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[Qemu-trivial] [PATCH] cutils: Assert in-range base for string-to-intege
From: |
Eric Blake |
Subject: |
[Qemu-trivial] [PATCH] cutils: Assert in-range base for string-to-integer conversions |
Date: |
Thu, 6 Dec 2018 09:18:56 -0600 |
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 <address@hidden>
Signed-off-by: Eric Blake <address@hidden>
---
Also tested that this does not negatively impact David's pending
additions of qemu_strtod{,_finite}(). Thus:
Based-on: <address@hidden>
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;
--
2.17.2
- [Qemu-trivial] [PATCH] cutils: Assert in-range base for string-to-integer conversions,
Eric Blake <=