Heap buffer overflow when using the mkspell command

[Yegappan Lakshmanan]

Hi,

When generating a spell file using the ":mkspell" command,

I am running into a heap buffer overflow (with the ASAN build):

To reproduce this problem, save the following content to

a file (x.vim):

-------------------------------------------------------------------------------------

call writefile(['1', 'work'], 'Xtest.dic')
call writefile(['SOFOFROM abcd', 'SOFOTO ABCD', 'SAL CIA X'], 'Xtest.aff')
mkspell! Xtest.spl Xtest

-------------------------------------------------------------------------------------  

Now run the command "vim --clean -N -u NONE -i NONE -S x.vim"

- Yegappan

[Bram Moolenaar]

I can also find it with valgrind.

Looks like we need to remember the length of the bytes buffer, so we can
avoid going over the end.


--
Ten bugs in the hand is better than one as yet undetected.

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