(read_process_output): While processing carryover,

check the size of p->decoding_buf.

diff --git a/src/process.c b/src/process.c
index 814fbc4..d76cebe 100644 (file)
--- a/src/process.c
+++ b/src/process.c
@@ -2855,13 +2855,19 @@ read_process_output (proc, channel)
       carryover = nbytes - coding->consumed;
       if (carryover > 0)
        {
-         /* We must move the data carried over to the tail of
-            decoding buffer.  We are sure that the size of decoding
-            buffer (decided by decoding_buffer_size) is large enough
-            to contain them.  */
-         bcopy (chars + nbytes - carryover,
-                (XSTRING (p->decoding_buf)->data
-                 + STRING_BYTES (XSTRING (p->decoding_buf)) - carryover),
+         /* Copy the carryover bytes to the end of p->decoding_buf, to
+            be processed on the next read.  Since decoding_buffer_size
+            asks for an extra amount of space beyond the maximum
+            expected for the output, there should always be sufficient
+            space for the carryover (which is by definition a sequence
+            of bytes that was not long enough to be decoded, and thus
+            has a bounded length).  */
+         if (STRING_BYTES (XSTRING (p->decoding_buf))
+             < coding->produced + carryover)
+           abort ();
+         bcopy (chars + coding->consumed,
+                XSTRING (p->decoding_buf)->data
+                + STRING_BYTES (XSTRING (p->decoding_buf)) - carryover,
                 carryover);
          XSETINT (p->decoding_carryover, carryover);
        }