On 12/6/18 4:18 PM, Eric Blake wrote:
> POSIX states that the value of endptr is unspecified if strtol()
> fails with EINVAL due to an invalid base argument. Since none of
> the callers to check_strtox_error() initialized endptr, we could
> end up propagating uninitialized data back to a caller on error.
> However, passing an out-of-range base is already a sign of poor
> programming, so let's just assert that base is in range, at which
> point check_strtox_error() can be tightened to assert that it is
> receiving an initialized ep that points somewhere within the
> caller's original string, regardless of whether strto*() succeeded
> or failed with ERANGE.
>
> Reported-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
> Signed-off-by: Eric Blake <ebl...@redhat.com>
> ---
>
> Also tested that this does not negatively impact David's pending
> additions of qemu_strtod{,_finite}(). Thus:
> Based-on: <20181121164421.20780-1-da...@redhat.com>
>
> util/cutils.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/util/cutils.c b/util/cutils.c
> index 91930d1bbeb..e098debdc0c 100644
> --- a/util/cutils.c
> +++ b/util/cutils.c
> @@ -278,6 +278,7 @@ int qemu_strtosz_metric(const char *nptr, const char
> **end, uint64_t *result)
> static int check_strtox_error(const char *nptr, char *ep,
> const char **endptr, int libc_errno)
> {
> + assert(ep >= nptr);
> if (endptr) {
> *endptr = ep;
> }
> @@ -325,6 +326,7 @@ int qemu_strtoi(const char *nptr, const char **endptr,
> int base,
> char *ep;
> long long lresult;
>
> + assert((unsigned) base <= 36 && base != 1);
> if (!nptr) {
> if (endptr) {
> *endptr = nptr;
> @@ -377,6 +379,7 @@ int qemu_strtoui(const char *nptr, const char **endptr,
> int base,
> char *ep;
> long long lresult;
>
> + assert((unsigned) base <= 36 && base != 1);
> if (!nptr) {
> if (endptr) {
> *endptr = nptr;
> @@ -433,6 +436,7 @@ int qemu_strtol(const char *nptr, const char **endptr,
> int base,
> {
> char *ep;
>
> + assert((unsigned) base <= 36 && base != 1);
> if (!nptr) {
> if (endptr) {
> *endptr = nptr;
> @@ -475,6 +479,7 @@ int qemu_strtoul(const char *nptr, const char **endptr,
> int base,
> {
> char *ep;
>
> + assert((unsigned) base <= 36 && base != 1);
> if (!nptr) {
> if (endptr) {
> *endptr = nptr;
> @@ -502,6 +507,7 @@ int qemu_strtoi64(const char *nptr, const char **endptr,
> int base,
> {
> char *ep;
>
> + assert((unsigned) base <= 36 && base != 1);
> if (!nptr) {
> if (endptr) {
> *endptr = nptr;
> @@ -525,6 +531,7 @@ int qemu_strtou64(const char *nptr, const char **endptr,
> int base,
> {
> char *ep;
>
> + assert((unsigned) base <= 36 && base != 1);
> if (!nptr) {
> if (endptr) {
> *endptr = nptr;
> @@ -657,6 +664,7 @@ int parse_uint(const char *s, unsigned long long *value,
> char **endptr,
> char *endp = (char *)s;
> unsigned long long val = 0;
>
> + assert((unsigned) base <= 36 && base != 1);
> if (!s) {
> r = -EINVAL;
> goto out;
>
Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com>
