Re: [PATCH 2/4] archive-tar: fix pax extended header length calculation
On Sat, Aug 17, 2019 at 12:24 PM René Scharfe <l.s.r@web.de> wrote:
> A pax extended header records starts with a decimal number. Its value
> is the length of the whole record, including its own length.
>
> The calculation of that number if strbuf_append_ext_header() is off by
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> one in case the length of the rest is close to a higher order of
> magnitude. This affects paths and link targets a bit shorter than 1000,
> 10000, 100000 etc. characters -- paths with a length of up to 100 fit
> into the tar header and don't need a pax extended header.
>
> The mistake has been present since the function was added by ae64bbc18c
> ("tar-tree: Introduce write_entry()", 2006-03-25).
>
> Account for digits added to len during the loop and keep incrementing
> until we have enough space for len and the rest. The crucial change is
> to check against the current value of len before each iteration, instead
> of against its value before the loop.
>
> Signed-off-by: René Scharfe <l.s.r@web.de>Eric Sunshine <sunshine@sunshineco.com>