* [Buildroot] [Bug 2995] New: -fstack-protector-all causes ssh to SIGSEGV
@ 2010-12-20 15:43 bugzilla at busybox.net
2010-12-20 15:56 ` [Buildroot] [Bug 2995] " bugzilla at busybox.net
` (7 more replies)
0 siblings, 8 replies; 9+ messages in thread
From: bugzilla at busybox.net @ 2010-12-20 15:43 UTC (permalink / raw)
To: buildroot
https://bugs.busybox.net/show_bug.cgi?id=2995
Summary: -fstack-protector-all causes ssh to SIGSEGV
Product: buildroot
Version: unspecified
Platform: PC
OS/Version: Linux
Status: NEW
Severity: normal
Priority: P5
Component: Other
AssignedTo: unassigned at buildroot.uclibc.org
ReportedBy: mario at klebsch.de
CC: buildroot at uclibc.org
Estimated Hours: 0.0
Hi!
I bought an AMD Geode alix 2D13 board and tried to get linux running on it. I
compiled buildroot and from the first attempt on, every ssh program crashes
(SIGSEGV). During booting, ssh-keygen crashes, but the other ssh programs
started on the command line did not run, either.
:-(
To get some light on this, I built gdb for my target system and tried to run
ssh-keygen under debugger control. It turned out, that the SIGSEGV was caused
by the third assembly instruction in main. I added a small 'Hello World' to the
openssh source tree and this program also crashed due to the same cause.
Here is the disassembly of the small hello word (which was compiled to xxx.o):
ds9 src # objdump --disassemble openssh-5.1p1/xxx.o
openssh-5.1p1/xxx.o: file format elf32-i386
Disassembly of section .text:
00000000 <main>:
0: 8d 4c 24 04 lea 0x4(%esp),%ecx
4: 83 e4 f0 and $0xfffffff0,%esp
7: ff 71 fc pushl -0x4(%ecx)
a: 55 push %ebp
b: 89 e5 mov %esp,%ebp
d: 51 push %ecx
e: 83 ec 20 sub $0x20,%esp
11:65 a1 14 00 00 00 mov %gs:0x14,%eax <--- Here it crashed
17:89 45 f8 mov %eax,-0x8(%ebp)
1a: 31 c0 xor %eax,%eax
1c: 68 00 00 00 00 push $0x0
21:e8 fc ff ff ff call 22 <main+0x22>
26:83 c4 10 add $0x10,%esp
29:8b 55 f8 mov -0x8(%ebp),%edx
2c: 65 33 15 14 00 00 00 xor %gs:0x14,%edx
33:75 08 jne 3d <main+0x3d>
35:8b 4d fc mov -0x4(%ebp),%ecx
38:c9 leave
39:8d 61 fc lea -0x4(%ecx),%esp
3c: c3 ret
3d:e8 fc ff ff ff call 3e <main+0x3e>
BTW, the code runs fine on my development system
gdb showed, that the gs register on my target device has a value of 0, while it
is 33 on my development system.
It turned out, that the gcc option -fstack-protector-all, which is used for
openssh, causes the failing instruction to be inserted into the object code.
I have no idea, what the gs register is good for, I was not able to google
information about gs register usage on linux systems. Perhaps, my small linux
kernel is missing some option to initialize this register, perhaps buildroot
has an option to initialize the gs register,...
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* [Buildroot] [Bug 2995] -fstack-protector-all causes ssh to SIGSEGV
2010-12-20 15:43 [Buildroot] [Bug 2995] New: -fstack-protector-all causes ssh to SIGSEGV bugzilla at busybox.net
@ 2010-12-20 15:56 ` bugzilla at busybox.net
2010-12-20 16:52 ` bugzilla at busybox.net
` (6 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: bugzilla at busybox.net @ 2010-12-20 15:56 UTC (permalink / raw)
To: buildroot
https://bugs.busybox.net/show_bug.cgi?id=2995
Peter Korsgaard <jacmet@uclibc.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
--- Comment #1 from Peter Korsgaard <jacmet@uclibc.org> ---
Do you have "Enable stack protection support" (BR2_TOOLCHAIN_BUILDROOT_USE_SSP)
enabled? If yes, do things work if you disable that and do a fresh rebuild
(make clean; make)
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* [Buildroot] [Bug 2995] -fstack-protector-all causes ssh to SIGSEGV
2010-12-20 15:43 [Buildroot] [Bug 2995] New: -fstack-protector-all causes ssh to SIGSEGV bugzilla at busybox.net
2010-12-20 15:56 ` [Buildroot] [Bug 2995] " bugzilla at busybox.net
@ 2010-12-20 16:52 ` bugzilla at busybox.net
2010-12-20 16:56 ` bugzilla at busybox.net
` (5 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: bugzilla at busybox.net @ 2010-12-20 16:52 UTC (permalink / raw)
To: buildroot
https://bugs.busybox.net/show_bug.cgi?id=2995
--- Comment #2 from Mario Klebsch <mario@klebsch.de> ---
(In reply to comment #1)
> Do you have "Enable stack protection support" (BR2_TOOLCHAIN_BUILDROOT_USE_SSP)
> enabled? If yes, do things work if you disable that and do a fresh rebuild
> (make clean; make)
Where can I find this option? I think, I searched all menuconfig branches, but
was unable to find this option. I anso grep'ed all Config.in's for "Enable
stack protection support" and for BR2_TOOLCHAIN_BUILDROOT_USE_SSP, but I cannot
find this entry. :-(
73, Mario
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* [Buildroot] [Bug 2995] -fstack-protector-all causes ssh to SIGSEGV
2010-12-20 15:43 [Buildroot] [Bug 2995] New: -fstack-protector-all causes ssh to SIGSEGV bugzilla at busybox.net
2010-12-20 15:56 ` [Buildroot] [Bug 2995] " bugzilla at busybox.net
2010-12-20 16:52 ` bugzilla at busybox.net
@ 2010-12-20 16:56 ` bugzilla at busybox.net
2010-12-20 21:01 ` bugzilla at busybox.net
` (4 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: bugzilla at busybox.net @ 2010-12-20 16:56 UTC (permalink / raw)
To: buildroot
https://bugs.busybox.net/show_bug.cgi?id=2995
--- Comment #3 from Mario Klebsch <mario@klebsch.de> ---
(In reply to comment #2)
> Where can I find this option? I think, I searched all menuconfig branches, but
> was unable to find this option. I anso grep'ed all Config.in's for "Enable
> stack protection support" and for BR2_TOOLCHAIN_BUILDROOT_USE_SSP, but I cannot
> find this entry. :-(
I finally found it in toolchain/toolchain-buildroot/Config.in.2
The compiler is still running...
73, Mario
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* [Buildroot] [Bug 2995] -fstack-protector-all causes ssh to SIGSEGV
2010-12-20 15:43 [Buildroot] [Bug 2995] New: -fstack-protector-all causes ssh to SIGSEGV bugzilla at busybox.net
` (2 preceding siblings ...)
2010-12-20 16:56 ` bugzilla at busybox.net
@ 2010-12-20 21:01 ` bugzilla at busybox.net
2011-03-02 13:51 ` bugzilla at busybox.net
` (3 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: bugzilla at busybox.net @ 2010-12-20 21:01 UTC (permalink / raw)
To: buildroot
https://bugs.busybox.net/show_bug.cgi?id=2995
--- Comment #4 from Mario Klebsch <mario@klebsch.de> ---
(In reply to comment #1)
> Do you have "Enable stack protection support" (BR2_TOOLCHAIN_BUILDROOT_USE_SSP)
> enabled? If yes, do things work if you disable that and do a fresh rebuild
> (make clean; make)
This option was enabled, and now, after I have disabled this option and rebuild
everything, it seems to work fine.
- Is there an incomaptibility bewteen stack prot4ectiona nd ucLibC or my alix
target system?
- Could it be, that some choosen value in my kernels .config might be the cause
of my trouble?
- Will Buildroot 2010.11 allow me to use stack protection on my target system?
- How does the %gs register fit into this problem? I have learned, that this
register is related to thread local storage, but it is hard to find information
about x86 register usage on linux systems on the web.
73, Mario
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* [Buildroot] [Bug 2995] -fstack-protector-all causes ssh to SIGSEGV
2010-12-20 15:43 [Buildroot] [Bug 2995] New: -fstack-protector-all causes ssh to SIGSEGV bugzilla at busybox.net
` (3 preceding siblings ...)
2010-12-20 21:01 ` bugzilla at busybox.net
@ 2011-03-02 13:51 ` bugzilla at busybox.net
2011-03-02 14:35 ` bugzilla at busybox.net
` (2 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: bugzilla at busybox.net @ 2011-03-02 13:51 UTC (permalink / raw)
To: buildroot
https://bugs.busybox.net/show_bug.cgi?id=2995
--- Comment #5 from Andrew Beard <abeard@wabtec.com> ---
I seem to be having the same problem on a proprietary Geode LX board I'm
working with. I just updated to the 2011.02 and with uclibc 0.9.31 if I enable
stack protection all ssh related executables immediately cause a segfault.
Disabling stack protection seems to alleviate the problem.
One thing I have found is that this problem does not seem to occur with uclibc
09.32-rc2, though. With the new release candidate I can enable or disable
stack protection without causing a problem. At this point we're still trying
to decide if we'd rather continue with a pre-release c library or without stack
protection.
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* [Buildroot] [Bug 2995] -fstack-protector-all causes ssh to SIGSEGV
2010-12-20 15:43 [Buildroot] [Bug 2995] New: -fstack-protector-all causes ssh to SIGSEGV bugzilla at busybox.net
` (4 preceding siblings ...)
2011-03-02 13:51 ` bugzilla at busybox.net
@ 2011-03-02 14:35 ` bugzilla at busybox.net
2011-09-18 10:18 ` bugzilla at busybox.net
2013-11-28 17:15 ` bugzilla at busybox.net
7 siblings, 0 replies; 9+ messages in thread
From: bugzilla at busybox.net @ 2011-03-02 14:35 UTC (permalink / raw)
To: buildroot
https://bugs.busybox.net/show_bug.cgi?id=2995
--- Comment #6 from Thomas Petazzoni <thomas.petazzoni@free-electrons.com> ---
Maybe this should be reported on the uclibc list.
Also the official 0.9.32 should be released fairly soon now, so probably you'll
be able to have *both* an official release and stack protection in your product
:-)
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* [Buildroot] [Bug 2995] -fstack-protector-all causes ssh to SIGSEGV
2010-12-20 15:43 [Buildroot] [Bug 2995] New: -fstack-protector-all causes ssh to SIGSEGV bugzilla at busybox.net
` (5 preceding siblings ...)
2011-03-02 14:35 ` bugzilla at busybox.net
@ 2011-09-18 10:18 ` bugzilla at busybox.net
2013-11-28 17:15 ` bugzilla at busybox.net
7 siblings, 0 replies; 9+ messages in thread
From: bugzilla at busybox.net @ 2011-09-18 10:18 UTC (permalink / raw)
To: buildroot
https://bugs.busybox.net/show_bug.cgi?id=2995
--- Comment #7 from Thomas Petazzoni <thomas.petazzoni@free-electrons.com> ---
Mario, Andrew, any news on this bug ?
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* [Buildroot] [Bug 2995] -fstack-protector-all causes ssh to SIGSEGV
2010-12-20 15:43 [Buildroot] [Bug 2995] New: -fstack-protector-all causes ssh to SIGSEGV bugzilla at busybox.net
` (6 preceding siblings ...)
2011-09-18 10:18 ` bugzilla at busybox.net
@ 2013-11-28 17:15 ` bugzilla at busybox.net
7 siblings, 0 replies; 9+ messages in thread
From: bugzilla at busybox.net @ 2013-11-28 17:15 UTC (permalink / raw)
To: buildroot
https://bugs.busybox.net/show_bug.cgi?id=2995
Gustavo Zacarias <gustavo@zacarias.com.ar> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |WORKSFORME
--- Comment #8 from Gustavo Zacarias <gustavo@zacarias.com.ar> 2013-11-28 17:15:19 UTC ---
I think it's safe to close this bug, i've done testing with stack protection
and openssh and couldn't hit this issue.
Besides it seems to be solved by uclibc 0.9.32+ according to comment #5 and we
don't do 0.9.31 for anything other than avr32 now.
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