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| author | Jann Horn <jannh@google.com> | 2018-08-28 22:14:21 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-09-03 15:12:10 +0200 |
| commit | bef459026b161fbc39d20dcba698ed0cfffbac38 (patch) | |
| tree | da222ce16f935127b188f773d843a95f1f9dca4a /drivers/misc/lkdtm/usercopy.c | |
| parent | 9da3f2b74054406f87dff7101a569217ffceb29b (diff) | |
| download | linux-bef459026b161fbc39d20dcba698ed0cfffbac38.tar.bz2 | |
lkdtm: Test copy_to_user() on bad kernel pointer under KERNEL_DS
Test whether the kernel WARN()s when, under KERNEL_DS, a bad kernel pointer
is used as "userspace" pointer. Should normally be used in "DIRECT" mode.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Kees Cook <keescook@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: kernel-hardening@lists.openwall.com
Cc: dvyukov@google.com
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20180828201421.157735-8-jannh@google.com
Diffstat (limited to 'drivers/misc/lkdtm/usercopy.c')
| -rw-r--r-- | drivers/misc/lkdtm/usercopy.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c index 9725aed305bb..389475b25bb7 100644 --- a/drivers/misc/lkdtm/usercopy.c +++ b/drivers/misc/lkdtm/usercopy.c @@ -322,6 +322,19 @@ free_user: vm_munmap(user_addr, PAGE_SIZE); } +void lkdtm_USERCOPY_KERNEL_DS(void) +{ + char __user *user_ptr = (char __user *)ERR_PTR(-EINVAL); + mm_segment_t old_fs = get_fs(); + char buf[10] = {0}; + + pr_info("attempting copy_to_user on unmapped kernel address\n"); + set_fs(KERNEL_DS); + if (copy_to_user(user_ptr, buf, sizeof(buf))) + pr_info("copy_to_user un unmapped kernel address failed\n"); + set_fs(old_fs); +} + void __init lkdtm_usercopy_init(void) { /* Prepare cache that lacks SLAB_USERCOPY flag. */ |