diff: fix SEGV (NULL deref) in diff -N

diff --git a/coreutils/diff.c b/coreutils/diff.c
index fa6ef10..911bfcf 100644 (file)
--- a/coreutils/diff.c
+++ b/coreutils/diff.c
@@ -997,24 +997,30 @@ static void do_diff(char *dir1, char *path1, char *dir2, char *path2)
 {
        int flags = D_HEADER;
        int val;
+       char *fullpath1 = NULL; /* if -N */
+       char *fullpath2 = NULL;
 
-       char *fullpath1 = concat_path_file(dir1, path1);
-       char *fullpath2 = concat_path_file(dir2, path2);
+       if (path1)
+               fullpath1 = concat_path_file(dir1, path1);
+       if (path2)
+               fullpath2 = concat_path_file(dir2, path2);
 
-       if (stat(fullpath1, &stb1) != 0) {
+       if (!fullpath1 || stat(fullpath1, &stb1) != 0) {
                flags |= D_EMPTY1;
                memset(&stb1, 0, sizeof(stb1));
-               if (ENABLE_FEATURE_CLEAN_UP)
+               if (path2) {
                        free(fullpath1);
-               fullpath1 = concat_path_file(dir1, path2);
+                       fullpath1 = concat_path_file(dir1, path2);
+               }
        }
-       if (stat(fullpath2, &stb2) != 0) {
+       if (!fullpath2 || stat(fullpath2, &stb2) != 0) {
                flags |= D_EMPTY2;
                memset(&stb2, 0, sizeof(stb2));
                stb2.st_mode = stb1.st_mode;
-               if (ENABLE_FEATURE_CLEAN_UP)
+               if (path1) {
                        free(fullpath2);
-               fullpath2 = concat_path_file(dir2, path1);
+                       fullpath2 = concat_path_file(dir2, path1);
+               }
        }
 
        if (stb1.st_mode == 0)
@@ -1022,7 +1028,7 @@ static void do_diff(char *dir1, char *path1, char *dir2, char *path2)
 
        if (S_ISDIR(stb1.st_mode) && S_ISDIR(stb2.st_mode)) {
                printf("Common subdirectories: %s and %s\n", fullpath1, fullpath2);
-               return;
+               goto ret;
        }
 
        if (!S_ISREG(stb1.st_mode) && !S_ISDIR(stb1.st_mode))
@@ -1033,6 +1039,9 @@ static void do_diff(char *dir1, char *path1, char *dir2, char *path2)
                val = diffreg(fullpath1, fullpath2, flags);
 
        print_status(val, fullpath1, fullpath2, NULL);
+ ret:
+       free(fullpath1);
+       free(fullpath2);
 }
 #endif