[PATCH v2 02/11] coresight: etm4x: Fix input validation for sysfs.

Mike Leach
2019-08-29T21:34:09Z

A number of issues are fixed relating to sysfs input validation:-

1) bb_ctrl_store() - incorrect compare of bit select field to absolute
value. Reworked per ETMv4 specification.
2) seq_event_store() - incorrect mask value - register has two
event values.
3) cyc_threshold_store() - must mask with max before checking min
otherwise wrapped values can set illegal value below min.
4) res_ctrl_store() - update to mask off all res0 bits.

Reviewed-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Mike Leach <mike.leach@linaro.org>
---
.../coresight/coresight-etm4x-sysfs.c | 21 ++++++++++++-------
1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index b6984be0c515..cc8156318018 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -652,10 +652,13 @@ static ssize_t cyc_threshold_store(struct device *dev,

if (kstrtoul(buf, 16, &val))
return -EINVAL;
+
+ /* mask off max threshold before checking min value */
+ val &= ETM_CYC_THRESHOLD_MASK;
if (val < drvdata->ccitmin)
return -EINVAL;

- config->ccctlr = val & ETM_CYC_THRESHOLD_MASK;
+ config->ccctlr = val;
return size;
}
static DEVICE_ATTR_RW(cyc_threshold);
@@ -686,14 +689,16 @@ static ssize_t bb_ctrl_store(struct device *dev,
return -EINVAL;
if (!drvdata->nr_addr_cmp)
return -EINVAL;
+
/*
- * Bit[7:0] selects which address range comparator is used for
- * branch broadcast control.
+ * Bit[8] controls include(1) / exclude(0), bits[0-7] select
+ * individual range comparators. If include then at least 1
+ * range must be selected.
*/
- if (BMVAL(val, 0, 7) > drvdata->nr_addr_cmp)
+ if ((val & BIT(8)) && (BMVAL(val, 0, 7) == 0))
return -EINVAL;

- config->bb_ctrl = val;
+ config->bb_ctrl = val & GENMASK(8, 0);
return size;
}
static DEVICE_ATTR_RW(bb_ctrl);
@@ -1324,8 +1329,8 @@ static ssize_t seq_event_store(struct device *dev,

spin_lock(&drvdata->spinlock);
idx = config->seq_idx;
- /* RST, bits[7:0] */
- config->seq_ctrl[idx] = val & 0xFF;
+ /* Seq control has two masks B[15:8] F[7:0] */
+ config->seq_ctrl[idx] = val & 0xFFFF;
spin_unlock(&drvdata->spinlock);
return size;
}
@@ -1580,7 +1585,7 @@ static ssize_t res_ctrl_store(struct device *dev,
if (idx % 2 != 0)
/* PAIRINV, bit[21] */
val &= ~BIT(21);
- config->res_ctrl[idx] = val;
+ config->res_ctrl[idx] = val & GENMASK(21, 0);
spin_unlock(&drvdata->spinlock);
return size;
}
--
2.17.1