2021-11-30 11:09:00

by Zhou Qingyang

Subject: [PATCH] clk: mediatek: net: qlogic: qlcnic: Fix a NULL pointer dereference in qlcnic_83xx_add_rings()

In qlcnic_83xx_add_rings(), the indirect function of
ahw->hw_ops->alloc_mbx_args will be called to allocate memory for
cmd.req.arg, and there is a dereference of it in qlcnic_83xx_add_rings(),
which could lead to a NULL pointer dereference on failure of the
indirect function like qlcnic_83xx_alloc_mbx_args().

Fix this bug by adding a check of alloc_mbx_args(), this patch
imitates the logic of mbx_cmd()'s failure handling.

This bug was found by a static analyzer. The analysis employs
differential checking to identify inconsistent security operations
(e.g., checks or kfrees) between two code paths and confirms that the
inconsistent operations are not recovered in the current function or
the callers, so they constitute bugs.

Note that, as a bug found by static analysis, it can be a false
positive or hard to trigger. Multiple researchers have cross-reviewed
the bug.

Builds with CONFIG_QLCNIC=m show no new warnings, and our
static analyzer no longer warns about this code.

Fixes: 7f9664525f9c ("qlcnic: 83xx memory map and HW access routine")
Signed-off-by: Zhou Qingyang <[email protected]>
---
drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
index d51bac7ba5af..bd0607680329 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
@@ -1077,8 +1077,14 @@ static int qlcnic_83xx_add_rings(struct qlcnic_adapter *adapter)
sds_mbx_size = sizeof(struct qlcnic_sds_mbx);
context_id = recv_ctx->context_id;
num_sds = adapter->drv_sds_rings - QLCNIC_MAX_SDS_RINGS;
- ahw->hw_ops->alloc_mbx_args(&cmd, adapter,
- QLCNIC_CMD_ADD_RCV_RINGS);
+ err = ahw->hw_ops->alloc_mbx_args(&cmd, adapter,
+ QLCNIC_CMD_ADD_RCV_RINGS);
+ if (err) {
+ dev_err(&adapter->pdev->dev,
+ "Failed to alloc mbx args %d\n", err);
+ return err;
+ }
+
cmd.req.arg[1] = 0 | (num_sds << 8) | (context_id << 16);

/* set up status rings, mbx 2-81 */
--
2.25.1

2021-12-02 03:01:55

by patchwork-bot+netdevbpf

Subject: Re: [PATCH] clk: mediatek: net: qlogic: qlcnic: Fix a NULL pointer dereference in qlcnic_83xx_add_rings()

Hello:

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

On Tue, 30 Nov 2021 19:08:48 +0800 you wrote:
> In qlcnic_83xx_add_rings(), the indirect function of
> ahw->hw_ops->alloc_mbx_args will be called to allocate memory for
> cmd.req.arg, and there is a dereference of it in qlcnic_83xx_add_rings(),
> which could lead to a NULL pointer dereference on failure of the
> indirect function like qlcnic_83xx_alloc_mbx_args().
>
> Fix this bug by adding a check of alloc_mbx_args(), this patch
> imitates the logic of mbx_cmd()'s failure handling.
>
> [...]

Here is the summary with links:
- clk: mediatek: net: qlogic: qlcnic: Fix a NULL pointer dereference in qlcnic_83xx_add_rings()
https://git.kernel.org/netdev/net/c/e2dabc4f7e7b

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html