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authorDenys Vlasenko <dvlasenk@redhat.com>2015-04-04 21:55:19 +0300
committerIngo Molnar <mingo@kernel.org>2015-04-06 10:24:08 +0300
commitfc3e958a2b552fe6210e6de3bebb4348156a0b5f (patch)
treefaa91925b07208febff9ad6dcda4dac17f9c9c59 /arch/x86/include/asm/elf.h
parent6a3713f001b3b53587e411ab0d3036ae9b0fb93b (diff)
downloadlinux-fc3e958a2b552fe6210e6de3bebb4348156a0b5f.tar.xz
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>
Diffstat (limited to 'arch/x86/include/asm/elf.h')
-rw-r--r--arch/x86/include/asm/elf.h7
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index ca3347a9dab5..3563107b5060 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -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;