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authorAlbert van der Linde <alinde@google.com>2020-10-15 20:13:50 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-16 11:11:22 -0700
commit4d0e9df5e43dba52d38b251e3b909df8fa1110be (patch)
tree6132ad46be683778740f7144820f465725a1b90e /lib
parent2c739ced5886cd8c8361faa79a9522ec05174ed0 (diff)
downloadlwn-4d0e9df5e43dba52d38b251e3b909df8fa1110be.tar.gz
lwn-4d0e9df5e43dba52d38b251e3b909df8fa1110be.zip
lib, uaccess: add failure injection to usercopy functions
To test fault-tolerance of user memory access functions, introduce fault injection to usercopy functions. If a failure is expected return either -EFAULT or the total amount of bytes that were not copied. Signed-off-by: Albert van der Linde <alinde@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Marco Elver <elver@google.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Christoph Hellwig <hch@lst.de> Link: http://lkml.kernel.org/r/20200831171733.955393-3-alinde@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/iov_iter.c5
-rw-r--r--lib/strncpy_from_user.c3
-rw-r--r--lib/usercopy.c5
3 files changed, 12 insertions, 1 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 14cae2584db4..1635111c5bd2 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -2,6 +2,7 @@
#include <crypto/hash.h>
#include <linux/export.h>
#include <linux/bvec.h>
+#include <linux/fault-inject-usercopy.h>
#include <linux/uio.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
@@ -140,6 +141,8 @@
static int copyout(void __user *to, const void *from, size_t n)
{
+ if (should_fail_usercopy())
+ return n;
if (access_ok(to, n)) {
instrument_copy_to_user(to, from, n);
n = raw_copy_to_user(to, from, n);
@@ -149,6 +152,8 @@ static int copyout(void __user *to, const void *from, size_t n)
static int copyin(void *to, const void __user *from, size_t 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);
diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c
index 34696a348864..e6d5fcc2cdf3 100644
--- a/lib/strncpy_from_user.c
+++ b/lib/strncpy_from_user.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/compiler.h>
#include <linux/export.h>
+#include <linux/fault-inject-usercopy.h>
#include <linux/kasan-checks.h>
#include <linux/thread_info.h>
#include <linux/uaccess.h>
@@ -99,6 +100,8 @@ long strncpy_from_user(char *dst, const char __user *src, long count)
unsigned long max_addr, src_addr;
might_fault();
+ if (should_fail_usercopy())
+ return -EFAULT;
if (unlikely(count <= 0))
return 0;
diff --git a/lib/usercopy.c b/lib/usercopy.c
index b26509f112f9..7413dd300516 100644
--- a/lib/usercopy.c
+++ b/lib/usercopy.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/bitops.h>
+#include <linux/fault-inject-usercopy.h>
#include <linux/instrumented.h>
#include <linux/uaccess.h>
@@ -10,7 +11,7 @@ unsigned long _copy_from_user(void *to, const void __user *from, unsigned long n
{
unsigned long res = n;
might_fault();
- if (likely(access_ok(from, n))) {
+ if (!should_fail_usercopy() && likely(access_ok(from, n))) {
instrument_copy_from_user(to, from, n);
res = raw_copy_from_user(to, from, n);
}
@@ -25,6 +26,8 @@ EXPORT_SYMBOL(_copy_from_user);
unsigned long _copy_to_user(void __user *to, const void *from, unsigned long n)
{
might_fault();
+ if (should_fail_usercopy())
+ return n;
if (likely(access_ok(to, n))) {
instrument_copy_to_user(to, from, n);
n = raw_copy_to_user(to, from, n);