[RESEND PATCH v3 2/2] binder: Validate the default binderfs device names.

From: Christian Brauner
Date: Wed Sep 04 2019 - 07:07:18 EST


From: Hridya Valsaraju <hridya@xxxxxxxxxx>

Length of a binderfs device name cannot exceed BINDERFS_MAX_NAME.
This patch adds a check in binderfs_init() to ensure the same
for the default binder devices that will be created in every
binderfs instance.

Co-developed-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
Signed-off-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
Signed-off-by: Hridya Valsaraju <hridya@xxxxxxxxxx>
Reviewed-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20190808222727.132744-3-hridya@xxxxxxxxxx
---
drivers/android/binderfs.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
index aee46dd1be91..55c5adb87585 100644
--- a/drivers/android/binderfs.c
+++ b/drivers/android/binderfs.c
@@ -570,6 +570,18 @@ static struct file_system_type binder_fs_type = {
int __init init_binderfs(void)
{
int ret;
+ const char *name;
+ size_t len;
+
+ /* Verify that the default binderfs device names are valid. */
+ name = binder_devices_param;
+ for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
+ if (len > BINDERFS_MAX_NAME)
+ return -E2BIG;
+ name += len;
+ if (*name == ',')
+ name++;
+ }

/* Allocate new major number for binderfs. */
ret = alloc_chrdev_region(&binderfs_dev, 0, BINDERFS_MAX_MINOR,
--
2.23.0