Commit 53a90b97 authored by Eric Blake's avatar Eric Blake Committed by Laurent Vivier
Browse files

cutils: Assert in-range base for string-to-integer conversions 



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: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarMarkus Armbruster <armbru@redhat.com>
Reviewed-by: default avatarPhilippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20181206151856.77503-1-eblake@redhat.com>
Signed-off-by: default avatarLaurent Vivier <laurent@vivier.eu>
parent 9e722ebc

util/cutils.c

+8 −0
Original line number Diff line number Diff line
@@ -280,6 +280,7 @@ int qemu_strtosz_metric(const char *nptr, 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;

    }
@@ -327,6 +328,7 @@ 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;
@@ -379,6 +381,7 @@ 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;
@@ -435,6 +438,7 @@ 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;
@@ -477,6 +481,7 @@ 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;
@@ -504,6 +509,7 @@ 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;
@@ -527,6 +533,7 @@ 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;
@@ -594,6 +601,7 @@ 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;