From 033998c21f01e7b7d91e4aa51a358f8016f3740a Mon Sep 17 00:00:00 2001

From: Viktor Mihajlovski <mihajlov@linux.ibm.com>

Date: Tue, 27 Apr 2021 15:25:16 +0200

Subject: [PATCH] udev: allow onboard index up to 65535

The maximum allowed value of the sysfs device index entry was limited to

16383 (2^14-1) to avoid the generation of unreasonable onboard interface

names.

For s390 the index can assume a value of up to 65535 (2^16-1) which is

now allowed depending on the new naming flag NAMING_16BIT_INDEX.

Larger index values are considered unreasonable and remain to be

ignored.

Related: #1939914

(cherry picked from commit 5a7eb46c0206411d380543021291b4bca0b6f59f)

---

 man/systemd.net-naming-scheme.xml |  7 ++++++-

 src/udev/udev-builtin-net_id.c    | 22 +++++++++++++++-------

 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/man/systemd.net-naming-scheme.xml b/man/systemd.net-naming-scheme.xml

index e42c93eaad..a567483995 100644

--- a/man/systemd.net-naming-scheme.xml

+++ b/man/systemd.net-naming-scheme.xml

@@ -320,7 +320,12 @@

           of the <filename>function_id</filename> device attribute. This attribute is now used to build the

           <varname>ID_NET_NAME_SLOT</varname>. Before that, all slot names were parsed as decimal

           numbers, which could either result in an incorrect value of the <varname>ID_NET_NAME_SLOT</varname>

-          property or none at all.</para></listitem>

+          property or none at all.</para>

+

+          <para>Some firmware and hypervisor implementations report unreasonable high numbers for the onboard

+          index. To prevent the generation of bogus onbard interface names, index numbers greater than 16381

+          (2^14-1) were ignored. For s390 PCI devices index values up to 65535 (2^16-1) are valid. To account

+          for that, the limit is increased to now 65535.</para></listitem>

         </varlistentry>

         <para>Note that <constant>latest</constant> may be used to denote the latest scheme known to this

diff --git a/src/udev/udev-builtin-net_id.c b/src/udev/udev-builtin-net_id.c

index ba7638fcb8..df84acf27c 100644

--- a/src/udev/udev-builtin-net_id.c

+++ b/src/udev/udev-builtin-net_id.c

@@ -104,7 +104,8 @@

 #include "udev.h"

 #include "udev-util.h"

-#define ONBOARD_INDEX_MAX (16*1024-1)

+#define ONBOARD_14BIT_INDEX_MAX ((1U << 14) - 1)

+#define ONBOARD_16BIT_INDEX_MAX ((1U << 16) - 1)

 /* So here's the deal: net_id is supposed to be an excercise in providing stable names for network devices. However, we

  * also want to keep updating the naming scheme used in future versions of net_id. These two goals of course are

@@ -127,6 +128,7 @@ typedef enum NamingSchemeFlags {

         NAMING_NPAR_ARI        = 1 << 1, /* Use NPAR "ARI", see 6bc04997b6eab35d1cb9fa73889892702c27be09 */

         NAMING_BRIDGE_NO_SLOT  = 1 << 9, /* Don't use PCI hotplug slot information if the corresponding device is a PCI bridge */

         NAMING_SLOT_FUNCTION_ID = 1 << 10, /* Use function_id if present to identify PCI hotplug slots */

+        NAMING_16BIT_INDEX      = 1 << 11, /* Allow full 16-bit for the onboard index */

         /* And now the masks that combine the features above */

         NAMING_V238 = 0,

@@ -138,7 +140,7 @@ typedef enum NamingSchemeFlags {

         NAMING_RHEL_8_4 = NAMING_V239|NAMING_BRIDGE_NO_SLOT,

         NAMING_RHEL_8_5 = NAMING_RHEL_8_4,

         NAMING_RHEL_8_6 = NAMING_RHEL_8_4,

-        NAMING_RHEL_8_7 = NAMING_RHEL_8_4|NAMING_SLOT_FUNCTION_ID,

+        NAMING_RHEL_8_7 = NAMING_RHEL_8_4|NAMING_SLOT_FUNCTION_ID|NAMING_16BIT_INDEX,

         _NAMING_SCHEME_FLAGS_INVALID = -1,

 } NamingSchemeFlags;

@@ -326,6 +328,16 @@ out_unref:

         return r;

 }

+static bool is_valid_onboard_index(unsigned long idx) {

+        /* Some BIOSes report rubbish indexes that are excessively high (2^24-1 is an index VMware likes to

+         * report for example). Let's define a cut-off where we don't consider the index reliable anymore. We

+         * pick some arbitrary cut-off, which is somewhere beyond the realistic number of physical network

+         * interface a system might have. Ideally the kernel would already filter this crap for us, but it

+         * doesn't currently. The initial cut-off value (2^14-1) was too conservative for s390 PCI which

+         * allows for index values up 2^16-1 which is now enabled with the NAMING_16BIT_INDEX naming flag. */

+        return idx <= (naming_scheme_has(NAMING_16BIT_INDEX) ? ONBOARD_16BIT_INDEX_MAX : ONBOARD_14BIT_INDEX_MAX);

+}

+

 /* retrieve on-board index number and label from firmware */

 static int dev_pci_onboard(struct udev_device *dev, struct netnames *names) {

         unsigned dev_port = 0;

@@ -346,11 +358,7 @@ static int dev_pci_onboard(struct udev_device *dev, struct netnames *names) {

         if (idx <= 0)

                 return -EINVAL;

-        /* Some BIOSes report rubbish indexes that are excessively high (2^24-1 is an index VMware likes to report for

-         * example). Let's define a cut-off where we don't consider the index reliable anymore. We pick some arbitrary

-         * cut-off, which is somewhere beyond the realistic number of physical network interface a system might

-         * have. Ideally the kernel would already filter his crap for us, but it doesn't currently. */

-        if (idx > ONBOARD_INDEX_MAX)

+        if (!is_valid_onboard_index(idx))

                 return -ENOENT;

         /* kernel provided port index for multiple ports on a single PCI function */