The requirement for “imperative mood” affects mostly the commit message (or “changelog”),
doesn't it?


>> 2. Would you like to add any tags (like “Fixes” and “Cc”)?
>
> d5db5382c5e5 ("libfdt: Safer access to memory reservations") introduced the check that returns the error code. But before that we could simply overrun the buffer.

Would an other commit be a more appropriate reference?


> I would not know which patch to blame.

Please take another look at a corresponding information source:
https://github.com/dgibson/dtc/blame/main/libfdt/fdt_rw.c#L487-L500

Update candidate:
libfdt: Handle v16 and re-ordered trees for r/w
2007-11-01
https://github.com/dgibson/dtc/commit/a041dcdc48453f26b76bccdb5e2a1ebb3a0ea987#diff-1a98f2be127ff35ab7183bdae1e010189c9992b3bd6e6779fa7b7e451bf72ac4R382


> Whom do you want to Cc?

I suggest to take another look at corresponding information sources.

* https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/stable-kernel-rules.rst?h=v6.10-rc6#n34

* https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.10-rc6#n458


>> 3. How do you think about to use a summary phrase like “Complete error handling
>>    in fdt_pack()”?
>
> Why should I choose a less specific subject?

You would like to improve the error detection and corresponding exception handling another bit,
wouldn't you?

* https://cwe.mitre.org/data/definitions/252.html

* https://wiki.sei.cmu.edu/confluence/display/c/EXP12-C.+Do+not+ignore+values+returned+by+functions


Regards,
Markus