[Xen-devel] [PATCH] xc_linux_build - proactively check for NULL string arguments

[B Thomas <bjthomas3@xxxxxxxxx>]

[Forgot to say "please", errr, tag this as [PATCH]...oops]

Proactively check for NULL strings passed into xc_linx_build.  Either DTRT or return error if detected.  A NULL cmdline, for example, would currently generate a segfault.

Signed-off-by:  Ben Thomas   
bjthomas3@xxxxxxxxx



diff -r 5b30599761b3 tools/libxc/xc_linux_build.c
--- a/tools/libxc/xc_linux_build.c      Mon Jan  2 10:35:29 2006
+++ b/tools/libxc/xc_linux_build.c      Wed Jan  4 19:31:22 2006
@@ -689,8 +689,11 @@
         start_info->mod_start    = vinitrd_start;
         start_info->mod_len      = initrd_len;
     }
-    strncpy((char *)start_info->cmd_line, cmdline, MAX_GUEST_CMDLINE);
-    start_info->cmd_line[MAX_GUEST_CMDLINE-1] = '\0';
+    if (cmdline != NULL) {
+        strncpy((char *)start_info->cmd_line, cmdline, MAX_GUEST_CMDLINE);
+        start_info->cmd_line[MAX_GUEST_CMDLINE-1] = '\0';
+    } else
+        start_info->cmd_line[0] = '\0';
     munmap(start_info, PAGE_SIZE);

     /* shared_info page starts its life empty. */
@@ -751,7 +754,8 @@
         goto error_out;
     }

-    if ( (image = xc_read_kernel_image(image_name, &image_size)) == NULL )
+    if ( (image_name == NULL) ||
+         ((image = xc_read_kernel_image(image_name, &image_size)) == NULL ) )
         goto error_out;

     if ( (ramdisk_name != NULL) && (strlen(ramdisk_name) != 0) )


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