Messages in this thread Patch in this message | | | From | Zhou Qingyang <> | Subject | [PATCH] clk: x86: Fix a wild pointer dereference in fch_clk_probe() | Date | Tue, 30 Nov 2021 19:15:17 +0800 |
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In fch_clk_probe(), the return value of clk_hw_register_mux() is assigned to hws[ST_CLK_MUX] and there is a dereference of it in fch_clk_probe(), which could lead to a wild pointer dereference on failure of clk_hw_register_mux().
Fix this bug by adding a check of hws[ST_CLK_MUX].
This bug was found by a static analyzer. The analysis employs differential checking to identify inconsistent security operations (e.g., checks or kfrees) between two code paths and confirms that the inconsistent operations are not recovered in the current function or the callers, so they constitute bugs.
Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Multiple researchers have cross-reviewed the bug.
Builds with CONFIG_X86_AMD_PLATFORM_DEVICE=y show no new warnings, and our static analyzer no longer warns about this code.
Fixes: 19fe87fd854a ("clk: x86: Support RV architecture") Signed-off-by: Zhou Qingyang <zhou1615@umn.edu> --- drivers/clk/x86/clk-fch.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/clk/x86/clk-fch.c b/drivers/clk/x86/clk-fch.c index 8f7c5142b0f0..1539ee59c04a 100644 --- a/drivers/clk/x86/clk-fch.c +++ b/drivers/clk/x86/clk-fch.c @@ -51,6 +51,8 @@ static int fch_clk_probe(struct platform_device *pdev) clk_oscout1_parents, ARRAY_SIZE(clk_oscout1_parents), 0, fch_data->base + CLKDRVSTR2, OSCOUT1CLK25MHZ, 3, 0, NULL); + if (IS_ERR(hws[ST_CLK_MUX])) + return PTR_ERR(hws[ST_CLK_MUX]); clk_set_parent(hws[ST_CLK_MUX]->clk, hws[ST_CLK_48M]->clk); -- 2.25.1
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