CVE-2024-53193

In the Linux kernel, the following vulnerability has been resolved:

clk: clk-loongson2: Fix memory corruption bug in struct loongson2_clk_provider

Some heap space is allocated for the flexible structure struct clk_hw_onecell_data and its flexible-array member hws through the composite structure struct loongson2_clk_provider in function loongson2_clk_probe(), as shown below:

289 struct loongson2_clk_provider *clp; ... 296 for (p = data; p->name; p++) 297 clks_num++; 298 299 clp = devm_kzalloc(dev, struct_size(clp, clk_data.hws, clks_num), 300 GFP_KERNEL);

Then some data is written into the flexible array:

350 clp->clk_data.hws[p->id] = hw;

This corrupts clk_lock, which is the spinlock variable immediately following the clk_data member in struct loongson2_clk_provider:

struct loongson2_clk_provider { void __iomem *base; struct device dev; struct clk_hw_onecell_data clk_data; spinlock_t clk_lock; / protect access to DIV registers */ };

The problem is that the flexible structure is currently placed in the middle of struct loongson2_clk_provider instead of at the end.

Fix this by moving struct clk_hw_onecell_data clk_data; to the end of struct loongson2_clk_provider. Also, add a code comment to help prevent this from happening again in case new members are added to the structure in the future.

This change also fixes the following -Wflex-array-member-not-at-end warning:

drivers/clk/clk-loongson2.c:32:36: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

This vulnerability does not present a security risk to Red Hat Enterprise Linux as the affected hardware architecture and clock provider driver are not supported or enabled in Red Hat product kernels. The flaw is confined to the Loongson-2 platform clock controller code, which was introduced in upstream kernels newer than those utilized in supported enterprise releases. As a result, default configurations across all Red Hat platforms remain unaffected.