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authorKees Cook <keescook@chromium.org>2017-02-13 11:25:26 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-06-12 17:25:53 +0200
commita14776fa11f1824648da3386f18e2aac31bdb1b1 (patch)
tree589cb8b0f8ea725ba32b074eb95719046de5ef39
parentf1dcd659dd83f12fd207e92351757e12e70528f4 (diff)
downloadarm64-stable-rc-a14776fa11f1824648da3386f18e2aac31bdb1b1.tar.gz
usercopy: Adjust tests to deal with SMAP/PAN
commit f5f893c57e37ca730808cb2eee3820abd05e7507 upstream. Under SMAP/PAN/etc, we cannot write directly to userspace memory, so this rearranges the test bytes to get written through copy_to_user(). Additionally drops the bad copy_from_user() test that would trigger a memcpy() against userspace on failure. [arnd: the test module was added in 3.14, and this backported patch should apply cleanly on all version from 3.14 to 4.10. The original patch was in 4.11 on top of a context change I saw the bug triggered with kselftest on a 4.4.y stable kernel] Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--lib/test_user_copy.c20
1 files changed, 18 insertions, 2 deletions
diff --git a/lib/test_user_copy.c b/lib/test_user_copy.c
index 0ecef3e..5e6db6b 100644
--- a/lib/test_user_copy.c
+++ b/lib/test_user_copy.c
@@ -58,7 +58,9 @@ static int __init test_user_copy_init(void)
usermem = (char __user *)user_addr;
bad_usermem = (char *)user_addr;
- /* Legitimate usage: none of these should fail. */
+ /*
+ * Legitimate usage: none of these copies should fail.
+ */
ret |= test(copy_from_user(kmem, usermem, PAGE_SIZE),
"legitimate copy_from_user failed");
ret |= test(copy_to_user(usermem, kmem, PAGE_SIZE),
@@ -68,19 +70,33 @@ static int __init test_user_copy_init(void)
ret |= test(put_user(value, (unsigned long __user *)usermem),
"legitimate put_user failed");
- /* Invalid usage: none of these should succeed. */
+ /*
+ * Invalid usage: none of these copies should succeed.
+ */
+
+ /* Reject kernel-to-kernel copies through copy_from_user(). */
ret |= test(!copy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE),
PAGE_SIZE),
"illegal all-kernel copy_from_user passed");
+
+#if 0
+ /*
+ * When running with SMAP/PAN/etc, this will Oops the kernel
+ * due to the zeroing of userspace memory on failure. This needs
+ * to be tested in LKDTM instead, since this test module does not
+ * expect to explode.
+ */
ret |= test(!copy_from_user(bad_usermem, (char __user *)kmem,
PAGE_SIZE),
"illegal reversed copy_from_user passed");
+#endif
ret |= test(!copy_to_user((char __user *)kmem, kmem + PAGE_SIZE,
PAGE_SIZE),
"illegal all-kernel copy_to_user passed");
ret |= test(!copy_to_user((char __user *)kmem, bad_usermem,
PAGE_SIZE),
"illegal reversed copy_to_user passed");
+
ret |= test(!get_user(value, (unsigned long __user *)kmem),
"illegal get_user passed");
ret |= test(!put_user(value, (unsigned long __user *)kmem),