2015-02-16 18:49:26

by Anshul Garg

Subject: [PATCH] lib/kstrtox.c Stop parsing integer on overflow

From: Anshul Garg <[email protected]>

While converting string representation to integer
break the loop if overflow is detected.

Signed-off-by: Anshul Garg <[email protected]>
---
lib/kstrtox.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/kstrtox.c b/lib/kstrtox.c
index ec8da78..6f30209 100644
--- a/lib/kstrtox.c
+++ b/lib/kstrtox.c
@@ -70,8 +70,10 @@ unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long
* it in the max base we support (16)
*/
if (unlikely(res & (~0ull << 60))) {
- if (res > div_u64(ULLONG_MAX - val, base))
+ if (res > div_u64(ULLONG_MAX - val, base)) {
overflow = 1;
+ break;
+ }
}
res = res * base + val;
rv++;
--
1.7.9.5


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2015-02-17 23:20:48

by Richard Weinberger

Subject: Re: [PATCH] lib/kstrtox.c Stop parsing integer on overflow

On Mon, Feb 16, 2015 at 7:48 PM, Anshul Garg <[email protected]> wrote:
> From: Anshul Garg <[email protected]>
>
> While converting string representation to integer
> break the loop if overflow is detected.
>
> Signed-off-by: Anshul Garg <[email protected]>
> ---
> lib/kstrtox.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/lib/kstrtox.c b/lib/kstrtox.c
> index ec8da78..6f30209 100644
> --- a/lib/kstrtox.c
> +++ b/lib/kstrtox.c
> @@ -70,8 +70,10 @@ unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long
> * it in the max base we support (16)
> */
> if (unlikely(res & (~0ull << 60))) {
> - if (res > div_u64(ULLONG_MAX - val, base))
> + if (res > div_u64(ULLONG_MAX - val, base)) {
> overflow = 1;
> + break;

This changes the behaviour as described at the function description.
Did you double check that all users of that function can deal with that?

> + }
> }
> res = res * base + val;
> rv++;
> --
> 1.7.9.5
>
>
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--
Thanks,
//richard