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authorArnd Bergmann <arnd@arndb.de>2022-02-16 13:48:06 +0100
committerArnd Bergmann <arnd@arndb.de>2022-02-25 09:36:06 +0100
commit5a06fcb15b43d1f7bf740c672950122331cb5655 (patch)
tree115409abe923229be6f68fc285a7063988fc295a /lib/test_lockup.c
parent12700c17fc286149324f92d6d380bc48e43f253d (diff)
lib/test_lockup: fix kernel pointer check for separate address spaces
test_kernel_ptr() uses access_ok() to figure out if a given address points to user space instead of kernel space. However on architectures that set CONFIG_ALTERNATE_USER_ADDRESS_SPACE, a pointer can be valid for both, and the check always fails because access_ok() returns true. Make the check for user space pointers conditional on the type of address space layout. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'lib/test_lockup.c')
-rw-r--r--lib/test_lockup.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/lib/test_lockup.c b/lib/test_lockup.c
index 6a0f329a794a..c3fd87d6c2dd 100644
--- a/lib/test_lockup.c
+++ b/lib/test_lockup.c
@@ -417,9 +417,14 @@ static bool test_kernel_ptr(unsigned long addr, int size)
return false;
/* should be at least readable kernel address */
- if (access_ok((void __user *)ptr, 1) ||
- access_ok((void __user *)ptr + size - 1, 1) ||
- get_kernel_nofault(buf, ptr) ||
+ if (!IS_ENABLED(CONFIG_ALTERNATE_USER_ADDRESS_SPACE) &&
+ (access_ok((void __user *)ptr, 1) ||
+ access_ok((void __user *)ptr + size - 1, 1))) {
+ pr_err("user space ptr invalid in kernel: %#lx\n", addr);
+ return true;
+ }
+
+ if (get_kernel_nofault(buf, ptr) ||
get_kernel_nofault(buf, ptr + size - 1)) {
pr_err("invalid kernel ptr: %#lx\n", addr);
return true;