From: Duoming Zhou <duoming@zju.edu.cn> To: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org, mturquette@baylibre.com, sboyd@kernel.org, michal.simek@amd.com, Duoming Zhou <duoming@zju.edu.cn> Subject: [PATCH v3] clk: zynq: Prevent null pointer dereference caused by kmalloc failure Date: Fri, 1 Mar 2024 15:03:36 +0800 [thread overview] Message-ID: <20240301070336.13700-1-duoming@zju.edu.cn> (raw) The kmalloc() in zynq_clk_setup() will return null if the physical memory has run out. As a result, if we use snprintf() to write data to the null address, the null pointer dereference bug will happen. This patch uses a stack variable to replace the kmalloc(). Fixes: 0ee52b157b8e ("clk: zynq: Add clock controller driver") Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> --- Changes in v3: - Put stack variable in the head of the function and remove variable tmp. drivers/clk/zynq/clkc.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/drivers/clk/zynq/clkc.c b/drivers/clk/zynq/clkc.c index 7bdeaff2bfd..45479653c3b 100644 --- a/drivers/clk/zynq/clkc.c +++ b/drivers/clk/zynq/clkc.c @@ -215,7 +215,7 @@ static void __init zynq_clk_setup(struct device_node *np) int i; u32 tmp; int ret; - char *clk_name; + char clk_name[16]; unsigned int fclk_enable = 0; const char *clk_output_name[clk_max]; const char *cpu_parents[4]; @@ -426,12 +426,10 @@ static void __init zynq_clk_setup(struct device_node *np) "gem1_emio_mux", CLK_SET_RATE_PARENT, SLCR_GEM1_CLK_CTRL, 0, 0, &gem1clk_lock); - tmp = strlen("mio_clk_00x"); - clk_name = kmalloc(tmp, GFP_KERNEL); for (i = 0; i < NUM_MIO_PINS; i++) { int idx; - snprintf(clk_name, tmp, "mio_clk_%2.2d", i); + snprintf(clk_name, 16, "mio_clk_%2.2d", i); idx = of_property_match_string(np, "clock-names", clk_name); if (idx >= 0) can_mio_mux_parents[i] = of_clk_get_parent_name(np, @@ -439,7 +437,6 @@ static void __init zynq_clk_setup(struct device_node *np) else can_mio_mux_parents[i] = dummy_nm; } - kfree(clk_name); clk_register_mux(NULL, "can_mux", periph_parents, 4, CLK_SET_RATE_NO_REPARENT, SLCR_CAN_CLK_CTRL, 4, 2, 0, &canclk_lock); -- 2.17.1
WARNING: multiple messages have this Message-ID (diff)
From: Duoming Zhou <duoming@zju.edu.cn> To: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org, mturquette@baylibre.com, sboyd@kernel.org, michal.simek@amd.com, Duoming Zhou <duoming@zju.edu.cn> Subject: [PATCH v3] clk: zynq: Prevent null pointer dereference caused by kmalloc failure Date: Fri, 1 Mar 2024 15:03:36 +0800 [thread overview] Message-ID: <20240301070336.13700-1-duoming@zju.edu.cn> (raw) The kmalloc() in zynq_clk_setup() will return null if the physical memory has run out. As a result, if we use snprintf() to write data to the null address, the null pointer dereference bug will happen. This patch uses a stack variable to replace the kmalloc(). Fixes: 0ee52b157b8e ("clk: zynq: Add clock controller driver") Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> --- Changes in v3: - Put stack variable in the head of the function and remove variable tmp. drivers/clk/zynq/clkc.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/drivers/clk/zynq/clkc.c b/drivers/clk/zynq/clkc.c index 7bdeaff2bfd..45479653c3b 100644 --- a/drivers/clk/zynq/clkc.c +++ b/drivers/clk/zynq/clkc.c @@ -215,7 +215,7 @@ static void __init zynq_clk_setup(struct device_node *np) int i; u32 tmp; int ret; - char *clk_name; + char clk_name[16]; unsigned int fclk_enable = 0; const char *clk_output_name[clk_max]; const char *cpu_parents[4]; @@ -426,12 +426,10 @@ static void __init zynq_clk_setup(struct device_node *np) "gem1_emio_mux", CLK_SET_RATE_PARENT, SLCR_GEM1_CLK_CTRL, 0, 0, &gem1clk_lock); - tmp = strlen("mio_clk_00x"); - clk_name = kmalloc(tmp, GFP_KERNEL); for (i = 0; i < NUM_MIO_PINS; i++) { int idx; - snprintf(clk_name, tmp, "mio_clk_%2.2d", i); + snprintf(clk_name, 16, "mio_clk_%2.2d", i); idx = of_property_match_string(np, "clock-names", clk_name); if (idx >= 0) can_mio_mux_parents[i] = of_clk_get_parent_name(np, @@ -439,7 +437,6 @@ static void __init zynq_clk_setup(struct device_node *np) else can_mio_mux_parents[i] = dummy_nm; } - kfree(clk_name); clk_register_mux(NULL, "can_mux", periph_parents, 4, CLK_SET_RATE_NO_REPARENT, SLCR_CAN_CLK_CTRL, 4, 2, 0, &canclk_lock); -- 2.17.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2024-03-01 7:03 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-03-01 7:03 Duoming Zhou [this message] 2024-03-01 7:03 ` [PATCH v3] clk: zynq: Prevent null pointer dereference caused by kmalloc failure Duoming Zhou 2024-03-01 7:05 ` Michal Simek 2024-03-01 7:05 ` Michal Simek 2024-03-01 7:24 ` duoming 2024-03-01 7:24 ` duoming 2024-03-01 7:30 ` Michal Simek 2024-03-01 7:30 ` Michal Simek 2024-03-01 7:54 ` duoming 2024-03-01 7:54 ` duoming
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