6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Gustavo A. R. Silva gustavoars@kernel.org
commit d761bb01c85b22d5b44abe283eb89019693f6595 upstream.
`struct clk_hw_onecell_data` is a flexible structure, which means that it contains flexible-array member at the bottom, in this case array `hws`:
include/linux/clk-provider.h: 1380 struct clk_hw_onecell_data { 1381 unsigned int num; 1382 struct clk_hw *hws[] __counted_by(num); 1383 };
This could potentially lead to an overwrite of the objects following `clk_data` in `struct stratix10_clock_data`, in this case `void __iomem *base;` at run-time:
drivers/clk/socfpga/stratix10-clk.h: 9 struct stratix10_clock_data { 10 struct clk_hw_onecell_data clk_data; 11 void __iomem *base; 12 };
There are currently three different places where memory is allocated for `struct stratix10_clock_data`, including the flex-array `hws` in `struct clk_hw_onecell_data`:
drivers/clk/socfpga/clk-agilex.c: 469 clk_data = devm_kzalloc(dev, struct_size(clk_data, clk_data.hws, 470 num_clks), GFP_KERNEL);
drivers/clk/socfpga/clk-agilex.c: 509 clk_data = devm_kzalloc(dev, struct_size(clk_data, clk_data.hws, 510 num_clks), GFP_KERNEL);
drivers/clk/socfpga/clk-s10.c: 400 clk_data = devm_kzalloc(dev, struct_size(clk_data, clk_data.hws, 401 num_clks), GFP_KERNEL);
I'll use just one of them to describe the issue. See below.
Notice that a total of 440 bytes are allocated for flexible-array member `hws` at line 469:
include/dt-bindings/clock/agilex-clock.h: 70 #define AGILEX_NUM_CLKS 55
drivers/clk/socfpga/clk-agilex.c: 459 struct stratix10_clock_data *clk_data; 460 void __iomem *base; ... 466 467 num_clks = AGILEX_NUM_CLKS; 468 469 clk_data = devm_kzalloc(dev, struct_size(clk_data, clk_data.hws, 470 num_clks), GFP_KERNEL);
`struct_size(clk_data, clk_data.hws, num_clks)` above translates to sizeof(struct stratix10_clock_data) + sizeof(struct clk_hw *) * 55 == 16 + 8 * 55 == 16 + 440 ^^^ | allocated bytes for flex-array `hws`
474 for (i = 0; i < num_clks; i++) 475 clk_data->clk_data.hws[i] = ERR_PTR(-ENOENT); 476 477 clk_data->base = base;
and then some data is written into both `hws` and `base` objects.
Fix this by placing the declaration of object `clk_data` at the end of `struct stratix10_clock_data`. Also, add a comment to make it clear that this object must always be last in the structure.
-Wflex-array-member-not-at-end is coming in GCC-14, and we are getting ready to enable it globally.
Fixes: ba7e258425ac ("clk: socfpga: Convert to s10/agilex/n5x to use clk_hw") Cc: stable@vger.kernel.org Reviewed-by: Kees Cook keescook@chromium.org Signed-off-by: Gustavo A. R. Silva gustavoars@kernel.org Link: https://lore.kernel.org/r/1da736106d8e0806aeafa6e471a13ced490eae22.169811781... Signed-off-by: Stephen Boyd sboyd@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/clk/socfpga/stratix10-clk.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/clk/socfpga/stratix10-clk.h +++ b/drivers/clk/socfpga/stratix10-clk.h @@ -7,8 +7,10 @@ #define __STRATIX10_CLK_H
struct stratix10_clock_data { - struct clk_hw_onecell_data clk_data; void __iomem *base; + + /* Must be last */ + struct clk_hw_onecell_data clk_data; };
struct stratix10_pll_clock {