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| author | Peter Zijlstra <peterz@infradead.org> | 2019-02-25 12:56:35 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-06-11 12:24:03 +0200 |
| commit | 5680f59f0f151ff22faa1351f15f0d0351266e71 (patch) | |
| tree | e24fe6d6344568c7ed30407b9b24f7a3b8e95e01 | |
| parent | 94032b2e05c94e7d6babd438b2341c1510c213ee (diff) | |
| download | linux-stable-5680f59f0f151ff22faa1351f15f0d0351266e71.tar.gz linux-stable-5680f59f0f151ff22faa1351f15f0d0351266e71.tar.bz2 linux-stable-5680f59f0f151ff22faa1351f15f0d0351266e71.zip | |
x86/ia32: Fix ia32_restore_sigcontext() AC leak
[ Upstream commit 67a0514afdbb8b2fc70b771b8c77661a9cb9d3a9 ]
Objtool spotted that we call native_load_gs_index() with AC set.
Re-arrange the code to avoid that.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | arch/x86/ia32/ia32_signal.c | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c index 0552884da18d..a7b9acd709db 100644 --- a/arch/x86/ia32/ia32_signal.c +++ b/arch/x86/ia32/ia32_signal.c @@ -60,9 +60,8 @@ } while (0) #define RELOAD_SEG(seg) { \ - unsigned int pre = GET_SEG(seg); \ + unsigned int pre = (seg) | 3; \ unsigned int cur = get_user_seg(seg); \ - pre |= 3; \ if (pre != cur) \ set_user_seg(seg, pre); \ } @@ -71,6 +70,7 @@ static int ia32_restore_sigcontext(struct pt_regs *regs, struct sigcontext_32 __user *sc) { unsigned int tmpflags, err = 0; + u16 gs, fs, es, ds; void __user *buf; u32 tmp; @@ -78,16 +78,10 @@ static int ia32_restore_sigcontext(struct pt_regs *regs, current->restart_block.fn = do_no_restart_syscall; get_user_try { - /* - * Reload fs and gs if they have changed in the signal - * handler. This does not handle long fs/gs base changes in - * the handler, but does not clobber them at least in the - * normal case. - */ - RELOAD_SEG(gs); - RELOAD_SEG(fs); - RELOAD_SEG(ds); - RELOAD_SEG(es); + gs = GET_SEG(gs); + fs = GET_SEG(fs); + ds = GET_SEG(ds); + es = GET_SEG(es); COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx); COPY(dx); COPY(cx); COPY(ip); COPY(ax); @@ -105,6 +99,17 @@ static int ia32_restore_sigcontext(struct pt_regs *regs, buf = compat_ptr(tmp); } get_user_catch(err); + /* + * Reload fs and gs if they have changed in the signal + * handler. This does not handle long fs/gs base changes in + * the handler, but does not clobber them at least in the + * normal case. + */ + RELOAD_SEG(gs); + RELOAD_SEG(fs); + RELOAD_SEG(ds); + RELOAD_SEG(es); + err |= fpu__restore_sig(buf, 1); force_iret(); |