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SubjectRe: [PATCH] staging: lustre: lustre: obdclass: lprocfs_status.c: Fix for possible null pointer dereference
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On Sun, 2014-12-14 at 23:52 +0100, Rickard Strandqvist wrote:
> There is otherwise a risk of a possible null pointer dereference.
>
> Was largely found by using a static code analysis program called cppcheck.

Perhaps the tool could use a little work.
It's not possible for end to be NULL no?

unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
{
unsigned long long result;
unsigned int rv;

cp = _parse_integer_fixup_radix(cp, &base);
rv = _parse_integer(cp, base, &result);
/* FIXME */
cp += (rv & ~KSTRTOX_OVERFLOW);

if (endp)
*endp = (char *)cp;

return result;
}
EXPORT_SYMBOL(simple_strtoull);


> diff --git a/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c b/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c
[]

Above this:

whole = simple_strtoull(pbuf, &end, 10);

> +++ b/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c
> @@ -1897,17 +1897,19 @@ int lprocfs_write_frac_u64_helper(const char *buffer, unsigned long count,
> }
>
> units = 1;
> - switch (*end) {
> - case 'p': case 'P':
> - units <<= 10;
> - case 't': case 'T':
> - units <<= 10;
> - case 'g': case 'G':
> - units <<= 10;
> - case 'm': case 'M':
> - units <<= 10;
> - case 'k': case 'K':
> - units <<= 10;
> + if (end) {
> + switch (*end) {
> + case 'p': case 'P':
> + units <<= 10;
> + case 't': case 'T':
> + units <<= 10;
> + case 'g': case 'G':
> + units <<= 10;
> + case 'm': case 'M':
> + units <<= 10;
> + case 'k': case 'K':
> + units <<= 10;
> + }

The only thing I might do is

switch (tolower(*end)) {

and remove the second case entry for each line



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