From: Dan Carpenter <dan.carpenter@oracle.com> To: Sudeep Holla <sudeep.holla@arm.com> Cc: Cristian Marussi <cristian.marussi@arm.com>, "Jon Medhurst (Tixy)" <tixy@linaro.org>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH] firmware: arm_scpi: prevent ternary sign expansion bug Date: Thu, 22 Apr 2021 12:02:29 +0300 [thread overview] Message-ID: <YIE7pdqV/h10tEAK@mwanda> (raw) How type promotion works in ternary expressions is a bit tricky. The problem is that scpi_clk_get_val() returns longs, "ret" is a int which holds a negative error code, and le32_to_cpu() is an unsigned int. We want the negative error code to be cast to a negative long. But because le32_to_cpu() is an u32 then "ret" is type promoted to u32 and becomes a high positive and then it is promoted to long and it is still a high positive value. Fix this by getting rid of the ternary. Fixes: 8cb7cf56c9fe ("firmware: add support for ARM System Control and Power Interface(SCPI) protocol") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- drivers/firmware/arm_scpi.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/arm_scpi.c b/drivers/firmware/arm_scpi.c index d0dee37ad522..3bf61854121d 100644 --- a/drivers/firmware/arm_scpi.c +++ b/drivers/firmware/arm_scpi.c @@ -552,8 +552,10 @@ static unsigned long scpi_clk_get_val(u16 clk_id) ret = scpi_send_message(CMD_GET_CLOCK_VALUE, &le_clk_id, sizeof(le_clk_id), &rate, sizeof(rate)); + if (ret) + return ret; - return ret ? ret : le32_to_cpu(rate); + return le32_to_cpu(rate); } static int scpi_clk_set_val(u16 clk_id, unsigned long rate) -- 2.30.2
WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com> To: Sudeep Holla <sudeep.holla@arm.com> Cc: Cristian Marussi <cristian.marussi@arm.com>, "Jon Medhurst (Tixy)" <tixy@linaro.org>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH] firmware: arm_scpi: prevent ternary sign expansion bug Date: Thu, 22 Apr 2021 12:02:29 +0300 [thread overview] Message-ID: <YIE7pdqV/h10tEAK@mwanda> (raw) How type promotion works in ternary expressions is a bit tricky. The problem is that scpi_clk_get_val() returns longs, "ret" is a int which holds a negative error code, and le32_to_cpu() is an unsigned int. We want the negative error code to be cast to a negative long. But because le32_to_cpu() is an u32 then "ret" is type promoted to u32 and becomes a high positive and then it is promoted to long and it is still a high positive value. Fix this by getting rid of the ternary. Fixes: 8cb7cf56c9fe ("firmware: add support for ARM System Control and Power Interface(SCPI) protocol") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- drivers/firmware/arm_scpi.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/arm_scpi.c b/drivers/firmware/arm_scpi.c index d0dee37ad522..3bf61854121d 100644 --- a/drivers/firmware/arm_scpi.c +++ b/drivers/firmware/arm_scpi.c @@ -552,8 +552,10 @@ static unsigned long scpi_clk_get_val(u16 clk_id) ret = scpi_send_message(CMD_GET_CLOCK_VALUE, &le_clk_id, sizeof(le_clk_id), &rate, sizeof(rate)); + if (ret) + return ret; - return ret ? ret : le32_to_cpu(rate); + return le32_to_cpu(rate); } static int scpi_clk_set_val(u16 clk_id, unsigned long rate) -- 2.30.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2021-04-22 9:03 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-22 9:02 Dan Carpenter [this message] 2021-04-22 9:02 ` [PATCH] firmware: arm_scpi: prevent ternary sign expansion bug Dan Carpenter 2021-04-22 10:17 ` Cristian Marussi 2021-04-22 10:17 ` Cristian Marussi 2021-04-22 11:34 ` Cristian Marussi 2021-04-22 11:34 ` Cristian Marussi 2021-04-22 17:46 ` Sudeep Holla 2021-04-22 17:46 ` Sudeep Holla 2021-04-24 6:43 ` Dan Carpenter 2021-04-24 6:43 ` Dan Carpenter 2021-04-28 10:03 ` Sudeep Holla 2021-04-28 10:03 ` Sudeep Holla
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