Ensure that zfs diff prints unicode safely.

In the stream_bytes() library function used by `zfs diff`, explicitly
cast each byte in the input string to an unsigned character so that the
Linux fprintf() correctly escapes to octal and does not mangle the output.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1172

diff --git a/lib/libzfs/libzfs_diff.c b/lib/libzfs/libzfs_diff.c
index 8140a70..eb05f4d 100644 (file)
--- a/lib/libzfs/libzfs_diff.c
+++ b/lib/libzfs/libzfs_diff.c
@@ -141,7 +141,7 @@ stream_bytes(FILE *fp, const char *string)
                if (*string > ' ' && *string != '\\' && *string < '\177')
                        (void) fprintf(fp, "%c", *string++);
                else
-                       (void) fprintf(fp, "\\%03o", *string++);
+                       (void) fprintf(fp, "\\%03o", (unsigned char)*string++);
        }
 }