[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-Id: <20170814213732.104301-1-thgarnie@google.com>
Date: Mon, 14 Aug 2017 14:37:29 -0700
From: Thomas Garnier <thgarnie@...gle.com>
To: Al Viro <viro@...iv.linux.org.uk>,
Dave Hansen <dave.hansen@...el.com>,
Arnd Bergmann <arnd@...db.de>,
Thomas Gleixner <tglx@...utronix.de>,
Thomas Garnier <thgarnie@...gle.com>,
Yonghong Song <yhs@...com>,
David Howells <dhowells@...hat.com>,
Russell King <linux@...linux.org.uk>,
Kees Cook <keescook@...omium.org>,
Andy Lutomirski <luto@...capital.net>,
Will Drewry <wad@...omium.org>,
Dave Martin <Dave.Martin@....com>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>
Cc: linux-api@...r.kernel.org,
linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
kernel-hardening@...ts.openwall.com
Subject: [PATCH v3 1/4] syscalls: Use CHECK_DATA_CORRUPTION for addr_limit_user_check
Use CHECK_DATA_CORRUPTION instead of BUG_ON to provide more flexibility
on address limit failures. By default, send a SIGKILL signal to kill the
current process preventing exploitation of a bad address limit.
Make the TIF_FSCHECK flag optional so ARM can use this function.
Signed-off-by: Thomas Garnier <thgarnie@...gle.com>
---
include/linux/syscalls.h | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 88951b795ee3..65e273aadada 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -219,21 +219,25 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event)
} \
static inline long SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__))
-#ifdef TIF_FSCHECK
/*
* Called before coming back to user-mode. Returning to user-mode with an
* address limit different than USER_DS can allow to overwrite kernel memory.
*/
static inline void addr_limit_user_check(void)
{
-
+#ifdef TIF_FSCHECK
if (!test_thread_flag(TIF_FSCHECK))
return;
+#endif
- BUG_ON(!segment_eq(get_fs(), USER_DS));
+ if (CHECK_DATA_CORRUPTION(!segment_eq(get_fs(), USER_DS),
+ "Invalid address limit on user-mode return"))
+ force_sig(SIGKILL, current);
+
+#ifdef TIF_FSCHECK
clear_thread_flag(TIF_FSCHECK);
-}
#endif
+}
asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
qid_t id, void __user *addr);
--
2.14.1.480.gb18f417b89-goog
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
