| Message ID | fd4cd8503316d536e1a84fa2ae5bdefdd4b24afe.1697059539.git.gustavoars@kernel.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 65f9e1becb5592c120c9f11adce97f5ca31dce9b |
| Headers | show |
| Series | Fix undefined behavior bug and add bounds-checking coverage | expand |
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
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,
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(-)