[PATCH v2 06/13] telemetry: limit characters allowed in dictionary names

[Bruce Richardson <bruce.richardson@intel.com>]

To save issues with encoding the names of values in dicts, we limit the
allowed names to a subset of character values. This list of allowed
characters can be expanded as necessary in future.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
---
 lib/telemetry/rte_telemetry.h  |  8 ++++++++
 lib/telemetry/telemetry_data.c | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/lib/telemetry/rte_telemetry.h b/lib/telemetry/rte_telemetry.h
index d586dd0fc1..a0d21d6b7f 100644
--- a/lib/telemetry/rte_telemetry.h
+++ b/lib/telemetry/rte_telemetry.h
@@ -64,6 +64,10 @@ rte_tel_data_start_array(struct rte_tel_data *d, enum rte_tel_value_type type);
 /**
  * Start a dictionary of values for returning from a callback
  *
+ * Dictionaries consist of key-values pairs to be returned, where the keys,
+ * or names, are strings and the values can be any of the types supported by telemetry.
+ * Name strings may only contain alphanumeric characters as well as '_' or '/'
+ *
  * @param d
  *   The data structure passed to the callback
  * @return
@@ -159,6 +163,7 @@ rte_tel_data_add_array_container(struct rte_tel_data *d,
  *   The data structure passed to the callback
  * @param name
  *   The name the value is to be stored under in the dict
+ *   Must contain only alphanumeric characters or the symbols: '_' or '/'
  * @param val
  *   The string to be stored in the dict
  * @return
@@ -177,6 +182,7 @@ rte_tel_data_add_dict_string(struct rte_tel_data *d, const char *name,
  *   The data structure passed to the callback
  * @param name
  *   The name the value is to be stored under in the dict
+ *   Must contain only alphanumeric characters or the symbols: '_' or '/'
  * @param val
  *   The number to be stored in the dict
  * @return
@@ -193,6 +199,7 @@ rte_tel_data_add_dict_int(struct rte_tel_data *d, const char *name, int val);
  *   The data structure passed to the callback
  * @param name
  *   The name the value is to be stored under in the dict
+ *   Must contain only alphanumeric characters or the symbols: '_' or '/'
  * @param val
  *   The number to be stored in the dict
  * @return
@@ -212,6 +219,7 @@ rte_tel_data_add_dict_u64(struct rte_tel_data *d,
  *   The data structure passed to the callback
  * @param name
  *   The name the value is to be stored under in the dict.
+ *   Must contain only alphanumeric characters or the symbols: '_' or '/'
  * @param val
  *   The pointer to the container to be stored in the dict.
  * @param keep
diff --git a/lib/telemetry/telemetry_data.c b/lib/telemetry/telemetry_data.c
index e14ae3c4d4..b5cd74b25b 100644
--- a/lib/telemetry/telemetry_data.c
+++ b/lib/telemetry/telemetry_data.c
@@ -3,6 +3,8 @@
  */
 
 #undef RTE_USE_LIBBSD
+#include <stdbool.h>
+
 #include <rte_string_fns.h>
 
 #include "telemetry_data.h"
@@ -92,6 +94,24 @@ rte_tel_data_add_array_container(struct rte_tel_data *d,
 	return 0;
 }
 
+static bool
+valid_name(const char *name)
+{
+	char allowed[128] = {
+			['0' ... '9'] = 1,
+			['A' ... 'Z'] = 1,
+			['a' ... 'z'] = 1,
+			['_'] = 1,
+			['/'] = 1,
+	};
+	while (*name != '\0') {
+		if ((size_t)*name >= RTE_DIM(allowed) || allowed[(int)*name] == 0)
+			return false;
+		name++;
+	}
+	return true;
+}
+
 int
 rte_tel_data_add_dict_string(struct rte_tel_data *d, const char *name,
 		const char *val)
@@ -104,6 +124,9 @@ rte_tel_data_add_dict_string(struct rte_tel_data *d, const char *name,
 	if (d->data_len >= RTE_TEL_MAX_DICT_ENTRIES)
 		return -ENOSPC;
 
+	if (!valid_name(name))
+		return -EINVAL;
+
 	d->data_len++;
 	e->type = RTE_TEL_STRING_VAL;
 	vbytes = strlcpy(e->value.sval, val, RTE_TEL_MAX_STRING_LEN);
@@ -123,6 +146,9 @@ rte_tel_data_add_dict_int(struct rte_tel_data *d, const char *name, int val)
 	if (d->data_len >= RTE_TEL_MAX_DICT_ENTRIES)
 		return -ENOSPC;
 
+	if (!valid_name(name))
+		return -EINVAL;
+
 	d->data_len++;
 	e->type = RTE_TEL_INT_VAL;
 	e->value.ival = val;
@@ -140,6 +166,9 @@ rte_tel_data_add_dict_u64(struct rte_tel_data *d,
 	if (d->data_len >= RTE_TEL_MAX_DICT_ENTRIES)
 		return -ENOSPC;
 
+	if (!valid_name(name))
+		return -EINVAL;
+
 	d->data_len++;
 	e->type = RTE_TEL_U64_VAL;
 	e->value.u64val = val;
@@ -161,6 +190,9 @@ rte_tel_data_add_dict_container(struct rte_tel_data *d, const char *name,
 	if (d->data_len >= RTE_TEL_MAX_DICT_ENTRIES)
 		return -ENOSPC;
 
+	if (!valid_name(name))
+		return -EINVAL;
+
 	d->data_len++;
 	e->type = RTE_TEL_CONTAINER;
 	e->value.container.data = val;
-- 
2.34.1