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BASH PATCH REPORT
=================
Bash-Release: 4.4
Patch-ID: bash44-009
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-bash/2016-12/msg00043.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.
Patch (apply with `patch -p0'):
*** ../bash-4.4-patched/lib/readline/history.c 2016-11-11 13:42:49.000000000 -0500
--- lib/readline/history.c 2016-12-05 10:37:51.000000000 -0500
***************
*** 280,283 ****
--- 280,284 ----
{
HIST_ENTRY *temp;
+ int new_length;
if (history_stifled && (history_length == history_max_entries))
***************
*** 296,306 ****
/* 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
history_base++;
}
--- 297,303 ----
/* Copy the rest of the entries, moving down one slot. Copy includes
trailing NULL. */
memmove (the_history, the_history + 1, history_length * sizeof (HIST_ENTRY *));
+ new_length = history_length;
history_base++;
}
***************
*** 316,320 ****
history_size = DEFAULT_HISTORY_INITIAL_SIZE;
the_history = (HIST_ENTRY **)xmalloc (history_size * sizeof (HIST_ENTRY *));
! history_length = 1;
}
else
--- 313,317 ----
history_size = DEFAULT_HISTORY_INITIAL_SIZE;
the_history = (HIST_ENTRY **)xmalloc (history_size * sizeof (HIST_ENTRY *));
! new_length = 1;
}
else
***************
*** 326,330 ****
xrealloc (the_history, history_size * sizeof (HIST_ENTRY *));
}
! history_length++;
}
}
--- 323,327 ----
xrealloc (the_history, history_size * sizeof (HIST_ENTRY *));
}
! new_length = history_length + 1;
}
}
***************
*** 332,337 ****
temp = alloc_history_entry ((char *)string, hist_inittime ());
! the_history[history_length] = (HIST_ENTRY *)NULL;
! the_history[history_length - 1] = temp;
}
--- 329,335 ----
temp = alloc_history_entry ((char *)string, hist_inittime ());
! the_history[new_length] = (HIST_ENTRY *)NULL;
! the_history[new_length - 1] = temp;
! history_length = new_length;
}
*** ../bash-4.4/patchlevel.h 2016-06-22 14:51:03.000000000 -0400
--- patchlevel.h 2016-10-01 11:01:28.000000000 -0400
***************
*** 26,30 ****
looks for to find the patch level (for the sccs version string). */
! #define PATCHLEVEL 8
#endif /* _PATCHLEVEL_H_ */
--- 26,30 ----
looks for to find the patch level (for the sccs version string). */
! #define PATCHLEVEL 9
#endif /* _PATCHLEVEL_H_ */
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