From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Urban Date: Tue, 18 May 2010 18:57:12 +0200 Subject: [Buildroot] stack protection support seems not to work? Message-ID: <4BF2C6E8.8070702@unix-beratung.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Hi Folks, in my environment, which I git cloned yesterday, turning on stack protection (BR2_USE_SSP) seems to break openssh (and probably anything else that is compiled with it). When trying to run ssh/scp/ssh-agent/sftp on target, I get something like: ssh[2842] general protection ip:804c375 sp:afa542b0 error:0 in ssh[8048000+3b000] With some help from an expert, we traced the error, sort-of. It's generated in main(), very near the beginning. Here's an excerpt from "buildroot-env/objdump -d ssh.o": 0000040e
: 40e: 8d 4c 24 04 lea 0x4(%esp),%ecx 412: 83 e4 f0 and $0xfffffff0,%esp 415: ff 71 fc pushl -0x4(%ecx) 418: 55 push %ebp 419: 89 e5 mov %esp,%ebp 41b: 57 push %edi 41c: 56 push %esi 41d: 53 push %ebx 41e: 51 push %ecx 41f: 81 ec d8 05 00 00 sub $0x5d8,%esp 425: 65 8b 15 14 00 00 00 mov %gs:0x14,%edx 42c: 89 55 ec mov %edx,-0x14(%ebp) 42f: 31 d2 xor %edx,%edx 431: 8b 01 mov (%ecx),%eax 433: 8b 71 04 mov 0x4(%ecx),%esi 436: 89 85 2c fa ff ff mov %eax,-0x5d4(%ebp) 43c: e8 fc ff ff ff call 43d 441: 83 ec 0c sub $0xc,%esp 444: ff 36 pushl (%esi) The error probably originates from the instructions at offset 425 mov %gs:0x14,%edx "%gs", whatever that may be, seems uninitialized. ARCH is i386, CPU is i586. if anyone cares, mail me for config and/or build log. Rob Urban