[PATCH] kernel: fix bugs added with mac-address-ascii support
Rafał Miłecki
zajec5 at gmail.com
Thu Jan 5 04:33:18 PST 2023
From: Rafał Miłecki <rafal at milecki.pl>
1. Check for -EPROBE_DEFER
If it occurs we have to return immediately. Trying other properties
could result in another error and ignoring -EPROBE_DEFER which has a
special meaning.
2. Check for read result
Assuming property->read() success can result in NULL pointer
dereference. It happens e.g. for "mac-address" with NVMEM cell
containing invalid MAC.
3. Simplify code
Don't move cell reading & nvmem_cell_put() into a loop. Simplify loop
code.
Fixes: ecd81de7a5ab ("ath79: add nvmem cell mac-address-ascii support")
Cc: Yousong Zhou <yszhou4tech at gmail.com>
Signed-off-by: Rafał Miłecki <rafal at milecki.pl>
---
...of_net-add-mac-address-ascii-support.patch | 39 +++++++++----------
...of_net-add-mac-address-ascii-support.patch | 39 +++++++++----------
2 files changed, 38 insertions(+), 40 deletions(-)
diff --git a/target/linux/generic/hack-5.10/601-of_net-add-mac-address-ascii-support.patch b/target/linux/generic/hack-5.10/601-of_net-add-mac-address-ascii-support.patch
index 5dd70f5f71..cf2a26c9d6 100644
--- a/target/linux/generic/hack-5.10/601-of_net-add-mac-address-ascii-support.patch
+++ b/target/linux/generic/hack-5.10/601-of_net-add-mac-address-ascii-support.patch
@@ -75,36 +75,35 @@ Submitted-by: Yousong Zhou <yszhou4tech at gmail.com>
/**
* Obtain the MAC address from an nvmem cell named 'mac-address' associated
* with given device.
-@@ -552,19 +609,23 @@ int nvmem_get_mac_address(struct device
+@@ -550,21 +607,28 @@ EXPORT_SYMBOL(eth_platform_get_mac_addre
+ */
+ int nvmem_get_mac_address(struct device *dev, void *addrbuf)
{
++ struct nvmem_cell_mac_address_property *property;
struct nvmem_cell *cell;
const void *mac;
- size_t len;
-+ struct nvmem_cell_mac_address_property *property;
+ int i;
-
-- cell = nvmem_cell_get(dev, "mac-address");
-- if (IS_ERR(cell))
-- return PTR_ERR(cell);
--
-- mac = nvmem_cell_read(cell, &len);
-- nvmem_cell_put(cell);
--
-- if (IS_ERR(mac))
-- return PTR_ERR(mac);
++
+ for (i = 0; i < ARRAY_SIZE(nvmem_cell_mac_address_properties); i++) {
+ property = &nvmem_cell_mac_address_properties[i];
+ cell = nvmem_cell_get(dev, property->name);
-+ if (IS_ERR(cell)) {
-+ if (i == ARRAY_SIZE(nvmem_cell_mac_address_properties) - 1)
-+ return PTR_ERR(cell);
-+ continue;
-+ }
-+ mac = property->read(cell);
-+ nvmem_cell_put(cell);
-+ break;
++ /* For -EPROBE_DEFER don't try other properties. We'll get back to this one. */
++ if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
++ break;
+ }
+- cell = nvmem_cell_get(dev, "mac-address");
+ if (IS_ERR(cell))
+ return PTR_ERR(cell);
+
+- mac = nvmem_cell_read(cell, &len);
++ mac = property->read(cell);
+ nvmem_cell_put(cell);
+-
+ if (IS_ERR(mac))
+ return PTR_ERR(mac);
+
- if (len != ETH_ALEN || !is_valid_ether_addr(mac)) {
+ if (!is_valid_ether_addr(mac)) {
kfree(mac);
diff --git a/target/linux/generic/hack-5.15/601-of_net-add-mac-address-ascii-support.patch b/target/linux/generic/hack-5.15/601-of_net-add-mac-address-ascii-support.patch
index 4ab05b4ea6..eb390961d7 100644
--- a/target/linux/generic/hack-5.15/601-of_net-add-mac-address-ascii-support.patch
+++ b/target/linux/generic/hack-5.15/601-of_net-add-mac-address-ascii-support.patch
@@ -75,36 +75,35 @@ Submitted-by: Yousong Zhou <yszhou4tech at gmail.com>
/**
* nvmem_get_mac_address - Obtain the MAC address from an nvmem cell named
* 'mac-address' associated with given device.
-@@ -551,19 +608,23 @@ int nvmem_get_mac_address(struct device
+@@ -549,21 +606,28 @@ EXPORT_SYMBOL(eth_platform_get_mac_addre
+ */
+ int nvmem_get_mac_address(struct device *dev, void *addrbuf)
{
++ struct nvmem_cell_mac_address_property *property;
struct nvmem_cell *cell;
const void *mac;
- size_t len;
-+ struct nvmem_cell_mac_address_property *property;
+ int i;
-
-- cell = nvmem_cell_get(dev, "mac-address");
-- if (IS_ERR(cell))
-- return PTR_ERR(cell);
--
-- mac = nvmem_cell_read(cell, &len);
-- nvmem_cell_put(cell);
--
-- if (IS_ERR(mac))
-- return PTR_ERR(mac);
++
+ for (i = 0; i < ARRAY_SIZE(nvmem_cell_mac_address_properties); i++) {
+ property = &nvmem_cell_mac_address_properties[i];
+ cell = nvmem_cell_get(dev, property->name);
-+ if (IS_ERR(cell)) {
-+ if (i == ARRAY_SIZE(nvmem_cell_mac_address_properties) - 1)
-+ return PTR_ERR(cell);
-+ continue;
-+ }
-+ mac = property->read(cell);
-+ nvmem_cell_put(cell);
-+ break;
++ /* For -EPROBE_DEFER don't try other properties. We'll get back to this one. */
++ if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
++ break;
+ }
+- cell = nvmem_cell_get(dev, "mac-address");
+ if (IS_ERR(cell))
+ return PTR_ERR(cell);
+
+- mac = nvmem_cell_read(cell, &len);
++ mac = property->read(cell);
+ nvmem_cell_put(cell);
+-
+ if (IS_ERR(mac))
+ return PTR_ERR(mac);
+
- if (len != ETH_ALEN || !is_valid_ether_addr(mac)) {
+ if (!is_valid_ether_addr(mac)) {
kfree(mac);
--
2.34.1
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