sha1-name: check for overflow of N in "foo^N" and "foo~N"

Reject values that don't fit into an int, as get_parent() and
get_nth_ancestor() cannot handle them.  That's better than potentially
returning a random object.

If this restriction turns out to be too tight then we can switch to a
wider data type, but we'd still have to check for overflow.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
René Scharfe 2019-09-15 14:10:28 +02:00 коммит произвёл Junio C Hamano
Родитель a678df1bf9
Коммит 59fa5f5a25
2 изменённых файлов: 14 добавлений и 5 удалений

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@ -1163,13 +1163,22 @@ static enum get_oid_result get_oid_1(struct repository *r,
}
if (has_suffix) {
int num = 0;
unsigned int num = 0;
int len1 = cp - name;
cp++;
while (cp < name + len)
num = num * 10 + *cp++ - '0';
while (cp < name + len) {
unsigned int digit = *cp++ - '0';
if (unsigned_mult_overflows(num, 10))
return MISSING_OBJECT;
num *= 10;
if (unsigned_add_overflows(num, digit))
return MISSING_OBJECT;
num += digit;
}
if (!num && len1 == len - 1)
num = 1;
else if (num > INT_MAX)
return MISSING_OBJECT;
if (has_suffix == '^')
return get_parent(r, name, len1, oid, num);
/* else if (has_suffix == '~') -- goes without saying */

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@ -215,11 +215,11 @@ test_expect_success 'arg before dashdash must be a revision (ambiguous)' '
test_cmp expect actual
'
test_expect_failure 'reject Nth parent if N is too high' '
test_expect_success 'reject Nth parent if N is too high' '
test_must_fail git rev-parse HEAD^100000000000000000000000000000000
'
test_expect_failure 'reject Nth ancestor if N is too high' '
test_expect_success 'reject Nth ancestor if N is too high' '
test_must_fail git rev-parse HEAD~100000000000000000000000000000000
'