From: Josh Poimboeuf <jpoimboe@redhat.com>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Nick Desaulniers <ndesaulniers@google.com>,
Arnd Bergmann <arnd@arndb.de>, Jann Horn <jannh@google.com>,
Randy Dunlap <rdunlap@infradead.org>
Subject: [PATCH 08/22] x86/uaccess: Don't leak AC flag into fentry from mcsafe_handle_tail()
Date: Sun, 14 Jul 2019 19:37:03 -0500 [thread overview]
Message-ID: <8353611be174db8d510c890e081bb5e1133b73e3.1563150885.git.jpoimboe@redhat.com> (raw)
In-Reply-To: <cover.1563150885.git.jpoimboe@redhat.com>
After adding mcsafe_handle_tail() to the objtool uaccess safe list,
objtool reports:
arch/x86/lib/usercopy_64.o: warning: objtool: mcsafe_handle_tail()+0x0: call to __fentry__() with UACCESS enabled
With SMAP, this function is called with AC=1, so it needs to be careful
about which functions it calls. Disable the ftrace entry hook, which
can potentially pull in a lot of extra code.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
arch/x86/lib/usercopy_64.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c
index e0e006f1624e..fff28c6f73a2 100644
--- a/arch/x86/lib/usercopy_64.c
+++ b/arch/x86/lib/usercopy_64.c
@@ -60,7 +60,7 @@ EXPORT_SYMBOL(clear_user);
* but reuse __memcpy_mcsafe in case a new read error is encountered.
* clac() is handled in _copy_to_iter_mcsafe().
*/
-__visible unsigned long
+__visible notrace unsigned long
mcsafe_handle_tail(char *to, char *from, unsigned len)
{
for (; len; --len, to++, from++) {
--
2.20.1
next prev parent reply other threads:[~2019-07-15 0:38 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-15 0:36 [PATCH 00/22] x86, objtool: several fixes/improvements Josh Poimboeuf
2019-07-15 0:36 ` [PATCH 01/22] x86/paravirt: Fix callee-saved function ELF sizes Josh Poimboeuf
2019-07-15 4:58 ` Juergen Gross
2019-07-15 12:43 ` Josh Poimboeuf
2019-07-15 0:36 ` [PATCH 02/22] x86/kvm: Fix fastop function ELF metadata Josh Poimboeuf
2019-07-15 9:05 ` Paolo Bonzini
2019-07-15 0:36 ` [PATCH 03/22] x86/kvm: Fix frame pointer usage in vmx_vmenter() Josh Poimboeuf
2019-07-15 9:04 ` Paolo Bonzini
2019-07-15 12:37 ` Josh Poimboeuf
2019-07-15 13:03 ` Paolo Bonzini
2019-07-15 13:35 ` Josh Poimboeuf
2019-07-15 18:17 ` Paolo Bonzini
2019-07-15 0:36 ` [PATCH 04/22] x86/kvm: Don't call kvm_spurious_fault() from .fixup Josh Poimboeuf
2019-07-15 9:07 ` Paolo Bonzini
2019-07-15 12:40 ` Josh Poimboeuf
2019-07-15 13:05 ` Paolo Bonzini
2019-07-15 13:25 ` Josh Poimboeuf
2019-07-15 18:16 ` Paolo Bonzini
2019-07-15 0:37 ` [PATCH 05/22] x86/entry: Fix thunk function ELF sizes Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 06/22] x86/head/64: Annotate start_cpu0() as non-callable Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 07/22] x86/uaccess: Remove ELF function annotation from copy_user_handle_tail() Josh Poimboeuf
2019-07-16 18:16 ` Nick Desaulniers
2019-07-16 18:51 ` Peter Zijlstra
2019-07-15 0:37 ` Josh Poimboeuf [this message]
2019-07-15 0:37 ` [PATCH 09/22] x86/uaccess: Remove redundant CLACs in getuser/putuser error paths Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 10/22] bpf: Disable GCC -fgcse optimization for ___bpf_prog_run() Josh Poimboeuf
2019-07-16 18:15 ` Nick Desaulniers
2019-07-16 23:02 ` Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 11/22] objtool: Add mcsafe_handle_tail() to the uaccess safe list Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 12/22] objtool: Track original function across branches Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 13/22] objtool: Refactor function alias logic Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 14/22] objtool: Warn on zero-length functions Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 15/22] objtool: Change dead_end_function() to return boolean Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 16/22] objtool: Do frame pointer check before dead end check Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 17/22] objtool: Refactor sibling call detection logic Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 18/22] objtool: Refactor jump table code Josh Poimboeuf
2019-07-15 9:38 ` Peter Zijlstra
2019-07-15 0:37 ` [PATCH 19/22] objtool: Support repeated uses of the same C jump table Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 20/22] objtool: Fix seg fault on bad switch table entry Josh Poimboeuf
2019-07-15 17:24 ` Nick Desaulniers
2019-07-15 17:29 ` Josh Poimboeuf
2019-07-18 23:02 ` Nick Desaulniers
2019-07-15 0:37 ` [PATCH 21/22] objtool: convert insn type to enum Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 22/22] objtool: Support conditional retpolines Josh Poimboeuf
2019-07-15 9:52 ` [PATCH 00/22] x86, objtool: several fixes/improvements Peter Zijlstra
2019-07-15 19:38 ` Josh Poimboeuf
2019-07-15 21:45 ` Nick Desaulniers
2019-07-16 23:17 ` Josh Poimboeuf
2019-07-18 22:26 ` Nick Desaulniers
2019-09-27 20:24 ` Nick Desaulniers
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