From: Petteri Aimonen <jpa@git.mail.kapsi.fi>
Date: Sun, 14 Apr 2013 06:46:39 +0000 (+0300)
Subject: Handle unterminated strings when encoding.
X-Git-Tag: 3.99.1~14^2~378
X-Git-Url: https://gerrit.automotivelinux.org/gerrit/gitweb?a=commitdiff_plain;h=d2063ff0b63b3b4f2f2081e61874a3c2487c4994;p=apps%2Flow-level-can-service.git

Handle unterminated strings when encoding.

If the null terminator is not present, string will be limited to the
data size of the field.

If you are still using the pb_enc_string (deprecated since 0.1.3) from
callbacks, now would be an excellent time to stop. The pb_field_t for
the callback will not contain proper data_size. Use pb_encode_string()
instead.

Update issue 68
Status: FixedInGit
---

diff --git a/pb_encode.c b/pb_encode.c
index 48a3c95..0e048ac 100644
--- a/pb_encode.c
+++ b/pb_encode.c
@@ -461,8 +461,16 @@ bool checkreturn pb_enc_bytes(pb_ostream_t *stream, const pb_field_t *field, con
 
 bool checkreturn pb_enc_string(pb_ostream_t *stream, const pb_field_t *field, const void *src)
 {
-    UNUSED(field);
-    return pb_encode_string(stream, (const uint8_t*)src, strlen((const char*)src));
+    /* strnlen() is not always available, so just use a for-loop */
+    size_t size = 0;
+    const char *p = (const char*)src;
+    while (size < field->data_size && *p != '\0')
+    {
+        size++;
+        p++;
+    }
+
+    return pb_encode_string(stream, (const uint8_t*)src, size);
 }
 
 bool checkreturn pb_enc_submessage(pb_ostream_t *stream, const pb_field_t *field, const void *src)
diff --git a/tests/encode_unittests.c b/tests/encode_unittests.c
index 3078998..6a8f5e9 100644
--- a/tests/encode_unittests.c
+++ b/tests/encode_unittests.c
@@ -180,12 +180,14 @@ int main()
     {
         uint8_t buffer[30];
         pb_ostream_t s;
-        char value[] = "xyzzy";
+        char value[30] = "xyzzy";
         
         COMMENT("Test pb_enc_string")
-        TEST(WRITES(pb_enc_string(&s, NULL, &value), "\x05xyzzy"))
+        TEST(WRITES(pb_enc_string(&s, &StringMessage_fields[0], &value), "\x05xyzzy"))
         value[0] = '\0';
-        TEST(WRITES(pb_enc_string(&s, NULL, &value), "\x00"))
+        TEST(WRITES(pb_enc_string(&s, &StringMessage_fields[0], &value), "\x00"))
+        memset(value, 'x', 30);
+        TEST(WRITES(pb_enc_string(&s, &StringMessage_fields[0], &value), "\x0Axxxxxxxxxx"))
     }
     
     {
diff --git a/tests/unittestproto.proto b/tests/unittestproto.proto
index c8a39dd..7024942 100644
--- a/tests/unittestproto.proto
+++ b/tests/unittestproto.proto
@@ -8,6 +8,10 @@ message FloatArray {
     repeated float data = 1 [(nanopb).max_count = 10];
 }
 
+message StringMessage {
+    required string data = 1 [(nanopb).max_size = 10];
+}
+
 message CallbackArray {
     // We cheat a bit and use this message for testing other types, too.
     // Nanopb does not care about the actual defined data type for callback