| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <cover.1405095200.git.luto@amacapital.net> Date: Fri, 11 Jul 2014 09:29:21 -0700 From: Andy Lutomirski <luto@...capital.net> To: "H. Peter Anvin" <hpa@...or.com>, Andi Kleen <andi@...stfloor.org> Cc: Al Viro <viro@...IV.linux.org.uk>, x86@...nel.org, linux-kernel@...r.kernel.org, Andy Lutomirski <luto@...capital.net> Subject: [PATCH 0/2] x86_64,signal: Fix the set of saved segment registers The x86_64 signal code claims to save and restore CS, FS, and GS, and it further claims that this is the minimal set that's needed. Neither of these claims is true. The code does not, and AFAICT never has, saved or restored FS and GS, nor does it need to. On the other hand, all 64-bit syscalls (and rt_sigreturn in particular) clobber SS, making it impossible for signal handlers to correctly restore SS without using a trampoline or ptracing themselves. This patchset saves and restores SS in the __pad0 slot and renames the FS and GS slots __pad1 and __pad2 to more accurately document their purpose. I discovered this while writing a test for espfix64. Andy Lutomirski (2): x86_64,signal: Save and restore SS in signal frames x86_64,signal: Remove 'fs' and 'gs' from sigcontext arch/x86/include/asm/sigcontext.h | 6 +++--- arch/x86/include/uapi/asm/sigcontext.h | 6 +++--- arch/x86/kernel/signal.c | 12 +++--------- 3 files changed, 9 insertions(+), 15 deletions(-) -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists