ports/80755: uim segmentation fault

[YONETANI Tomokazu]

>Number:         80755
>Category:       ports
>Synopsis:       uim segmentation fault
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    freebsd-ports-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun May 08 11:40:02 GMT 2005
>Closed-Date:
>Last-Modified:
>Originator:     YONETANI Tomokazu
>Release:        FreeBSD 4.11-RELEASE
>Organization:
>Environment:
>Description:
uim-0.4.6 (japanese/uim port) has incorrect use of bind_textdomain_codeset()
in its macro definition in uim/context.h . The macros in question are
as follows:

UIM_SWITCH_TEXTDOMAIN_CODESET
UIM_RESTORE_TEXTDOMAIN_CODESET

The former calls bind_textdomain_codeset() to get the current codeset
and set it to a local pointer orig_encoding (defined by another macro),
then call bind_textdomain_codeset() to set the new codeset for the specified
textdomain. The latter restores the previous codeset for the textdomain
by calling bind_textdomain_codeset() with orig_encoding as its argument.

According to the man page of bind_textdomain_codeset() function,
the return value is valid until the next call to the same function.
That is, the original codeset pointed to by orig_encoding is no longer
valid by the time UIM_RESTORE_TEXTDOMAIN_CODESET is used. This sometimes
results in referencing a free'ed memory location and segmentation fault,
because the private function set_binding_values() frees the previously
handed out string before registering the new codeset string.
>How-To-Repeat:
Install mlterm with WITH_UIM=yes, and turn on uim from the configuration
panel, and type in a few keystrokes.
>Fix:
Drop in the following patch into files/ directory.
(also available at http://les.ath.cx/patches/patch-uim-context.h)

--- uim/context.h.orig	2005-02-05 11:50:05.000000000 +0900
+++ uim/context.h	2005-05-08 20:07:28.000000000 +0900
@@ -156,13 +156,18 @@
 
 #ifdef ENABLE_NLS
 #define UIM_PREPARE_SAVING_TEXTDOMAIN_CODESET() \
-    const char *orig_encoding, *client_encoding;
+    char *orig_encoding; \
+    const char *client_encoding;
 #define UIM_SWITCH_TEXTDOMAIN_CODESET(uc) \
   orig_encoding = bind_textdomain_codeset(GETTEXT_PACKAGE, NULL); \
+  if (orig_encoding != NULL) \
+    orig_encoding = strdup(orig_encoding); \
   client_encoding = (uc) ? ((struct uim_context_ *)uc)->encoding : uim_last_client_encoding; \
   bind_textdomain_codeset(GETTEXT_PACKAGE, client_encoding);
 #define UIM_RESTORE_TEXTDOMAIN_CODESET() \
-  bind_textdomain_codeset(GETTEXT_PACKAGE, orig_encoding);
+  bind_textdomain_codeset(GETTEXT_PACKAGE, orig_encoding); \
+  if (orig_encoding != NULL) \
+    free(orig_encoding);
 #else  /* ENABLE_NLS */
 #define UIM_PREPARE_SAVING_TEXTDOMAIN_CODESET()
 #define UIM_SWITCH_TEXTDOMAIN_CODESET(uc)
>Release-Note:
>Audit-Trail:
>Unformatted: