[PATCH] clk: stm32: Fix out-by-one error path in the index lookup

[PATCH] clk: stm32: Fix out-by-one error path in the index lookup

[Daniel Thompson]

If stm32f4_rcc_lookup() is called with primary == 0 and secondary == 192
then it will read beyond the end of the table array due to an out-by-one
error in the range check.

In addition to the fixing the inequality we also modify the r.h.s. to
make it even more explicit that we are comparing against the size of
table in bits.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
---
 drivers/clk/clk-stm32f4.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/clk-stm32f4.c b/drivers/clk/clk-stm32f4.c
index c825bbd..148c151 100644
--- a/drivers/clk/clk-stm32f4.c
+++ b/drivers/clk/clk-stm32f4.c
@@ -268,7 +268,7 @@ static int stm32f4_rcc_lookup_clk_idx(u8 primary, u8 secondary)
 	memcpy(table, stm32f42xx_gate_map, sizeof(table));

 	/* only bits set in table can be used as indices */
-	if (WARN_ON(secondary > 8 * sizeof(table) ||
+	if (WARN_ON(secondary >= BITS_PER_BYTE * sizeof(table) ||
 		    0 == (table[BIT_ULL_WORD(secondary)] &
 			  BIT_ULL_MASK(secondary))))
 		return -EINVAL;
--
2.4.3

Re: [PATCH] clk: stm32: Fix out-by-one error path in the index lookup

[Maxime Coquelin]

Hi Daniel,

2015-06-28 11:55 GMT+02:00 Daniel Thompson <daniel.thompson@linaro.org>:
> If stm32f4_rcc_lookup() is called with primary == 0 and secondary == 192
> then it will read beyond the end of the table array due to an out-by-one
> error in the range check.
>
> In addition to the fixing the inequality we also modify the r.h.s. to
> make it even more explicit that we are comparing against the size of
> table in bits.
>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
> ---
>  drivers/clk/clk-stm32f4.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>

Thanks for the patch.

Acked-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>

Regards,
Maxime

Re: [PATCH] clk: stm32: Fix out-by-one error path in the index lookup

[Stephen Boyd]

On 06/28, Daniel Thompson wrote:
> If stm32f4_rcc_lookup() is called with primary == 0 and secondary == 192
> then it will read beyond the end of the table array due to an out-by-one
> error in the range check.
> 
> In addition to the fixing the inequality we also modify the r.h.s. to
> make it even more explicit that we are comparing against the size of
> table in bits.
> 
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
> ---

Applied to clk-fixes

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