>Number: 146167
>Category: kern
>Synopsis: ptrace PT_DETACH undocumented behavior
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Apr 30 02:10:01 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator: Gunnar Hinriksson
>Release: 8.0-RELEASE-p2
>Organization:
>Environment:
FreeBSD knut 8.0-RELEASE-p2 FreeBSD 8.0-RELEASE-p2 #0: Tue Apr 27 04:36:16 UTC
2010 gun...@knut:/usr/obj/usr/src/sys/GENERIC amd64
>Description:
When using PT_DETACH on ptrace the (caddr_t addr) parameter is not ignored like
the documentation suggests.
Instead it proceeds to change the execution address to the value of the
parameter if it is not (void *)1.
This can cause portability problems from other systems that implement ptrace
and assume that the parameter is ignored.
>How-To-Repeat:
Write a program that uses ptrace to attach to another process and then detach
with the parameter (caddr_t addr) value not equal to 1.
This can cause the child process to segfault.
>Fix:
Attached patch.
Patch attached with submission follows:
--- /usr/src/sys/kern/sys_process.c 2009-10-25 01:10:29.000000000 +0000
+++ sys_process.c 2010-04-30 01:32:52.507274805 +0000
@@ -741,10 +741,13 @@
break;
}
- if (addr != (void *)1) {
- error = ptrace_set_pc(td2, (u_long)(uintfptr_t)addr);
- if (error)
- break;
+ if (req == PT_CONTINUE)
+ {
+ if (addr != (void *)1) {
+ error = ptrace_set_pc(td2,
(u_long)(uintfptr_t)addr);
+ if (error)
+ break;
+ }
}
if (req == PT_DETACH) {
>Release-Note:
>Audit-Trail:
>Unformatted:
_______________________________________________
[email protected] mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-bugs
To unsubscribe, send any mail to "[email protected]"
