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patch 9.0.2114: overflow detection not accurate when adding digits

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Problem:  overflow detection not accurate when adding digits
Solution: Use a helper function

Use a helper function to better detect overflows before adding integer
digits to a long or an integer variable respectively. Signal the
overflow to the caller function.

closes: #13539

Signed-off-by: Christian Brabandt <cb@256bit.org>
Signed-off-by: Michael Henry <vim@drmikehenry.com>
Signed-off-by: Ernie Rael <errael@raelity.com>
This commit is contained in:
Christian Brabandt
2023-11-19 10:47:21 +01:00
parent 22a97fc241
commit 22cbc8a4e1
4 changed files with 28 additions and 4 deletions
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25
src/misc1.c
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@@ -975,9 +975,8 @@ get_number(
c = safe_vgetc();
if (VIM_ISDIGIT(c))
{
if (n > INT_MAX / 10)
if (vim_append_digit_int(&n, c - '0') == FAIL)
return 0;
n = n * 10 + c - '0';
msg_putchar(c);
++typed;
}
@@ -2817,3 +2816,25 @@ may_trigger_modechanged(void)
restore_v_event(v_event, &save_v_event);
#endif
}
// For overflow detection, add a digit safely to an int value.
int
vim_append_digit_int(int *value, int digit)
{
int x = *value;
if (x > ((INT_MAX - digit) / 10))
return FAIL;
*value = x * 10 + digit;
return OK;
}
// For overflow detection, add a digit safely to a long value.
int
vim_append_digit_long(long *value, int digit)
{
long x = *value;
if (x > ((LONG_MAX - (long)digit) / 10))
return FAIL;
*value = x * 10 + (long)digit;
return OK;
}