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authorAlexander Potapenko <glider@google.com>2022-09-15 17:03:37 +0200
committerAndrew Morton <akpm@linux-foundation.org>2022-10-03 14:03:18 -0700
commit33b75c1d884e81ec97525e0a6fdcb187adf273f4 (patch)
treea3bc5340b6e3a95024c7a342f4d522835f437c0a
parent83a4f1ef45a90d740bc6edf6a2533b14a3e5d183 (diff)
instrumented.h: allow instrumenting both sides of copy_from_user()
Introduce instrument_copy_from_user_before() and instrument_copy_from_user_after() hooks to be invoked before and after the call to copy_from_user(). KASAN and KCSAN will be only using instrument_copy_from_user_before(), but for KMSAN we'll need to insert code after copy_from_user(). Link: https://lkml.kernel.org/r/20220915150417.722975-4-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Eric Biggers <ebiggers@kernel.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Ilya Leoshkevich <iii@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--arch/s390/lib/uaccess.c3
-rw-r--r--include/linux/instrumented.h21
-rw-r--r--include/linux/uaccess.h19
-rw-r--r--lib/iov_iter.c9
-rw-r--r--lib/usercopy.c3
5 files changed, 43 insertions, 12 deletions
diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c
index d7b3b193d108..58033dfcb6d4 100644
--- a/arch/s390/lib/uaccess.c
+++ b/arch/s390/lib/uaccess.c
@@ -81,8 +81,9 @@ unsigned long _copy_from_user_key(void *to, const void __user *from,
might_fault();
if (!should_fail_usercopy()) {
- instrument_copy_from_user(to, from, n);
+ instrument_copy_from_user_before(to, from, n);
res = raw_copy_from_user_key(to, from, n, key);
+ instrument_copy_from_user_after(to, from, n, res);
}
if (unlikely(res))
memset(to + (n - res), 0, res);
diff --git a/include/linux/instrumented.h b/include/linux/instrumented.h
index 42faebbaa202..ee8f7d17d34f 100644
--- a/include/linux/instrumented.h
+++ b/include/linux/instrumented.h
@@ -120,7 +120,7 @@ instrument_copy_to_user(void __user *to, const void *from, unsigned long n)
}
/**
- * instrument_copy_from_user - instrument writes of copy_from_user
+ * instrument_copy_from_user_before - add instrumentation before copy_from_user
*
* Instrument writes to kernel memory, that are due to copy_from_user (and
* variants). The instrumentation should be inserted before the accesses.
@@ -130,10 +130,27 @@ instrument_copy_to_user(void __user *to, const void *from, unsigned long n)
* @n number of bytes to copy
*/
static __always_inline void
-instrument_copy_from_user(const void *to, const void __user *from, unsigned long n)
+instrument_copy_from_user_before(const void *to, const void __user *from, unsigned long n)
{
kasan_check_write(to, n);
kcsan_check_write(to, n);
}
+/**
+ * instrument_copy_from_user_after - add instrumentation after copy_from_user
+ *
+ * Instrument writes to kernel memory, that are due to copy_from_user (and
+ * variants). The instrumentation should be inserted after the accesses.
+ *
+ * @to destination address
+ * @from source address
+ * @n number of bytes to copy
+ * @left number of bytes not copied (as returned by copy_from_user)
+ */
+static __always_inline void
+instrument_copy_from_user_after(const void *to, const void __user *from,
+ unsigned long n, unsigned long left)
+{
+}
+
#endif /* _LINUX_INSTRUMENTED_H */
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 47e5d374c7eb..afb18f198843 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -58,20 +58,28 @@
static __always_inline __must_check unsigned long
__copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
{
- instrument_copy_from_user(to, from, n);
+ unsigned long res;
+
+ instrument_copy_from_user_before(to, from, n);
check_object_size(to, n, false);
- return raw_copy_from_user(to, from, n);
+ res = raw_copy_from_user(to, from, n);
+ instrument_copy_from_user_after(to, from, n, res);
+ return res;
}
static __always_inline __must_check unsigned long
__copy_from_user(void *to, const void __user *from, unsigned long n)
{
+ unsigned long res;
+
might_fault();
+ instrument_copy_from_user_before(to, from, n);
if (should_fail_usercopy())
return n;
- instrument_copy_from_user(to, from, n);
check_object_size(to, n, false);
- return raw_copy_from_user(to, from, n);
+ res = raw_copy_from_user(to, from, n);
+ instrument_copy_from_user_after(to, from, n, res);
+ return res;
}
/**
@@ -115,8 +123,9 @@ _copy_from_user(void *to, const void __user *from, unsigned long n)
unsigned long res = n;
might_fault();
if (!should_fail_usercopy() && likely(access_ok(from, n))) {
- instrument_copy_from_user(to, from, n);
+ instrument_copy_from_user_before(to, from, n);
res = raw_copy_from_user(to, from, n);
+ instrument_copy_from_user_after(to, from, n, res);
}
if (unlikely(res))
memset(to + (n - res), 0, res);
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 4b7fce72e3e5..c3ca28ca68a6 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -174,13 +174,16 @@ static int copyout(void __user *to, const void *from, size_t n)
static int copyin(void *to, const void __user *from, size_t n)
{
+ size_t res = n;
+
if (should_fail_usercopy())
return n;
if (access_ok(from, n)) {
- instrument_copy_from_user(to, from, n);
- n = raw_copy_from_user(to, from, n);
+ instrument_copy_from_user_before(to, from, n);
+ res = raw_copy_from_user(to, from, n);
+ instrument_copy_from_user_after(to, from, n, res);
}
- return n;
+ return res;
}
static inline struct pipe_buffer *pipe_buf(const struct pipe_inode_info *pipe,
diff --git a/lib/usercopy.c b/lib/usercopy.c
index 7413dd300516..1505a52f23a0 100644
--- a/lib/usercopy.c
+++ b/lib/usercopy.c
@@ -12,8 +12,9 @@ unsigned long _copy_from_user(void *to, const void __user *from, unsigned long n
unsigned long res = n;
might_fault();
if (!should_fail_usercopy() && likely(access_ok(from, n))) {
- instrument_copy_from_user(to, from, n);
+ instrument_copy_from_user_before(to, from, n);
res = raw_copy_from_user(to, from, n);
+ instrument_copy_from_user_after(to, from, n, res);
}
if (unlikely(res))
memset(to + (n - res), 0, res);