This is a note to let you know that I've just added the patch titled
binder: read pre-translated fds from sender buffer
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
binder-read-pre-translated-fds-from-sender-buffer.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Wed Nov 30 01:41:25 PM CET 2022
From: Carlos Llamas <cmllamas@xxxxxxxxxx>
Date: Wed, 30 Nov 2022 03:58:01 +0000
Subject: binder: read pre-translated fds from sender buffer
To: stable@xxxxxxxxxx, "Greg Kroah-Hartman" <gregkh@xxxxxxxxxxxxxxxxxxx>, "Arve Hjønnevåg" <arve@xxxxxxxxxxx>, "Todd Kjos" <tkjos@xxxxxxxxxxx>, "Martijn Coenen" <maco@xxxxxxxxxxx>, "Joel Fernandes" <joel@xxxxxxxxxxxxxxxxx>, "Christian Brauner" <christian@xxxxxxxxxx>, "Hridya Valsaraju" <hridya@xxxxxxxxxx>, "Suren Baghdasaryan" <surenb@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx, kernel-team@xxxxxxxxxxx, Todd Kjos <tkjos@xxxxxxxxxx>, Christian Brauner <christian.brauner@xxxxxxxxxx>, Carlos Llamas <cmllamas@xxxxxxxxxx>
Message-ID: <20221130035805.1823970-3-cmllamas@xxxxxxxxxx>
From: Todd Kjos <tkjos@xxxxxxxxxx>
commit 656e01f3ab54afe71bed066996fc2640881e1220 upstream.
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>
Acked-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
Signed-off-by: Todd Kjos <tkjos@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20211130185152.437403-4-tkjos@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Carlos Llamas <cmllamas@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/android/binder.c | 39 ++++++++++++++++++++++++++++++++-------
1 file changed, 32 insertions(+), 7 deletions(-)
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2634,15 +2634,17 @@ err_fd_not_accepted:
}
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)) {
@@ -2666,7 +2668,10 @@ static int binder_translate_fd_array(str
*/
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;
@@ -2675,10 +2680,9 @@ static int binder_translate_fd_array(str
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);
@@ -3344,6 +3348,8 @@ static void binder_transaction(struct bi
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) /
@@ -3375,8 +3381,27 @@ static void binder_transaction(struct bi
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,
Patches currently in stable-queue which might be from cmllamas@xxxxxxxxxx are
queue-5.10/binder-address-corner-cases-in-deferred-copy-and-fixup.patch
queue-5.10/binder-gracefully-handle-binder_type_fda-objects-with-num_fds-0.patch
queue-5.10/binder-read-pre-translated-fds-from-sender-buffer.patch
queue-5.10/binder-avoid-potential-data-leakage-when-copying-txn.patch
queue-5.10/binder-fix-pointer-cast-warning.patch
queue-5.10/binder-defer-copies-of-pre-patched-txn-data.patch
