[email protected] wrote:
On Thu, Sep 01, 2005 at 11:41:42AM -0500, Corey Minyard wrote:
Indeed, this function is badly written. In rewriting, I couldn't find a
nice function for reading integers from userspace, and the proc_dointvec
stuff didn't seem terribly suitable. So I wrote my own general
function, which I can move someplace else if someone likes. Patch is
attached. It should not affect correct usage of this file.
Eeeek... Much, _much_ simpler approach would be to have
char buf[10];
if (count > 9)
return -EINVAL;
if (copy_from_user(buf, buffer, count))
return -EFAULT;
buf[count] = '\0';
/* use sscanf() or anything normal */
Would that change behaviour in any cases you care about?
Because then, for a general solution that avoids integer
perversion, you need something like:
char buf[10];
char *end;
if (count > (sizeof(buf) - 1))
return -EINVAL;
if (copy_from_user(buf, buffer, count))
return -EFAULT;
buf[count] = '\0';
newval = simple_strtoul(buf, &end, 0);
if (buf == end)
/* Empty string or first char not a number */
return -EINVAL;
if (*end && ! isspace(*end))
/* Bogus number. */
return -EINVAL;
To me, It's a lot nicer to do:
rv = user_strtoul(....);
if (rv < 0)
return rv;
Plus the scanning function I wrote handles arbitrary leading and
trailing space, etc. Not a big deal, but a little nicer.
-Corey
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