CVE-2018-19591: if_nametoindex: Fix descriptor for overlong name [BZ #23927]

Message ID 87a7luh87n.fsf@oldenburg.str.redhat.com
State New
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  • CVE-2018-19591: if_nametoindex: Fix descriptor for overlong name [BZ #23927]
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Commit Message

Florian Weimer Nov. 27, 2018, 3:05 p.m.
We need to check the length of the string right before the strncpy call
to avoid reintroducing the compiler warning from bug 22442.

2018-11-27  Florian Weimer  <fweimer@redhat.com>

	[BZ #23927]
	CVE-2018-19591
	* sysdeps/unix/sysv/linux/if_index.c (__if_nametoindex): Close
	descriptor in case of ENODEV error.

Comments

Andreas Schwab Nov. 27, 2018, 3:08 p.m. | #1
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.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
Florian Weimer Nov. 27, 2018, 3:13 p.m. | #2
* 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;
Andreas Schwab Nov. 27, 2018, 3:52 p.m. | #3
Ok.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
Victor Rodriguez Nov. 27, 2018, 5:10 p.m. | #4
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?
Florian Weimer Nov. 27, 2018, 5:13 p.m. | #5
* 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

Patch

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..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;
     }