diff mbox series

[v3,2/2,next] clk: socfpga: agilex: Add bounds-checking coverage for struct stratix10_clock_data

Message ID 385c516c498e07eb9a521107e16a7efd26e86ea5.1698117815.git.gustavoars@kernel.org (mailing list archive)
State Mainlined
Commit 65f9e1becb5592c120c9f11adce97f5ca31dce9b
Headers show
Series clk: socfpga: Fix undefined behavior bug and add bounds-checking coverage | expand

Commit Message

Gustavo A. R. Silva Oct. 24, 2023, 3:31 a.m. UTC
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.

Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
Changes in v3:
 - None, really. Just Cc linux-clk@vger.kernel.org this time.

Changes in v2:
 - None.
 - Link: https://lore.kernel.org/linux-hardening/f531ae35ef434b62f48534c67ad3b1013bff0536.1697493574.git.gustavoars@kernel.org/

v1:
 - Link: https://lore.kernel.org/linux-hardening/fd4cd8503316d536e1a84fa2ae5bdefdd4b24afe.1697059539.git.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

Stephen Boyd Oct. 24, 2023, 3:35 a.m. UTC | #1
Quoting Gustavo A. R. Silva (2023-10-23 20:31:42)
> 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.
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---

Applied to clk-next
diff mbox series

Patch

diff --git a/drivers/clk/socfpga/clk-agilex.c b/drivers/clk/socfpga/clk-agilex.c
index 6b65a74aefa6..8dd94f64756b 100644
--- a/drivers/clk/socfpga/clk-agilex.c
+++ b/drivers/clk/socfpga/clk-agilex.c
@@ -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,
diff --git a/drivers/clk/socfpga/clk-s10.c b/drivers/clk/socfpga/clk-s10.c
index 3752bd9c103c..b4bf4e2d38e1 100644
--- a/drivers/clk/socfpga/clk-s10.c
+++ b/drivers/clk/socfpga/clk-s10.c
@@ -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,