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READLINE PATCH REPORT
=====================
Readline-Release: 7.0
Patch-ID: readline70-002
Bug-Reported-by: Hong Cho <hong.cho@citrix.com>
Bug-Reference-ID: <c30b5fe62b2543af8297e47ca487c29c@SJCPEX02CL02.citrite.net>
Bug-Reference-URL: http://lists.gnu.org/archive/html/bug-readline/2016-12/msg00002.html
Bug-Description:
There is a race condition in add_history() that can be triggered by a fatal
signal arriving between the time the history length is updated and the time
the history list update is completed. A later attempt to reference an
invalid history entry can cause a crash.
Index: b/history.c
===================================================================
--- a/history.c
+++ b/history.c
@@ -279,6 +279,7 @@ add_history (string)
const char *string;
{
HIST_ENTRY *temp;
+ int new_length;
if (history_stifled && (history_length == history_max_entries))
{
@@ -295,13 +296,9 @@ add_history (string)
/* Copy the rest of the entries, moving down one slot. Copy includes
trailing NULL. */
-#if 0
- for (i = 0; i < history_length; i++)
- the_history[i] = the_history[i + 1];
-#else
memmove (the_history, the_history + 1, history_length * sizeof (HIST_ENTRY *));
-#endif
+ new_length = history_length;
history_base++;
}
else
@@ -315,7 +312,7 @@ add_history (string)
else
history_size = DEFAULT_HISTORY_INITIAL_SIZE;
the_history = (HIST_ENTRY **)xmalloc (history_size * sizeof (HIST_ENTRY *));
- history_length = 1;
+ new_length = 1;
}
else
{
@@ -325,14 +322,15 @@ add_history (string)
the_history = (HIST_ENTRY **)
xrealloc (the_history, history_size * sizeof (HIST_ENTRY *));
}
- history_length++;
+ new_length = history_length + 1;
}
}
temp = alloc_history_entry ((char *)string, hist_inittime ());
- the_history[history_length] = (HIST_ENTRY *)NULL;
- the_history[history_length - 1] = temp;
+ the_history[new_length] = (HIST_ENTRY *)NULL;
+ the_history[new_length - 1] = temp;
+ history_length = new_length;
}
/* Change the time stamp of the most recent history entry to STRING. */
Index: b/patchlevel
===================================================================
--- a/patchlevel
+++ b/patchlevel
@@ -1,3 +1,3 @@
# Do not edit -- exists only for use by patch
-1
+2
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