[PATCH v6 17/18] cfgfile: add length checks and increase line buffer

[Stephen Hemminger]

When adding values to config info, add string length checks instead
of silently truncating. Increase the size of the buffer used to read
from a config file so that there will be enough space for longest
entries.

Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
 lib/cfgfile/rte_cfgfile.c | 36 +++++++++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 9 deletions(-)

diff --git a/lib/cfgfile/rte_cfgfile.c b/lib/cfgfile/rte_cfgfile.c
index 9723ec756f..74a8bf7aae 100644
--- a/lib/cfgfile/rte_cfgfile.c
+++ b/lib/cfgfile/rte_cfgfile.c
@@ -2,6 +2,7 @@
  * Copyright(c) 2010-2014 Intel Corporation
  */
 
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -106,6 +107,9 @@ static int
 _add_entry(struct rte_cfgfile_section *section, const char *entryname,
 		const char *entryvalue)
 {
+	if (strlen(entryname) >= CFG_NAME_LEN || strlen(entryvalue) >= CFG_VALUE_LEN)
+		return -ENAMETOOLONG;
+
 	/* resize entry structure if we don't have room for more entries */
 	if (section->num_entries == section->allocated_entries) {
 		struct rte_cfgfile_entry *n_entries = realloc(
@@ -167,12 +171,16 @@ rte_cfgfile_load(const char *filename, int flags)
 					    &default_cfgfile_params);
 }
 
+/* Need enough space for largest name and value */
+static_assert(LINE_MAX > CFG_NAME_LEN + CFG_VALUE_LEN + 4,
+	      "not enough space for cfgfile name/value");
+
 RTE_EXPORT_SYMBOL(rte_cfgfile_load_with_params)
 struct rte_cfgfile *
 rte_cfgfile_load_with_params(const char *filename, int flags,
 			     const struct rte_cfgfile_parameters *params)
 {
-	char buffer[CFG_NAME_LEN + CFG_VALUE_LEN + 4];
+	char buffer[LINE_MAX];
 	int lineno = 0;
 	struct rte_cfgfile *cfg;
 
@@ -219,7 +227,13 @@ rte_cfgfile_load_with_params(const char *filename, int flags,
 			*end = '\0';
 			_strip(&buffer[1], end - &buffer[1]);
 
-			rte_cfgfile_add_section(cfg, &buffer[1]);
+			int ret = rte_cfgfile_add_section(cfg, &buffer[1]);
+			if (ret != 0) {
+				CFG_LOG(ERR,
+					"line %d - add section failed: %s",
+					lineno, strerror(-ret));
+				goto error1;
+			}
 		} else {
 			/* key and value line */
 			char *split[2] = {NULL};
@@ -260,8 +274,13 @@ rte_cfgfile_load_with_params(const char *filename, int flags,
 			if (cfg->num_sections == 0)
 				goto error1;
 
-			_add_entry(&cfg->sections[cfg->num_sections - 1],
-					split[0], split[1]);
+			int ret = _add_entry(&cfg->sections[cfg->num_sections - 1],
+					     split[0], split[1]);
+			if (ret != 0) {
+				CFG_LOG(ERR,
+					"line %d - add entry failed: %s", lineno, strerror(-ret));
+				goto error1;
+			}
 		}
 	}
 	fclose(f);
@@ -341,6 +360,9 @@ rte_cfgfile_add_section(struct rte_cfgfile *cfg, const char *sectionname)
 	if (sectionname == NULL)
 		return -EINVAL;
 
+	if (strlen(sectionname) >= CFG_NAME_LEN)
+		return -ENAMETOOLONG;
+
 	/* resize overall struct if we don't have room for more	sections */
 	if (cfg->num_sections == cfg->allocated_sections) {
 
@@ -376,8 +398,6 @@ int rte_cfgfile_add_entry(struct rte_cfgfile *cfg,
 		const char *sectionname, const char *entryname,
 		const char *entryvalue)
 {
-	int ret;
-
 	if ((cfg == NULL) || (sectionname == NULL) || (entryname == NULL)
 			|| (entryvalue == NULL))
 		return -EINVAL;
@@ -391,9 +411,7 @@ int rte_cfgfile_add_entry(struct rte_cfgfile *cfg,
 	if (curr_section == NULL)
 		return -EINVAL;
 
-	ret = _add_entry(curr_section, entryname, entryvalue);
-
-	return ret;
+	return _add_entry(curr_section, entryname, entryvalue);
 }
 
 RTE_EXPORT_SYMBOL(rte_cfgfile_set_entry)
-- 
2.51.0