libmultipath: check argument length in execute_program()

The 'path' argument of execute_program() is actually an
array with fixed length. So we should be using the same
length here to avoid overflows. And we should check the
number or arguments, too, as the list we're using is
static, too.

Signed-off-by: Hannes Reinecke <hare@suse.de>

diff --git a/libmultipath/callout.c b/libmultipath/callout.c
index 520343e..ae19051 100644 (file)
--- a/libmultipath/callout.c
+++ b/libmultipath/callout.c
@@ -17,17 +17,9 @@
 #include "checkers.h"
 #include "vector.h"
 #include "structs.h"
+#include "util.h"
 #include "debug.h"
 
-#define PROGRAM_SIZE   100
-#define FIELD_PROGRAM
-
-#define strfieldcpy(to, from) \
-do { \
-       to[sizeof(to)-1] = '\0'; \
-       strncpy(to, from, sizeof(to)-1); \
-} while (0)
-
 int execute_program(char *path, char *value, int len)
 {
        int retval;
@@ -36,16 +28,17 @@ int execute_program(char *path, char *value, int len)
        int fds[2], null_fd;
        pid_t pid;
        char *pos;
-       char arg[PROGRAM_SIZE];
-       char *argv[sizeof(arg) / 2];
+       char arg[CALLOUT_MAX_SIZE];
+       int argc = sizeof(arg) / 2;
+       char *argv[argc + 1];
        int i;
 
        i = 0;
 
        if (strchr(path, ' ')) {
-               strfieldcpy(arg, path);
+               strlcpy(arg, path, sizeof(arg));
                pos = arg;
-               while (pos != NULL) {
+               while (pos != NULL && i < argc) {
                        if (pos[0] == '\'') {
                                /* don't separate if in apostrophes */
                                pos++;

diff --git a/libmultipath/structs.h b/libmultipath/structs.h
index 78ba81e..e2d2e28 100644 (file)
--- a/libmultipath/structs.h
+++ b/libmultipath/structs.h
@@ -9,7 +9,7 @@
 #define PATH_STR_SIZE                  16
 #define PARAMS_SIZE            1024
 #define FILE_NAME_SIZE         256
-#define CALLOUT_MAX_SIZE       128
+#define CALLOUT_MAX_SIZE       256
 #define BLK_DEV_SIZE           33
 #define PATH_SIZE              512
 #define NAME_SIZE              512