file/config_file: reject non-numeric input in integer getters

config_get_int(), config_get_uint(), config_get_uint64() and
config_get_hex() all used this pattern:

    errno = 0;
    val = strtol(entry->value, NULL, 0);
    if (errno == 0) {
       *in = val;
       return true;
    }

strtol returns 0 (without setting errno) when handed a string that
has no leading digits at all -- so a config line like

    width = abc

silently produced width = 0 and the getter reported success.  The
user sees the setting "accepted" with a bogus value and no way to
tell anything went wrong.  config_get_size_t() in the same file
already used the correct pattern; this patch applies it to the
other four.

Each fixed getter now:

  - captures the end pointer from strtol/strtoul/strtoull
  - rejects if errno was set (overflow)
  - rejects if zero digits were consumed (end == entry->value)
  - rejects if trailing garbage remains (*end != '\0')
  - for config_get_int / config_get_uint / config_get_hex, also
    rejects values outside the destination type's range (strtol
    on 64-bit systems returns a 64-bit long that must fit in int)

Behavioural change: values that previously silently became zero
now return false and leave *in untouched.  This matches the
documented "@return true if found, otherwise false" contract in
config_file.h -- the prior behaviour violated it by returning true
for not-a-number strings.  Callers that relied on the bogus zero
were already silently broken; they now get explicit failure and
can fall back to a default.

Author: LibretroAdmin

libretro-common/file/config_file.c

@@ -25,6 +25,7 @@
 #include <stdio.h>
 #include <ctype.h>
 #include <errno.h>
+#include <limits.h>
 
 #include <retro_miscellaneous.h>
 #include <compat/strl.h>
@@ -963,17 +964,22 @@ bool config_get_float(config_file_t *conf, const char *key, float *in)
 bool config_get_int(config_file_t *conf, const char *key, int *in)
 {
    const struct config_entry_list *entry = config_get_entry(conf, key);
-   errno = 0;
 
    if (entry)
    {
-      int val = (int)strtol(entry->value, NULL, 0);
+      long  val;
+      char *end = NULL;
+      errno = 0;
+      val   = strtol(entry->value, &end, 0);
 
-      if (errno == 0)
-      {
-         *in = val;
-         return true;
-      }
+      if (errno != 0 || end == entry->value || *end != '\0')
+         return false;
+
+      if (val < INT_MIN || val > INT_MAX)
+         return false;
+
+      *in = (int)val;
+      return true;
    }
 
    return false;
@@ -1009,17 +1015,19 @@ bool config_get_size_t(config_file_t *conf, const char *key, size_t *in)
 bool config_get_uint64(config_file_t *conf, const char *key, uint64_t *in)
 {
    const struct config_entry_list *entry = config_get_entry(conf, key);
-   errno = 0;
 
    if (entry)
    {
-      uint64_t val = (uint64_t)strtoull(entry->value, NULL, 0);
+      uint64_t val;
+      char    *end = NULL;
+      errno = 0;
+      val   = (uint64_t)strtoull(entry->value, &end, 0);
 
-      if (errno == 0)
-      {
-         *in = val;
-         return true;
-      }
+      if (errno != 0 || end == entry->value || *end != '\0')
+         return false;
+
+      *in = val;
+      return true;
    }
    return false;
 }
@@ -1028,17 +1036,22 @@ bool config_get_uint64(config_file_t *conf, const char *key, uint64_t *in)
 bool config_get_uint(config_file_t *conf, const char *key, unsigned *in)
 {
    const struct config_entry_list *entry = config_get_entry(conf, key);
-   errno = 0;
 
    if (entry)
    {
-      unsigned val = (unsigned)strtoul(entry->value, NULL, 0);
+      unsigned long  val;
+      char          *end = NULL;
+      errno = 0;
+      val   = strtoul(entry->value, &end, 0);
 
-      if (errno == 0)
-      {
-         *in = val;
-         return true;
-      }
+      if (errno != 0 || end == entry->value || *end != '\0')
+         return false;
+
+      if (val > UINT_MAX)
+         return false;
+
+      *in = (unsigned)val;
+      return true;
    }
 
    return false;
@@ -1047,17 +1060,22 @@ bool config_get_uint(config_file_t *conf, const char *key, unsigned *in)
 bool config_get_hex(config_file_t *conf, const char *key, unsigned *in)
 {
    const struct config_entry_list *entry = config_get_entry(conf, key);
-   errno = 0;
 
    if (entry)
    {
-      unsigned val = (unsigned)strtoul(entry->value, NULL, 16);
+      unsigned long  val;
+      char          *end = NULL;
+      errno = 0;
+      val   = strtoul(entry->value, &end, 16);
 
-      if (errno == 0)
-      {
-         *in = val;
-         return true;
-      }
+      if (errno != 0 || end == entry->value || *end != '\0')
+         return false;
+
+      if (val > UINT_MAX)
+         return false;
+
+      *in = (unsigned)val;
+      return true;
    }
 
    return false;

libretro-common/samples/file/archive_file/Makefile

@@ -0,0 +1,41 @@
+TARGET := archive_zip_test
+
+LIBRETRO_COMM_DIR := ../../..
+
+SOURCES := \
+	archive_zip_test.c \
+	$(LIBRETRO_COMM_DIR)/compat/fopen_utf8.c \
+	$(LIBRETRO_COMM_DIR)/compat/compat_strl.c \
+	$(LIBRETRO_COMM_DIR)/compat/compat_strcasestr.c \
+	$(LIBRETRO_COMM_DIR)/compat/compat_posix_string.c \
+	$(LIBRETRO_COMM_DIR)/encodings/encoding_crc32.c \
+	$(LIBRETRO_COMM_DIR)/encodings/encoding_utf.c \
+	$(LIBRETRO_COMM_DIR)/file/archive_file.c \
+	$(LIBRETRO_COMM_DIR)/file/archive_file_zlib.c \
+	$(LIBRETRO_COMM_DIR)/file/file_path.c \
+	$(LIBRETRO_COMM_DIR)/file/file_path_io.c \
+	$(LIBRETRO_COMM_DIR)/lists/string_list.c \
+	$(LIBRETRO_COMM_DIR)/streams/file_stream.c \
+	$(LIBRETRO_COMM_DIR)/streams/trans_stream.c \
+	$(LIBRETRO_COMM_DIR)/streams/trans_stream_pipe.c \
+	$(LIBRETRO_COMM_DIR)/streams/trans_stream_zlib.c \
+	$(LIBRETRO_COMM_DIR)/vfs/vfs_implementation.c \
+	$(LIBRETRO_COMM_DIR)/time/rtime.c
+
+OBJS := $(SOURCES:.c=.o)
+
+CFLAGS += -Wall -pedantic -std=gnu99 -g -DHAVE_ZLIB -I$(LIBRETRO_COMM_DIR)/include
+LDFLAGS += -lz
+
+all: $(TARGET)
+
+%.o: %.c
+	$(CC) -c -o $@ $< $(CFLAGS)
+
+$(TARGET): $(OBJS)
+	$(CC) -o $@ $^ $(LDFLAGS)
+
+clean:
+	rm -f $(TARGET) $(OBJS)
+
+.PHONY: clean