commit 573ae4f13f630d6660008f1974c0a8a29c30e18a upstream.
With special lengths supplied by user space, tee_shm_register() has
an integer overflow when calculating the number of pages covered by a
supplied user space memory region.
This may cause pin_user_pages_fast() to do a NULL pointer dereference.
Fix this by adding an an explicit call to access_ok() in
tee_ioctl_shm_register() to catch an invalid user space address early.
Fixes: 033ddf12bcf5 ("tee: add register user memory")
Cc: stable@xxxxxxxxxxxxxxx # 4.19
Reported-by: Nimish Mishra <neelam.nimish@xxxxxxxxx>
Reported-by: Anirban Chakraborty <ch.anirban00727@xxxxxxxxx>
Reported-by: Debdeep Mukhopadhyay <debdeep.mukhopadhyay@xxxxxxxxx>
Suggested-by: Jerome Forissier <jerome.forissier@xxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
[JW: backport to stable-4.19 + update commit message]
Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
---
drivers/tee/tee_core.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
index d42fc2ae8592..e568cb4b2ffc 100644
--- a/drivers/tee/tee_core.c
+++ b/drivers/tee/tee_core.c
@@ -175,6 +175,10 @@ tee_ioctl_shm_register(struct tee_context *ctx,
if (data.flags)
return -EINVAL;
+ if (!access_ok(VERIFY_WRITE, (void __user *)(unsigned long)data.addr,
+ data.length))
+ return -EFAULT;
+
shm = tee_shm_register(ctx, data.addr, data.length,
TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED);
if (IS_ERR(shm))
--
2.31.1
