[PATCH 3/8] x86/asm/entry: Zero EXTRA_REGS for stub32_execve[at] too

From: Denys Vlasenko
Date: Tue Apr 07 2015 - 16:44:46 EST

The change which affected how execve clears EXTRA_REGS missed
32-bit execve syscalls.

Fix this by using 64-bit execve stub epilogue for them too.


Signed-off-by: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
CC: Steven Rostedt <rostedt@xxxxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: Borislav Petkov <bp@xxxxxxxxx>
CC: "H. Peter Anvin" <hpa@xxxxxxxxx>
CC: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
CC: Oleg Nesterov <oleg@xxxxxxxxxx>
CC: Frederic Weisbecker <fweisbec@xxxxxxxxx>
CC: Alexei Starovoitov <ast@xxxxxxxxxxxx>
CC: Will Drewry <wad@xxxxxxxxxxxx>
CC: Kees Cook <keescook@xxxxxxxxxxxx>
CC: x86@xxxxxxxxxx
CC: linux-kernel@xxxxxxxxxxxxxxx
arch/x86/ia32/ia32entry.S | 2 --
arch/x86/kernel/entry_64.S | 15 +++++++++++++++
2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 5d8f987..a821b1c 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -571,8 +571,6 @@ GLOBAL(\label)

PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn
PTREGSCALL stub32_sigreturn, sys32_sigreturn
- PTREGSCALL stub32_execve, compat_sys_execve
- PTREGSCALL stub32_execveat, compat_sys_execveat
PTREGSCALL stub32_fork, sys_fork
PTREGSCALL stub32_vfork, sys_vfork

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 1b0793c..8e3ba38 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -461,6 +461,21 @@ ENTRY(stub_x32_execveat)

+ call compat_sys_execve
+ jmp return_from_execve
+ call compat_sys_execveat
+ jmp return_from_execve
* sigreturn is special because it needs to restore all registers on return.
* This cannot be done with SYSRET, so use the IRET return path instead.

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