mirror of https://gitee.com/openkylin/linux.git
x86/asm/entry: Clear EXTRA_REGS for all executable formats
On failure, sys_execve() does not clobber EXTRA_REGS, so we can just return to userpsace without saving/restoring them. On success, ELF_PLAT_INIT() in sys_execve() clears all these registers. On other executable formats: - binfmt_flat.c has similar FLAT_PLAT_INIT, but x86 (and everyone else except sh) doesn't define it. - binfmt_elf_fdpic.c has ELF_FDPIC_PLAT_INIT, but x86 (and most others) doesn't define it. - There are no such hooks in binfmt_aout.c et al. We inherit EXTRA_REGS from the prior executable. This inconsistency was not intended. This change removes SAVE/RESTORE_EXTRA_REGS in stub_execve, removes register clearing in ELF_PLAT_INIT(), and instead simply clears them on success in stub_execve. Run-tested. Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1428173719-7637-1-git-send-email-dvlasenk@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
parent
6a3713f001
commit
fc3e958a2b
|
@ -151,6 +151,15 @@ For 32-bit we have the following conventions - kernel is built with
|
|||
movq_cfi_restore 5*8+\offset, rbx
|
||||
.endm
|
||||
|
||||
.macro ZERO_EXTRA_REGS
|
||||
xorl %r15d, %r15d
|
||||
xorl %r14d, %r14d
|
||||
xorl %r13d, %r13d
|
||||
xorl %r12d, %r12d
|
||||
xorl %ebp, %ebp
|
||||
xorl %ebx, %ebx
|
||||
.endm
|
||||
|
||||
.macro RESTORE_C_REGS_HELPER rstor_rax=1, rstor_rcx=1, rstor_r11=1, rstor_r8910=1, rstor_rdx=1
|
||||
.if \rstor_r11
|
||||
movq_cfi_restore 6*8, r11
|
||||
|
|
|
@ -171,10 +171,11 @@ do { \
|
|||
static inline void elf_common_init(struct thread_struct *t,
|
||||
struct pt_regs *regs, const u16 ds)
|
||||
{
|
||||
regs->ax = regs->bx = regs->cx = regs->dx = 0;
|
||||
regs->si = regs->di = regs->bp = 0;
|
||||
/* Commented-out registers are cleared in stub_execve */
|
||||
/*regs->ax = regs->bx =*/ regs->cx = regs->dx = 0;
|
||||
regs->si = regs->di /*= regs->bp*/ = 0;
|
||||
regs->r8 = regs->r9 = regs->r10 = regs->r11 = 0;
|
||||
regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
|
||||
/*regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;*/
|
||||
t->fs = t->gs = 0;
|
||||
t->fsindex = t->gsindex = 0;
|
||||
t->ds = t->es = ds;
|
||||
|
|
|
@ -419,25 +419,27 @@ END(stub_\func)
|
|||
|
||||
ENTRY(stub_execve)
|
||||
CFI_STARTPROC
|
||||
addq $8, %rsp
|
||||
DEFAULT_FRAME 0
|
||||
SAVE_EXTRA_REGS
|
||||
call sys_execve
|
||||
movq %rax,RAX(%rsp)
|
||||
RESTORE_EXTRA_REGS
|
||||
jmp int_ret_from_sys_call
|
||||
DEFAULT_FRAME 0, 8
|
||||
call sys_execve
|
||||
return_from_execve:
|
||||
testl %eax, %eax
|
||||
jz 1f
|
||||
/* exec failed, can use fast SYSRET code path in this case */
|
||||
ret
|
||||
1:
|
||||
/* must use IRET code path (pt_regs->cs may have changed) */
|
||||
addq $8, %rsp
|
||||
ZERO_EXTRA_REGS
|
||||
movq %rax,RAX(%rsp)
|
||||
jmp int_ret_from_sys_call
|
||||
CFI_ENDPROC
|
||||
END(stub_execve)
|
||||
|
||||
ENTRY(stub_execveat)
|
||||
CFI_STARTPROC
|
||||
addq $8, %rsp
|
||||
DEFAULT_FRAME 0
|
||||
SAVE_EXTRA_REGS
|
||||
call sys_execveat
|
||||
movq %rax,RAX(%rsp)
|
||||
RESTORE_EXTRA_REGS
|
||||
jmp int_ret_from_sys_call
|
||||
DEFAULT_FRAME 0, 8
|
||||
call sys_execveat
|
||||
jmp return_from_execve
|
||||
CFI_ENDPROC
|
||||
END(stub_execveat)
|
||||
|
||||
|
@ -472,25 +474,17 @@ END(stub_x32_rt_sigreturn)
|
|||
|
||||
ENTRY(stub_x32_execve)
|
||||
CFI_STARTPROC
|
||||
addq $8, %rsp
|
||||
DEFAULT_FRAME 0
|
||||
SAVE_EXTRA_REGS
|
||||
call compat_sys_execve
|
||||
movq %rax,RAX(%rsp)
|
||||
RESTORE_EXTRA_REGS
|
||||
jmp int_ret_from_sys_call
|
||||
DEFAULT_FRAME 0, 8
|
||||
call compat_sys_execve
|
||||
jmp return_from_execve
|
||||
CFI_ENDPROC
|
||||
END(stub_x32_execve)
|
||||
|
||||
ENTRY(stub_x32_execveat)
|
||||
CFI_STARTPROC
|
||||
addq $8, %rsp
|
||||
DEFAULT_FRAME 0
|
||||
SAVE_EXTRA_REGS
|
||||
call compat_sys_execveat
|
||||
movq %rax,RAX(%rsp)
|
||||
RESTORE_EXTRA_REGS
|
||||
jmp int_ret_from_sys_call
|
||||
DEFAULT_FRAME 0, 8
|
||||
call compat_sys_execveat
|
||||
jmp return_from_execve
|
||||
CFI_ENDPROC
|
||||
END(stub_x32_execveat)
|
||||
|
||||
|
|
Loading…
Reference in New Issue