[2/2,next] clk: socfpga: agilex: Add bounds-checking coverage for struct stratix10_clock_data
Commit Message
In order to gain the bounds-checking coverage that __counted_by provides
to flexible-array members at run-time via CONFIG_UBSAN_BOUNDS (for array
indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions),
we must make sure that the counter member, in this case `num`, is updated
before the first access to the flex-array member, in this case array `hws`.
commit f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with
__counted_by") introduced `__counted_by` for `struct clk_hw_onecell_data`
together with changes to relocate some of assignments of counter `num`
before `hws` is accessed:
include/linux/clk-provider.h:
1380 struct clk_hw_onecell_data {
1381 unsigned int num;
1382 struct clk_hw *hws[] __counted_by(num);
1383 };
However, this structure is used as a member in other structs, in this
case in `struct sstratix10_clock_data`:
drivers/clk/socfpga/stratix10-clk.h:
9 struct stratix10_clock_data {
10 void __iomem *base;
11
12 /* Must be last */
13 struct clk_hw_onecell_data clk_data;
14 };
Hence, we need to move the assignments to `clk_data->clk_data.num` after
allocations for `struct stratix10_clock_data` and before accessing the
flexible array `clk_data->clk_data.hws`. And, as assignments for both
`clk_data->clk_data.num` and `clk_data->base` are originally adjacent to
each other, relocate both assignments together.
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
drivers/clk/socfpga/clk-agilex.c | 12 ++++++------
drivers/clk/socfpga/clk-s10.c | 6 +++---
2 files changed, 9 insertions(+), 9 deletions(-)
Comments
On Wed, Oct 11, 2023 at 03:35:26PM -0600, Gustavo A. R. Silva wrote:
> In order to gain the bounds-checking coverage that __counted_by provides
> to flexible-array members at run-time via CONFIG_UBSAN_BOUNDS (for array
> indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions),
> we must make sure that the counter member, in this case `num`, is updated
> before the first access to the flex-array member, in this case array `hws`.
>
> commit f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with
> __counted_by") introduced `__counted_by` for `struct clk_hw_onecell_data`
> together with changes to relocate some of assignments of counter `num`
> before `hws` is accessed:
>
> include/linux/clk-provider.h:
> 1380 struct clk_hw_onecell_data {
> 1381 unsigned int num;
> 1382 struct clk_hw *hws[] __counted_by(num);
> 1383 };
>
> However, this structure is used as a member in other structs, in this
> case in `struct sstratix10_clock_data`:
>
> drivers/clk/socfpga/stratix10-clk.h:
> 9 struct stratix10_clock_data {
> 10 void __iomem *base;
> 11
> 12 /* Must be last */
> 13 struct clk_hw_onecell_data clk_data;
> 14 };
>
> Hence, we need to move the assignments to `clk_data->clk_data.num` after
> allocations for `struct stratix10_clock_data` and before accessing the
> flexible array `clk_data->clk_data.hws`. And, as assignments for both
> `clk_data->clk_data.num` and `clk_data->base` are originally adjacent to
> each other, relocate both assignments together.
>
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Yeah, ew. That's super tricky. Nice find.
Reviewed-by: Kees Cook <keescook@chromium.org>
>> Hence, we need to move the assignments to `clk_data->clk_data.num` after
>> allocations for `struct stratix10_clock_data` and before accessing the
>> flexible array `clk_data->clk_data.hws`. And, as assignments for both
>> `clk_data->clk_data.num` and `clk_data->base` are originally adjacent to
>> each other, relocate both assignments together.
>>
>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>
> Yeah, ew. That's super tricky. Nice find.
Indeed. D:
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
Thanks!
--
Gustavo
@@ -471,12 +471,12 @@ static int agilex_clkmgr_init(struct platform_device *pdev)
if (!clk_data)
return -ENOMEM;
+ clk_data->clk_data.num = num_clks;
+ clk_data->base = base;
+
for (i = 0; i < num_clks; i++)
clk_data->clk_data.hws[i] = ERR_PTR(-ENOENT);
- clk_data->base = base;
- clk_data->clk_data.num = num_clks;
-
agilex_clk_register_pll(agilex_pll_clks, ARRAY_SIZE(agilex_pll_clks), clk_data);
agilex_clk_register_c_perip(agilex_main_perip_c_clks,
@@ -511,12 +511,12 @@ static int n5x_clkmgr_init(struct platform_device *pdev)
if (!clk_data)
return -ENOMEM;
- for (i = 0; i < num_clks; i++)
- clk_data->clk_data.hws[i] = ERR_PTR(-ENOENT);
-
clk_data->base = base;
clk_data->clk_data.num = num_clks;
+ for (i = 0; i < num_clks; i++)
+ clk_data->clk_data.hws[i] = ERR_PTR(-ENOENT);
+
n5x_clk_register_pll(agilex_pll_clks, ARRAY_SIZE(agilex_pll_clks), clk_data);
n5x_clk_register_c_perip(n5x_main_perip_c_clks,
@@ -402,12 +402,12 @@ static int s10_clkmgr_init(struct platform_device *pdev)
if (!clk_data)
return -ENOMEM;
- for (i = 0; i < num_clks; i++)
- clk_data->clk_data.hws[i] = ERR_PTR(-ENOENT);
-
clk_data->base = base;
clk_data->clk_data.num = num_clks;
+ for (i = 0; i < num_clks; i++)
+ clk_data->clk_data.hws[i] = ERR_PTR(-ENOENT);
+
s10_clk_register_pll(s10_pll_clks, ARRAY_SIZE(s10_pll_clks), clk_data);
s10_clk_register_c_perip(s10_main_perip_c_clks,