| Message ID | 20240301084437.16084-1-duoming@zju.edu.cn (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
| Series | [v4] clk: zynq: Prevent null pointer dereference caused by kmalloc failure | expand |
On 3/1/24 09:44, Duoming Zhou wrote: > 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") > Suggested-by: Michal Simek <michal.simek@amd.com> > Suggested-by: Stephen Boyd <sboyd@kernel.org> > Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> > --- > drivers/clk/zynq/clkc.c | 8 +++----- > 1 file changed, 3 insertions(+), 5 deletions(-) > > diff --git a/drivers/clk/zynq/clkc.c b/drivers/clk/zynq/clkc.c > index 7bdeaff2bfd..c28d3dacf0f 100644 > --- a/drivers/clk/zynq/clkc.c > +++ b/drivers/clk/zynq/clkc.c > @@ -42,6 +42,7 @@ static void __iomem *zynq_clkc_base; > #define SLCR_SWDT_CLK_SEL (zynq_clkc_base + 0x204) > > #define NUM_MIO_PINS 54 > +#define CLK_NAME_LEN 16 > > #define DBG_CLK_CTRL_CLKACT_TRC BIT(0) > #define DBG_CLK_CTRL_CPU_1XCLKACT BIT(1) > @@ -215,7 +216,7 @@ static void __init zynq_clk_setup(struct device_node *np) > int i; > u32 tmp; > int ret; > - char *clk_name; > + char clk_name[CLK_NAME_LEN]; > unsigned int fclk_enable = 0; > const char *clk_output_name[clk_max]; > const char *cpu_parents[4]; > @@ -426,12 +427,10 @@ 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, CLK_NAME_LEN, "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 +438,6 @@ 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); Acked-by: Michal Simek <michal.simek@amd.com> Thanks, Michal
Quoting Duoming Zhou (2024-03-01 00:44:37) > 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") > Suggested-by: Michal Simek <michal.simek@amd.com> > Suggested-by: Stephen Boyd <sboyd@kernel.org> > Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> > --- Applied to clk-next
diff --git a/drivers/clk/zynq/clkc.c b/drivers/clk/zynq/clkc.c index 7bdeaff2bfd..c28d3dacf0f 100644 --- a/drivers/clk/zynq/clkc.c +++ b/drivers/clk/zynq/clkc.c @@ -42,6 +42,7 @@ static void __iomem *zynq_clkc_base; #define SLCR_SWDT_CLK_SEL (zynq_clkc_base + 0x204) #define NUM_MIO_PINS 54 +#define CLK_NAME_LEN 16 #define DBG_CLK_CTRL_CLKACT_TRC BIT(0) #define DBG_CLK_CTRL_CPU_1XCLKACT BIT(1) @@ -215,7 +216,7 @@ static void __init zynq_clk_setup(struct device_node *np) int i; u32 tmp; int ret; - char *clk_name; + char clk_name[CLK_NAME_LEN]; unsigned int fclk_enable = 0; const char *clk_output_name[clk_max]; const char *cpu_parents[4]; @@ -426,12 +427,10 @@ 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, CLK_NAME_LEN, "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 +438,6 @@ 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);
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") Suggested-by: Michal Simek <michal.simek@amd.com> Suggested-by: Stephen Boyd <sboyd@kernel.org> Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> --- drivers/clk/zynq/clkc.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)