This patch is to prepare for an up coming patch where we read
pre-translated fds from the sender buffer and translate them before
copying them to the target. It does not change run time.
The patch adds two new parameters to binder_translate_fd_array() to
hold the sender buffer and sender buffer parent. These parameters let
us call copy_from_user() directly from the sender instead of using
binder_alloc_copy_from_buffer() to copy from the target. Also the patch
adds some new alignment checks. Previously the alignment checks would
have been done in a different place, but this lets us print more
useful error messages.
Reviewed-by: Martijn Coenen <maco@xxxxxxxxxxx>
Signed-off-by: Todd Kjos <tkjos@xxxxxxxxxx>
---
v2: Addressed comments from Dan Carpenter
- Re-wrote commit message as suggested
- renamed "u" and "user" locals to "sender_*" for clarity
- fixed printk format for size_t
drivers/android/binder.c | 39 ++++++++++++++++++++++++++++++++-------
1 file changed, 32 insertions(+), 7 deletions(-)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 3cd3e82866aa..9eb24d8a4d2f 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2234,15 +2234,17 @@ static int binder_translate_fd(u32 fd, binder_size_t fd_offset,
}
static int binder_translate_fd_array(struct binder_fd_array_object *fda,
+ const void __user *sender_ubuffer,
struct binder_buffer_object *parent,
+ struct binder_buffer_object *sender_uparent,
struct binder_transaction *t,
struct binder_thread *thread,
struct binder_transaction *in_reply_to)
{
binder_size_t fdi, fd_buf_size;
binder_size_t fda_offset;
+ const void __user *sender_ufda_base;
struct binder_proc *proc = thread->proc;
- struct binder_proc *target_proc = t->to_proc;
fd_buf_size = sizeof(u32) * fda->num_fds;
if (fda->num_fds >= SIZE_MAX / sizeof(u32)) {
@@ -2266,7 +2268,10 @@ static int binder_translate_fd_array(struct binder_fd_array_object *fda,
*/
fda_offset = (parent->buffer - (uintptr_t)t->buffer->user_data) +
fda->parent_offset;
- if (!IS_ALIGNED((unsigned long)fda_offset, sizeof(u32))) {
+ sender_ufda_base = (void __user *)sender_uparent->buffer + fda->parent_offset;
+
+ if (!IS_ALIGNED((unsigned long)fda_offset, sizeof(u32)) ||
+ !IS_ALIGNED((unsigned long)sender_ufda_base, sizeof(u32))) {
binder_user_error("%d:%d parent offset not aligned correctly.\n",
proc->pid, thread->pid);
return -EINVAL;
@@ -2275,10 +2280,9 @@ static int binder_translate_fd_array(struct binder_fd_array_object *fda,
u32 fd;
int ret;
binder_size_t offset = fda_offset + fdi * sizeof(fd);
+ binder_size_t sender_uoffset = fdi * sizeof(fd);
- ret = binder_alloc_copy_from_buffer(&target_proc->alloc,
- &fd, t->buffer,
- offset, sizeof(fd));
+ ret = copy_from_user(&fd, sender_ufda_base + sender_uoffset, sizeof(fd));
if (!ret)
ret = binder_translate_fd(fd, offset, t, thread,
in_reply_to);
@@ -2951,6 +2955,8 @@ static void binder_transaction(struct binder_proc *proc,
case BINDER_TYPE_FDA: {
struct binder_object ptr_object;
binder_size_t parent_offset;
+ struct binder_object user_object;
+ size_t user_parent_size;
struct binder_fd_array_object *fda =
to_binder_fd_array_object(hdr);
size_t num_valid = (buffer_offset - off_start_offset) /
@@ -2982,8 +2988,27 @@ static void binder_transaction(struct binder_proc *proc,
return_error_line = __LINE__;
goto err_bad_parent;
}
- ret = binder_translate_fd_array(fda, parent, t, thread,
- in_reply_to);
+ /*
+ * We need to read the user version of the parent
+ * object to get the original user offset
+ */
+ user_parent_size =
+ binder_get_object(proc, user_buffer, t->buffer,
+ parent_offset, &user_object);
+ if (user_parent_size != sizeof(user_object.bbo)) {
+ binder_user_error("%d:%d invalid ptr object size: %zd vs %zd\n",
+ proc->pid, thread->pid,
+ user_parent_size,
+ sizeof(user_object.bbo));
+ return_error = BR_FAILED_REPLY;
+ return_error_param = -EINVAL;
+ return_error_line = __LINE__;
+ goto err_bad_parent;
+ }
+ ret = binder_translate_fd_array(fda, user_buffer,
+ parent,
+ &user_object.bbo, t,
+ thread, in_reply_to);
if (!ret)
ret = binder_alloc_copy_to_buffer(&target_proc->alloc,
t->buffer,
--
2.34.0.rc2.393.gf8c9666880-goog
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