CVE-2018-19591: if_nametoindex: Fix descriptor for overlong name [BZ #23927]
Commit Message
* Andreas Schwab:
> On Nov 27 2018, Florian Weimer <fweimer@redhat.com> wrote:
>
>> diff --git a/sysdeps/unix/sysv/linux/if_index.c b/sysdeps/unix/sysv/linux/if_index.c
>> index e3d08982d9..3e999d6509 100644
>> --- a/sysdeps/unix/sysv/linux/if_index.c
>> +++ b/sysdeps/unix/sysv/linux/if_index.c
>> @@ -45,6 +45,7 @@ __if_nametoindex (const char *ifname)
>>
>> if (strlen (ifname) >= IFNAMSIZ)
>> {
>> + __close_nocancel_nostatus (fd);
>> __set_errno (ENODEV);
>> return 0;
>> }
>
> Just move it before the opensock call.
Like this?
2018-11-27 Florian Weimer <fweimer@redhat.com>
[BZ #23927]
CVE-2018-19591
* sysdeps/unix/sysv/linux/if_index.c (__if_nametoindex): Avoid
descriptor leak in case of ENODEV error.
Comments
On Tue, Nov 27, 2018 at 9:13 AM Florian Weimer <fweimer@redhat.com> wrote:
>
> * Andreas Schwab:
>
> > On Nov 27 2018, Florian Weimer <fweimer@redhat.com> wrote:
> >
> >> diff --git a/sysdeps/unix/sysv/linux/if_index.c b/sysdeps/unix/sysv/linux/if_index.c
> >> index e3d08982d9..3e999d6509 100644
> >> --- a/sysdeps/unix/sysv/linux/if_index.c
> >> +++ b/sysdeps/unix/sysv/linux/if_index.c
> >> @@ -45,6 +45,7 @@ __if_nametoindex (const char *ifname)
> >>
> >> if (strlen (ifname) >= IFNAMSIZ)
> >> {
> >> + __close_nocancel_nostatus (fd);
> >> __set_errno (ENODEV);
> >> return 0;
> >> }
> >
> > Just move it before the opensock call.
>
> Like this?
>
> 2018-11-27 Florian Weimer <fweimer@redhat.com>
>
> [BZ #23927]
> CVE-2018-19591
> * sysdeps/unix/sysv/linux/if_index.c (__if_nametoindex): Avoid
> descriptor leak in case of ENODEV error.
>
> diff --git a/NEWS b/NEWS
> index f488821af1..1098be1afb 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -57,7 +57,9 @@ Changes to build and runtime requirements:
>
> Security related changes:
>
> - [Add security related changes here]
> + CVE-2018-19591: A file descriptor leak in if_nametoindex can lead to a
> + denial of service due to resource exhaustion when processing getaddrinfo
> + calls with crafted host names. Reported by Guido Vranken.
>
> The following bugs are resolved with this release:
>
> diff --git a/sysdeps/unix/sysv/linux/if_index.c b/sysdeps/unix/sysv/linux/if_index.c
> index e3d08982d9..782fc5e175 100644
> --- a/sysdeps/unix/sysv/linux/if_index.c
> +++ b/sysdeps/unix/sysv/linux/if_index.c
> @@ -38,11 +38,6 @@ __if_nametoindex (const char *ifname)
> return 0;
> #else
> struct ifreq ifr;
> - int fd = __opensock ();
> -
> - if (fd < 0)
> - return 0;
> -
> if (strlen (ifname) >= IFNAMSIZ)
> {
> __set_errno (ENODEV);
> @@ -50,6 +45,12 @@ __if_nametoindex (const char *ifname)
> }
>
> strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));
> +
> + int fd = __opensock ();
> +
> + if (fd < 0)
> + return 0;
> +
> if (__ioctl (fd, SIOCGIFINDEX, &ifr) < 0)
> {
> int saved_errno = errno;
Thanks for the fix, is this going to be in master?
Can we take this patch as CVE fix?
* Victor Rodriguez:
> Thanks for the fix, is this going to be in master?
> Can we take this patch as CVE fix?
I've pushed this to master now. There's going to be test cases later.
Thanks,
Florian
@@ -57,7 +57,9 @@ Changes to build and runtime requirements:
Security related changes:
- [Add security related changes here]
+ CVE-2018-19591: A file descriptor leak in if_nametoindex can lead to a
+ denial of service due to resource exhaustion when processing getaddrinfo
+ calls with crafted host names. Reported by Guido Vranken.
The following bugs are resolved with this release:
@@ -38,11 +38,6 @@ __if_nametoindex (const char *ifname)
return 0;
#else
struct ifreq ifr;
- int fd = __opensock ();
-
- if (fd < 0)
- return 0;
-
if (strlen (ifname) >= IFNAMSIZ)
{
__set_errno (ENODEV);
@@ -50,6 +45,12 @@ __if_nametoindex (const char *ifname)
}
strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));
+
+ int fd = __opensock ();
+
+ if (fd < 0)
+ return 0;
+
if (__ioctl (fd, SIOCGIFINDEX, &ifr) < 0)
{
int saved_errno = errno;