From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: mhiramat@kernel.org, linux-kernel@vger.kernel.org,
Andy Lutomirski <luto@amacapital.net>,
Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Changbin Du <changbin.du@gmail.com>, Jann Horn <jannh@google.com>,
Kees Cook <keescook@chromium.org>,
Andy Lutomirski <luto@kernel.org>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Nadav Amit <namit@vmware.com>,
Peter Zijlstra <peterz@infradead.org>
Subject: [PATCH v3 1/5] uaccess: Add user_access_ok()
Date: Wed, 27 Feb 2019 23:42:45 +0900 [thread overview]
Message-ID: <155127856505.32576.15793078010764401547.stgit@devbox> (raw)
In-Reply-To: <155127853496.32576.3705994926675037747.stgit@devbox>
From: Peter Zijlstra <peterz@infradead.org>
Add user_access_ok() macro which ensures current context
is user context, or explicitly do set_fs(USER_DS).
This function is very much like access_ok(), except it (may)
have different context validation. In general we must be
very careful when using this.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
arch/x86/include/asm/uaccess.h | 8 +++++++-
include/linux/uaccess.h | 18 ++++++++++++++++++
2 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 780f2b42c8ef..3125d129d3b6 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -92,12 +92,18 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un
* checks that the pointer is in the user space range - after calling
* this function, memory access functions may still return -EFAULT.
*/
-#define access_ok(addr, size) \
+#define access_ok(addr, size) \
({ \
WARN_ON_IN_IRQ(); \
likely(!__range_not_ok(addr, size, user_addr_max())); \
})
+#define user_access_ok(addr, size) \
+({ \
+ WARN_ON_ONCE(!segment_eq(get_fs(), USER_DS)); \
+ likely(!__range_not_ok(addr, size, user_addr_max())); \
+})
+
/*
* These are the main single-value transfer routines. They automatically
* use the right size if we just have the right pointer type.
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 37b226e8df13..bf762689658b 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -10,6 +10,24 @@
#include <asm/uaccess.h>
+/**
+ * user_access_ok: Checks if a user space pointer is valid
+ * @addr: User space pointer to start of block to check
+ * @size: Size of block to check
+ *
+ * Context: User context or explicit set_fs(USER_DS).
+ *
+ * This function is very much like access_ok(), except it (may) have different
+ * context validation. In general we must be very careful when using this.
+ */
+#ifndef user_access_ok
+#define user_access_ok(addr, size) \
+({ \
+ WARN_ON_ONCE(!segment_eq(get_fs(), USER_DS)); \
+ access_ok(addr, size); \
+})
+#endif
+
/*
* Architectures should provide two primitives (raw_copy_{to,from}_user())
* and get rid of their private instances of copy_{to,from}_user() and
next prev parent reply other threads:[~2019-02-27 14:43 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-27 14:42 [PATCH v3 0/5] tracing/probes: uaccess: Add support user-space access Masami Hiramatsu
2019-02-27 14:42 ` Masami Hiramatsu [this message]
2019-02-27 14:43 ` [PATCH v3 2/5] uaccess: Use user_access_ok() in user_access_begin() Masami Hiramatsu
2019-02-27 14:43 ` [PATCH v3 3/5] uaccess: Add non-pagefault user-space read functions Masami Hiramatsu
2019-02-27 14:44 ` [PATCH v3 4/5] tracing/probe: Add ustring type for user-space string Masami Hiramatsu
2019-02-28 2:20 ` Steven Rostedt
2019-02-27 14:44 ` [PATCH v3 5/5] tracing/probe: Support user-space dereference Masami Hiramatsu
2019-02-28 2:31 ` Steven Rostedt
2019-02-28 7:00 ` Masami Hiramatsu
2019-02-28 16:20 ` Steven Rostedt
2019-02-28 2:42 ` Steven Rostedt
2019-02-28 6:08 ` Masami Hiramatsu
2019-02-27 22:32 ` [PATCH v3 0/5] tracing/probes: uaccess: Add support user-space access Alexei Starovoitov
2019-02-28 1:54 ` Masami Hiramatsu
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