Re: [patch] RDS: fix an integer overflow check
flat view
From: Jeff Liu <hidden>
Date: 2012-10-13 13:25:58
Also in:
kernel-janitors
On 10/12/2012 03:31 PM, Dan Carpenter wrote:
quoted hunk ↗ jump to hunk
"len" is an int. We verified that len was postive already. Since PAGE_SIZE is specified as an unsigned long, the type it promoted to unsigned and the condition is never true. I'm not sure this check is actually needed. It might be that we could just remove it? Signed-off-by: Dan Carpenter <redacted>diff --git a/net/rds/info.c b/net/rds/info.c index 9a6b4f6..4d62618 100644 --- a/net/rds/info.c +++ b/net/rds/info.c@@ -176,7 +176,7 @@ int rds_info_getsockopt(struct socket *sock, int optname, char __user *optval, /* check for all kinds of wrapping and the like */ start = (unsigned long)optval; - if (len < 0 || len + PAGE_SIZE - 1 < len || start + len < start) {
Looks the original thought is to check up len + (PAGE_SIZE - 1) < len to avoid integer overflow, but lack of a "()".
However, we only have one add operation in this function which were shown as following:
nr_pages = (PAGE_ALIGN(start + len) - (start & PAGE_MASK))
>> PAGE_SHIFT;
I also gone through the call chains, there is no other (start + len) operations for all transport, I think it's safe to remove this check up if so.
Thanks,
-Jeff+ if (len < 0 || len > INT_MAX - (PAGE_SIZE - 1) || start + len < start) {
ret = -EINVAL;
goto out;
}
--
To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html