diff options
Diffstat (limited to 'drivers/hwtracing/coresight/coresight-etm3x-sysfs.c')
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-etm3x-sysfs.c | 43 |
1 files changed, 37 insertions, 6 deletions
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c index 9435c1481f61..75487b3fad86 100644 --- a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c +++ b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c @@ -4,6 +4,7 @@ * Author: Mathieu Poirier <mathieu.poirier@linaro.org> */ +#include <linux/pid_namespace.h> #include <linux/pm_runtime.h> #include <linux/sysfs.h> #include "coresight-etm.h" @@ -1025,8 +1026,15 @@ static ssize_t ctxid_pid_show(struct device *dev, struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent); struct etm_config *config = &drvdata->config; + /* + * Don't use contextID tracing if coming from a PID namespace. See + * comment in ctxid_pid_store(). + */ + if (task_active_pid_ns(current) != &init_pid_ns) + return -EINVAL; + spin_lock(&drvdata->spinlock); - val = config->ctxid_vpid[config->ctxid_idx]; + val = config->ctxid_pid[config->ctxid_idx]; spin_unlock(&drvdata->spinlock); return sprintf(buf, "%#lx\n", val); @@ -1037,19 +1045,28 @@ static ssize_t ctxid_pid_store(struct device *dev, const char *buf, size_t size) { int ret; - unsigned long vpid, pid; + unsigned long pid; struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent); struct etm_config *config = &drvdata->config; - ret = kstrtoul(buf, 16, &vpid); + /* + * When contextID tracing is enabled the tracers will insert the + * value found in the contextID register in the trace stream. But if + * a process is in a namespace the PID of that process as seen from the + * namespace won't be what the kernel sees, something that makes the + * feature confusing and can potentially leak kernel only information. + * As such refuse to use the feature if @current is not in the initial + * PID namespace. + */ + if (task_active_pid_ns(current) != &init_pid_ns) + return -EINVAL; + + ret = kstrtoul(buf, 16, &pid); if (ret) return ret; - pid = coresight_vpid_to_pid(vpid); - spin_lock(&drvdata->spinlock); config->ctxid_pid[config->ctxid_idx] = pid; - config->ctxid_vpid[config->ctxid_idx] = vpid; spin_unlock(&drvdata->spinlock); return size; @@ -1063,6 +1080,13 @@ static ssize_t ctxid_mask_show(struct device *dev, struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent); struct etm_config *config = &drvdata->config; + /* + * Don't use contextID tracing if coming from a PID namespace. See + * comment in ctxid_pid_store(). + */ + if (task_active_pid_ns(current) != &init_pid_ns) + return -EINVAL; + val = config->ctxid_mask; return sprintf(buf, "%#lx\n", val); } @@ -1076,6 +1100,13 @@ static ssize_t ctxid_mask_store(struct device *dev, struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent); struct etm_config *config = &drvdata->config; + /* + * Don't use contextID tracing if coming from a PID namespace. See + * comment in ctxid_pid_store(). + */ + if (task_active_pid_ns(current) != &init_pid_ns) + return -EINVAL; + ret = kstrtoul(buf, 16, &val); if (ret) return ret; |