* [PATCH v4 1/2] Revert "net: mdiobus: Fix memory leak in __mdiobus_register"
@ 2021-09-30 17:49 Pavel Skripkin
2021-09-30 17:50 ` [PATCH v4 2/2] phy: mdio: fix memory leak Pavel Skripkin
2021-10-01 0:40 ` [PATCH v4 1/2] Revert "net: mdiobus: Fix memory leak in __mdiobus_register" patchwork-bot+netdevbpf
0 siblings, 2 replies; 3+ messages in thread
From: Pavel Skripkin @ 2021-09-30 17:49 UTC (permalink / raw)
To: andrew, hkallweit1, linux, davem, kuba, buytenh, afleming
Cc: netdev, linux-kernel, Pavel Skripkin, Yanfei Xu
This reverts commit ab609f25d19858513919369ff3d9a63c02cd9e2e.
This patch is correct in the sense that we _should_ call device_put() in
case of device_register() failure, but the problem in this code is more
vast.
We need to set bus->state to UNMDIOBUS_REGISTERED before calling
device_register() to correctly release the device in mdiobus_free().
This patch prevents us from doing it, since in case of device_register()
failure put_device() will be called 2 times and it will cause UAF or
something else.
Also, Reported-by: tag in revered commit was wrong, since syzbot
reported different leak in same function.
Link: https://lore.kernel.org/netdev/20210928092657.GI2048@kadam/
Acked-by: Yanfei Xu <yanfei.xu@windriver.com>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
Chnages in v4:
No changes
Changes in v3:
CC Yanfei -> Acked-by Yanfei
Changes in v2:
Added this revert
---
drivers/net/phy/mdio_bus.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 6f4b4e5df639..53f034fc2ef7 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -537,7 +537,6 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner)
err = device_register(&bus->dev);
if (err) {
pr_err("mii_bus %s failed to register\n", bus->id);
- put_device(&bus->dev);
return -EINVAL;
}
--
2.33.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH v4 2/2] phy: mdio: fix memory leak
2021-09-30 17:49 [PATCH v4 1/2] Revert "net: mdiobus: Fix memory leak in __mdiobus_register" Pavel Skripkin
@ 2021-09-30 17:50 ` Pavel Skripkin
2021-10-01 0:40 ` [PATCH v4 1/2] Revert "net: mdiobus: Fix memory leak in __mdiobus_register" patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: Pavel Skripkin @ 2021-09-30 17:50 UTC (permalink / raw)
To: andrew, hkallweit1, linux, davem, kuba, buytenh, afleming
Cc: netdev, linux-kernel, Pavel Skripkin,
syzbot+398e7dc692ddbbb4cfec, Dan Carpenter
Syzbot reported memory leak in MDIO bus interface, the problem was in
wrong state logic.
MDIOBUS_ALLOCATED indicates 2 states:
1. Bus is only allocated
2. Bus allocated and __mdiobus_register() fails, but
device_register() was called
In case of device_register() has been called we should call put_device()
to correctly free the memory allocated for this device, but mdiobus_free()
calls just kfree(dev) in case of MDIOBUS_ALLOCATED state
To avoid this behaviour we need to set bus->state to MDIOBUS_UNREGISTERED
_before_ calling device_register(), because put_device() should be
called even in case of device_register() failure.
Link: https://lore.kernel.org/netdev/YVMRWNDZDUOvQjHL@shell.armlinux.org.uk/
Fixes: 46abc02175b3 ("phylib: give mdio buses a device tree presence")
Reported-and-tested-by: syzbot+398e7dc692ddbbb4cfec@syzkaller.appspotmail.com
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
Changes in v4:
Fixed typo in comment, thanks to Wong Vee Khee
Changes in v3:
s/==/=/
Added Dan's Reviewed-by tag
Changes in v2:
Removed new state, since MDIOBUS_UNREGISTERED can be used. Also, moved
bus->state initialization _before_ device_register() call, because
Yanfei's patch is reverted in [v2 1/2]
---
drivers/net/phy/mdio_bus.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 53f034fc2ef7..fca8e335d750 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -534,6 +534,13 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner)
bus->dev.groups = NULL;
dev_set_name(&bus->dev, "%s", bus->id);
+ /* We need to set state to MDIOBUS_UNREGISTERED to correctly release
+ * the device in mdiobus_free()
+ *
+ * State will be updated later in this function in case of success
+ */
+ bus->state = MDIOBUS_UNREGISTERED;
+
err = device_register(&bus->dev);
if (err) {
pr_err("mii_bus %s failed to register\n", bus->id);
--
2.33.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v4 1/2] Revert "net: mdiobus: Fix memory leak in __mdiobus_register"
2021-09-30 17:49 [PATCH v4 1/2] Revert "net: mdiobus: Fix memory leak in __mdiobus_register" Pavel Skripkin
2021-09-30 17:50 ` [PATCH v4 2/2] phy: mdio: fix memory leak Pavel Skripkin
@ 2021-10-01 0:40 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: patchwork-bot+netdevbpf @ 2021-10-01 0:40 UTC (permalink / raw)
To: Pavel Skripkin
Cc: andrew, hkallweit1, linux, davem, kuba, buytenh, afleming,
netdev, linux-kernel, yanfei.xu
Hello:
This series was applied to netdev/net.git (refs/heads/master):
On Thu, 30 Sep 2021 20:49:42 +0300 you wrote:
> This reverts commit ab609f25d19858513919369ff3d9a63c02cd9e2e.
>
> This patch is correct in the sense that we _should_ call device_put() in
> case of device_register() failure, but the problem in this code is more
> vast.
>
> We need to set bus->state to UNMDIOBUS_REGISTERED before calling
> device_register() to correctly release the device in mdiobus_free().
> This patch prevents us from doing it, since in case of device_register()
> failure put_device() will be called 2 times and it will cause UAF or
> something else.
>
> [...]
Here is the summary with links:
- [v4,1/2] Revert "net: mdiobus: Fix memory leak in __mdiobus_register"
https://git.kernel.org/netdev/net/c/10eff1f5788b
- [v4,2/2] phy: mdio: fix memory leak
https://git.kernel.org/netdev/net/c/ca6e11c337da
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-09-30 17:50 ` [PATCH v4 2/2] phy: mdio: fix memory leak Pavel Skripkin
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