2022-12-22 12:19:27

by Daniil Tatianin

Subject: [PATCH net v3] qlcnic: prevent ->dcb use-after-free on qlcnic_dcb_enable() failure

adapter->dcb would get silently freed inside qlcnic_dcb_enable() in
case qlcnic_dcb_attach() would return an error, which always happens
under OOM conditions. This would lead to use-after-free because both
of the existing callers invoke qlcnic_dcb_get_info() on the obtained
pointer, which is potentially freed at that point.

Propagate errors from qlcnic_dcb_enable(), and instead free the dcb
pointer at callsite using qlcnic_dcb_free(). This also removes the now
unused qlcnic_clear_dcb_ops() helper, which was a simple wrapper around
kfree() also causing memory leaks for partially initialized dcb.

Found by Linux Verification Center (linuxtesting.org) with the SVACE
static analysis tool.

Fixes: 3c44bba1d270 ("qlcnic: Disable DCB operations from SR-IOV VFs")
Reviewed-by: Michal Swiatkowski <[email protected]>
Signed-off-by: Daniil Tatianin <[email protected]>
---
Changes since v1:
- Add a fixes tag + net as a target
- Remove qlcnic_clear_dcb_ops entirely & use qlcnic_dcb_free instead

Changes since v2:
- Don't set ->dcb to NULL explicitly since it's already done by
qlcnic_dcb_free() for us
---
drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c | 8 +++++++-
drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h | 10 ++--------
drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c | 8 +++++++-
3 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c
index dbb800769cb6..c95d56e56c59 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c
@@ -2505,7 +2505,13 @@ int qlcnic_83xx_init(struct qlcnic_adapter *adapter)
goto disable_mbx_intr;

qlcnic_83xx_clear_function_resources(adapter);
- qlcnic_dcb_enable(adapter->dcb);
+
+ err = qlcnic_dcb_enable(adapter->dcb);
+ if (err) {
+ qlcnic_dcb_free(adapter->dcb);
+ goto disable_mbx_intr;
+ }
+
qlcnic_83xx_initialize_nic(adapter, 1);
qlcnic_dcb_get_info(adapter->dcb);

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h
index 7519773eaca6..22afa2be85fd 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h
@@ -41,11 +41,6 @@ struct qlcnic_dcb {
unsigned long state;
};

-static inline void qlcnic_clear_dcb_ops(struct qlcnic_dcb *dcb)
-{
- kfree(dcb);
-}
-
static inline int qlcnic_dcb_get_hw_capability(struct qlcnic_dcb *dcb)
{
if (dcb && dcb->ops->get_hw_capability)
@@ -112,9 +107,8 @@ static inline void qlcnic_dcb_init_dcbnl_ops(struct qlcnic_dcb *dcb)
dcb->ops->init_dcbnl_ops(dcb);
}

-static inline void qlcnic_dcb_enable(struct qlcnic_dcb *dcb)
+static inline int qlcnic_dcb_enable(struct qlcnic_dcb *dcb)
{
- if (dcb && qlcnic_dcb_attach(dcb))
- qlcnic_clear_dcb_ops(dcb);
+ return dcb ? qlcnic_dcb_attach(dcb) : 0;
}
#endif
diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
index 28476b982bab..44dac3c0908e 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
@@ -2599,7 +2599,13 @@ qlcnic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
"Device does not support MSI interrupts\n");

if (qlcnic_82xx_check(adapter)) {
- qlcnic_dcb_enable(adapter->dcb);
+ err = qlcnic_dcb_enable(adapter->dcb);
+ if (err) {
+ qlcnic_dcb_free(adapter->dcb);
+ dev_err(&pdev->dev, "Failed to enable DCB\n");
+ goto err_out_free_hw;
+ }
+
qlcnic_dcb_get_info(adapter->dcb);
err = qlcnic_setup_intr(adapter);

--
2.25.1

2022-12-26 09:39:13

by patchwork-bot+netdevbpf

Subject: Re: [PATCH net v3] qlcnic: prevent ->dcb use-after-free on qlcnic_dcb_enable() failure

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <[email protected]>:

On Thu, 22 Dec 2022 14:52:28 +0300 you wrote:
> adapter->dcb would get silently freed inside qlcnic_dcb_enable() in
> case qlcnic_dcb_attach() would return an error, which always happens
> under OOM conditions. This would lead to use-after-free because both
> of the existing callers invoke qlcnic_dcb_get_info() on the obtained
> pointer, which is potentially freed at that point.
>
> Propagate errors from qlcnic_dcb_enable(), and instead free the dcb
> pointer at callsite using qlcnic_dcb_free(). This also removes the now
> unused qlcnic_clear_dcb_ops() helper, which was a simple wrapper around
> kfree() also causing memory leaks for partially initialized dcb.
>
> [...]

Here is the summary with links:
- [net,v3] qlcnic: prevent ->dcb use-after-free on qlcnic_dcb_enable() failure
https://git.kernel.org/netdev/net/c/13a7c8964afc

You are awesome, thank you!
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