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

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>
Acked-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Fixes: 358bdf892f6b ("clk: stm32: Add clock driver for STM32F4[23]xxx devices")
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

diff --git a/drivers/clk/clk-stm32f4.c b/drivers/clk/clk-stm32f4.c
index b9b12a7..3f6f7ad 100644 (file)
--- 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;