Re: [PATCH 1/3] git_parse_unsigned: reject negative values
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Oct 21, 2022, 18:09 UTC
- Message-ID
- <xmqqbkq5kq0m.fsf@gitster.g>
- In-Reply-To
- <9c8440e5e82777311c6217cb4a9ddcd5cb8ce689.1666359915.git.gitgitgadget@gmail.com>
"Phillip Wood via GitGitGadget" <gitgitgadget@gmail.com> writes:
Show 8 quoted lines
> From: Phillip Wood <phillip.wood@dunelm.org.uk> > > git_parse_unsigned() relies on strtoumax() which unfortunately parses > negative values as large positive integers. Fix this by rejecting any > string that contains '-' as we do in strtoul_ui(). I've chosen to treat > negative numbers as invalid input and set errno to EINVAL rather than > ERANGE one the basis that they are never acceptable if we're looking for > a unsigned integer.
And the code now would reject something like "43-21" because it does not insist that "-" must be used for a sign, so it makes EINVAL doubly appropriate, I would think. In the original code, "43-21" would have been parsed as "43" (by strtoumax) followed by "-" (which is rejected by get_unit_factor() and yielded EINVAL, so this change would not change the behaviour for such an input, if we receive EINVAL when we see a "-".
A devil's advocate would consider if we ever want to have a unit factor that has "-" in it (e.g. "10000e-3" == 10). I can buy it if we want to declare that it is not worth supporting.
Show 21 quoted lines
> Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
> ---
> config.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/config.c b/config.c
> index cbb5a3bab74..d5069d4f01d 100644
> --- a/config.c
> +++ b/config.c
> @@ -1193,6 +1193,11 @@ static int git_parse_unsigned(const char *value, uintmax_t *ret, uintmax_t max)
> uintmax_t val;
> uintmax_t factor;
>
> + /* negative values would be accepted by strtoumax */
> + if (strchr(value, '-')) {
> + errno = EINVAL;
> + return 0;
> + }
> errno = 0;
> val = strtoumax(value, &end, 0);
> if (errno == ERANGE)