[PATCH v13 16/17] cfgfile: add length checks and increase line buffer

Stephen Hemminger
2026-01-27T16:34:55Z

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@networkplumber.org>
---
doc/guides/rel_notes/release_26_03.rst | 2 ++
lib/cfgfile/rte_cfgfile.c | 42 ++++++++++++++++++++------
lib/cfgfile/rte_cfgfile.h | 6 +++-
3 files changed, 40 insertions(+), 10 deletions(-)

diff --git a/doc/guides/rel_notes/release_26_03.rst b/doc/guides/rel_notes/release_26_03.rst
index d643206167..d0c504ba7b 100644
--- a/doc/guides/rel_notes/release_26_03.rst
+++ b/doc/guides/rel_notes/release_26_03.rst
@@ -94,6 +94,8 @@ API Changes
* hash: name parameter must be less than RTE_HASH_NAMESIZE.
* efd: name must be less than RTE_EFD_NAMESIZE.
* tailq: name must be less than RTE_TAILQ_NAMESIZE.
+ * cfgfile: name must be less than CFG_NAME_LEN
+ and value must be less than CFG_VALUE_LEN.

ABI Changes
diff --git a/lib/cfgfile/rte_cfgfile.c b/lib/cfgfile/rte_cfgfile.c
index 9723ec756f..95151b231c 100644
--- a/lib/cfgfile/rte_cfgfile.c
+++ b/lib/cfgfile/rte_cfgfile.c
@@ -2,11 +2,18 @@
* Copyright(c) 2010-2014 Intel Corporation
*/

+#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
+#include <limits.h>
+
+#ifndef LINE_MAX
+#define LINE_MAX 2048
+#endif
+
#include <eal_export.h>
#include <rte_string_fns.h>
#include <rte_common.h>
@@ -106,6 +113,9 @@ 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 +177,16 @@ 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 +233,13 @@ 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 +280,13 @@ 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 +366,9 @@ 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 +404,6 @@ 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 +417,7 @@ 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)
diff --git a/lib/cfgfile/rte_cfgfile.h b/lib/cfgfile/rte_cfgfile.h
index 232c65c77b..761420facd 100644
--- a/lib/cfgfile/rte_cfgfile.h
+++ b/lib/cfgfile/rte_cfgfile.h
@@ -131,7 +131,11 @@ rte_cfgfile_add_section(struct rte_cfgfile *cfg, const char *sectionname);
* @param entryvalue
* Entry value to add.
* @return
- * 0 on success, -EEXIST if entry already exist, -EINVAL if bad argument
+ * 0 on success
+ * -EEXIST if entry already exist
+ * -EINVAL if bad argument
+ * -ENAMETOOLONG - entry exceeds CFG_NAME_LEN
+ * or value exceeds CFG_VALUE_LEN
*/
int rte_cfgfile_add_entry(struct rte_cfgfile *cfg,
const char *sectionname, const char *entryname,
--
2.51.0