* [PATCH v5.15.y 1/5] binder: read pre-translated fds from sender buffer
2023-02-22 12:12 [PATCH 0/5] binder: Apply 4 missing stable fixes into v5.15.y Lee Jones
@ 2023-02-22 12:12 ` Lee Jones
2023-02-22 12:12 ` [PATCH v5.15.y 2/5] binder: defer copies of pre-patched txn data Lee Jones
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Lee Jones @ 2023-02-22 12:12 UTC (permalink / raw)
To: lee
Cc: stable, Todd Kjos, Martijn Coenen, Christian Brauner,
Greg Kroah-Hartman, Carlos Llamas
From: Todd Kjos <tkjos@google.com>
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@android.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20211130185152.437403-4-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Signed-off-by: Lee Jones <lee@kernel.org>
---
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 00c6c03ff8222..67f96d2959280 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2270,15 +2270,17 @@ 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)) {
@@ -2302,7 +2304,10 @@ 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;
@@ -2311,10 +2316,9 @@ 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);
@@ -2987,6 +2991,8 @@ 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) /
@@ -3018,8 +3024,27 @@ 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,
--
2.39.2.637.g21b0678d19-goog
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v5.15.y 2/5] binder: defer copies of pre-patched txn data
2023-02-22 12:12 [PATCH 0/5] binder: Apply 4 missing stable fixes into v5.15.y Lee Jones
2023-02-22 12:12 ` [PATCH v5.15.y 1/5] binder: read pre-translated fds from sender buffer Lee Jones
@ 2023-02-22 12:12 ` Lee Jones
2023-02-22 12:12 ` [PATCH v5.15.y 3/5] binder: fix pointer cast warning Lee Jones
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Lee Jones @ 2023-02-22 12:12 UTC (permalink / raw)
To: lee; +Cc: stable, Todd Kjos, Martijn Coenen, Greg Kroah-Hartman
From: Todd Kjos <tkjos@google.com>
commit 09184ae9b5756cc469db6fd1d1cfdcffbf627c2d upstream.
BINDER_TYPE_PTR objects point to memory areas in the
source process to be copied into the target buffer
as part of a transaction. This implements a scatter-
gather model where non-contiguous memory in a source
process is "gathered" into a contiguous region in
the target buffer.
The data can include pointers that must be fixed up
to correctly point to the copied data. To avoid making
source process pointers visible to the target process,
this patch defers the copy until the fixups are known
and then copies and fixeups are done together.
There is a special case of BINDER_TYPE_FDA which applies
the fixup later in the target process context. In this
case the user data is skipped (so no untranslated fds
become visible to the target).
Reviewed-by: Martijn Coenen <maco@android.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20211130185152.437403-5-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lee Jones <lee@kernel.org>
---
drivers/android/binder.c | 299 +++++++++++++++++++++++++++++++++++----
1 file changed, 274 insertions(+), 25 deletions(-)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 67f96d2959280..d1a9d23cdd0db 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2269,7 +2269,246 @@ static int binder_translate_fd(u32 fd, binder_size_t fd_offset,
return ret;
}
-static int binder_translate_fd_array(struct binder_fd_array_object *fda,
+/**
+ * struct binder_ptr_fixup - data to be fixed-up in target buffer
+ * @offset offset in target buffer to fixup
+ * @skip_size bytes to skip in copy (fixup will be written later)
+ * @fixup_data data to write at fixup offset
+ * @node list node
+ *
+ * This is used for the pointer fixup list (pf) which is created and consumed
+ * during binder_transaction() and is only accessed locally. No
+ * locking is necessary.
+ *
+ * The list is ordered by @offset.
+ */
+struct binder_ptr_fixup {
+ binder_size_t offset;
+ size_t skip_size;
+ binder_uintptr_t fixup_data;
+ struct list_head node;
+};
+
+/**
+ * struct binder_sg_copy - scatter-gather data to be copied
+ * @offset offset in target buffer
+ * @sender_uaddr user address in source buffer
+ * @length bytes to copy
+ * @node list node
+ *
+ * This is used for the sg copy list (sgc) which is created and consumed
+ * during binder_transaction() and is only accessed locally. No
+ * locking is necessary.
+ *
+ * The list is ordered by @offset.
+ */
+struct binder_sg_copy {
+ binder_size_t offset;
+ const void __user *sender_uaddr;
+ size_t length;
+ struct list_head node;
+};
+
+/**
+ * binder_do_deferred_txn_copies() - copy and fixup scatter-gather data
+ * @alloc: binder_alloc associated with @buffer
+ * @buffer: binder buffer in target process
+ * @sgc_head: list_head of scatter-gather copy list
+ * @pf_head: list_head of pointer fixup list
+ *
+ * Processes all elements of @sgc_head, applying fixups from @pf_head
+ * and copying the scatter-gather data from the source process' user
+ * buffer to the target's buffer. It is expected that the list creation
+ * and processing all occurs during binder_transaction() so these lists
+ * are only accessed in local context.
+ *
+ * Return: 0=success, else -errno
+ */
+static int binder_do_deferred_txn_copies(struct binder_alloc *alloc,
+ struct binder_buffer *buffer,
+ struct list_head *sgc_head,
+ struct list_head *pf_head)
+{
+ int ret = 0;
+ struct binder_sg_copy *sgc, *tmpsgc;
+ struct binder_ptr_fixup *pf =
+ list_first_entry_or_null(pf_head, struct binder_ptr_fixup,
+ node);
+
+ list_for_each_entry_safe(sgc, tmpsgc, sgc_head, node) {
+ size_t bytes_copied = 0;
+
+ while (bytes_copied < sgc->length) {
+ size_t copy_size;
+ size_t bytes_left = sgc->length - bytes_copied;
+ size_t offset = sgc->offset + bytes_copied;
+
+ /*
+ * We copy up to the fixup (pointed to by pf)
+ */
+ copy_size = pf ? min(bytes_left, (size_t)pf->offset - offset)
+ : bytes_left;
+ if (!ret && copy_size)
+ ret = binder_alloc_copy_user_to_buffer(
+ alloc, buffer,
+ offset,
+ sgc->sender_uaddr + bytes_copied,
+ copy_size);
+ bytes_copied += copy_size;
+ if (copy_size != bytes_left) {
+ BUG_ON(!pf);
+ /* we stopped at a fixup offset */
+ if (pf->skip_size) {
+ /*
+ * we are just skipping. This is for
+ * BINDER_TYPE_FDA where the translated
+ * fds will be fixed up when we get
+ * to target context.
+ */
+ bytes_copied += pf->skip_size;
+ } else {
+ /* apply the fixup indicated by pf */
+ if (!ret)
+ ret = binder_alloc_copy_to_buffer(
+ alloc, buffer,
+ pf->offset,
+ &pf->fixup_data,
+ sizeof(pf->fixup_data));
+ bytes_copied += sizeof(pf->fixup_data);
+ }
+ list_del(&pf->node);
+ kfree(pf);
+ pf = list_first_entry_or_null(pf_head,
+ struct binder_ptr_fixup, node);
+ }
+ }
+ list_del(&sgc->node);
+ kfree(sgc);
+ }
+ BUG_ON(!list_empty(pf_head));
+ BUG_ON(!list_empty(sgc_head));
+
+ return ret > 0 ? -EINVAL : ret;
+}
+
+/**
+ * binder_cleanup_deferred_txn_lists() - free specified lists
+ * @sgc_head: list_head of scatter-gather copy list
+ * @pf_head: list_head of pointer fixup list
+ *
+ * Called to clean up @sgc_head and @pf_head if there is an
+ * error.
+ */
+static void binder_cleanup_deferred_txn_lists(struct list_head *sgc_head,
+ struct list_head *pf_head)
+{
+ struct binder_sg_copy *sgc, *tmpsgc;
+ struct binder_ptr_fixup *pf, *tmppf;
+
+ list_for_each_entry_safe(sgc, tmpsgc, sgc_head, node) {
+ list_del(&sgc->node);
+ kfree(sgc);
+ }
+ list_for_each_entry_safe(pf, tmppf, pf_head, node) {
+ list_del(&pf->node);
+ kfree(pf);
+ }
+}
+
+/**
+ * binder_defer_copy() - queue a scatter-gather buffer for copy
+ * @sgc_head: list_head of scatter-gather copy list
+ * @offset: binder buffer offset in target process
+ * @sender_uaddr: user address in source process
+ * @length: bytes to copy
+ *
+ * Specify a scatter-gather block to be copied. The actual copy must
+ * be deferred until all the needed fixups are identified and queued.
+ * Then the copy and fixups are done together so un-translated values
+ * from the source are never visible in the target buffer.
+ *
+ * We are guaranteed that repeated calls to this function will have
+ * monotonically increasing @offset values so the list will naturally
+ * be ordered.
+ *
+ * Return: 0=success, else -errno
+ */
+static int binder_defer_copy(struct list_head *sgc_head, binder_size_t offset,
+ const void __user *sender_uaddr, size_t length)
+{
+ struct binder_sg_copy *bc = kzalloc(sizeof(*bc), GFP_KERNEL);
+
+ if (!bc)
+ return -ENOMEM;
+
+ bc->offset = offset;
+ bc->sender_uaddr = sender_uaddr;
+ bc->length = length;
+ INIT_LIST_HEAD(&bc->node);
+
+ /*
+ * We are guaranteed that the deferred copies are in-order
+ * so just add to the tail.
+ */
+ list_add_tail(&bc->node, sgc_head);
+
+ return 0;
+}
+
+/**
+ * binder_add_fixup() - queue a fixup to be applied to sg copy
+ * @pf_head: list_head of binder ptr fixup list
+ * @offset: binder buffer offset in target process
+ * @fixup: bytes to be copied for fixup
+ * @skip_size: bytes to skip when copying (fixup will be applied later)
+ *
+ * Add the specified fixup to a list ordered by @offset. When copying
+ * the scatter-gather buffers, the fixup will be copied instead of
+ * data from the source buffer. For BINDER_TYPE_FDA fixups, the fixup
+ * will be applied later (in target process context), so we just skip
+ * the bytes specified by @skip_size. If @skip_size is 0, we copy the
+ * value in @fixup.
+ *
+ * This function is called *mostly* in @offset order, but there are
+ * exceptions. Since out-of-order inserts are relatively uncommon,
+ * we insert the new element by searching backward from the tail of
+ * the list.
+ *
+ * Return: 0=success, else -errno
+ */
+static int binder_add_fixup(struct list_head *pf_head, binder_size_t offset,
+ binder_uintptr_t fixup, size_t skip_size)
+{
+ struct binder_ptr_fixup *pf = kzalloc(sizeof(*pf), GFP_KERNEL);
+ struct binder_ptr_fixup *tmppf;
+
+ if (!pf)
+ return -ENOMEM;
+
+ pf->offset = offset;
+ pf->fixup_data = fixup;
+ pf->skip_size = skip_size;
+ INIT_LIST_HEAD(&pf->node);
+
+ /* Fixups are *mostly* added in-order, but there are some
+ * exceptions. Look backwards through list for insertion point.
+ */
+ list_for_each_entry_reverse(tmppf, pf_head, node) {
+ if (tmppf->offset < pf->offset) {
+ list_add(&pf->node, &tmppf->node);
+ return 0;
+ }
+ }
+ /*
+ * if we get here, then the new offset is the lowest so
+ * insert at the head
+ */
+ list_add(&pf->node, pf_head);
+ return 0;
+}
+
+static int binder_translate_fd_array(struct list_head *pf_head,
+ struct binder_fd_array_object *fda,
const void __user *sender_ubuffer,
struct binder_buffer_object *parent,
struct binder_buffer_object *sender_uparent,
@@ -2281,6 +2520,7 @@ static int binder_translate_fd_array(struct binder_fd_array_object *fda,
binder_size_t fda_offset;
const void __user *sender_ufda_base;
struct binder_proc *proc = thread->proc;
+ int ret;
fd_buf_size = sizeof(u32) * fda->num_fds;
if (fda->num_fds >= SIZE_MAX / sizeof(u32)) {
@@ -2312,9 +2552,12 @@ static int binder_translate_fd_array(struct binder_fd_array_object *fda,
proc->pid, thread->pid);
return -EINVAL;
}
+ ret = binder_add_fixup(pf_head, fda_offset, 0, fda->num_fds * sizeof(u32));
+ if (ret)
+ return ret;
+
for (fdi = 0; fdi < fda->num_fds; fdi++) {
u32 fd;
- int ret;
binder_size_t offset = fda_offset + fdi * sizeof(fd);
binder_size_t sender_uoffset = fdi * sizeof(fd);
@@ -2328,7 +2571,8 @@ static int binder_translate_fd_array(struct binder_fd_array_object *fda,
return 0;
}
-static int binder_fixup_parent(struct binder_transaction *t,
+static int binder_fixup_parent(struct list_head *pf_head,
+ struct binder_transaction *t,
struct binder_thread *thread,
struct binder_buffer_object *bp,
binder_size_t off_start_offset,
@@ -2374,14 +2618,7 @@ static int binder_fixup_parent(struct binder_transaction *t,
}
buffer_offset = bp->parent_offset +
(uintptr_t)parent->buffer - (uintptr_t)b->user_data;
- if (binder_alloc_copy_to_buffer(&target_proc->alloc, b, buffer_offset,
- &bp->buffer, sizeof(bp->buffer))) {
- binder_user_error("%d:%d got transaction with invalid parent offset\n",
- proc->pid, thread->pid);
- return -EINVAL;
- }
-
- return 0;
+ return binder_add_fixup(pf_head, buffer_offset, bp->buffer, 0);
}
/**
@@ -2523,8 +2760,12 @@ static void binder_transaction(struct binder_proc *proc,
int t_debug_id = atomic_inc_return(&binder_last_id);
char *secctx = NULL;
u32 secctx_sz = 0;
+ struct list_head sgc_head;
+ struct list_head pf_head;
const void __user *user_buffer = (const void __user *)
(uintptr_t)tr->data.ptr.buffer;
+ INIT_LIST_HEAD(&sgc_head);
+ INIT_LIST_HEAD(&pf_head);
e = binder_transaction_log_add(&binder_transaction_log);
e->debug_id = t_debug_id;
@@ -3041,8 +3282,8 @@ static void binder_transaction(struct binder_proc *proc,
return_error_line = __LINE__;
goto err_bad_parent;
}
- ret = binder_translate_fd_array(fda, user_buffer,
- parent,
+ ret = binder_translate_fd_array(&pf_head, fda,
+ user_buffer, parent,
&user_object.bbo, t,
thread, in_reply_to);
if (!ret)
@@ -3074,19 +3315,14 @@ static void binder_transaction(struct binder_proc *proc,
return_error_line = __LINE__;
goto err_bad_offset;
}
- if (binder_alloc_copy_user_to_buffer(
- &target_proc->alloc,
- t->buffer,
- sg_buf_offset,
- (const void __user *)
- (uintptr_t)bp->buffer,
- bp->length)) {
- binder_user_error("%d:%d got transaction with invalid offsets ptr\n",
- proc->pid, thread->pid);
- return_error_param = -EFAULT;
+ ret = binder_defer_copy(&sgc_head, sg_buf_offset,
+ (const void __user *)(uintptr_t)bp->buffer,
+ bp->length);
+ if (ret) {
return_error = BR_FAILED_REPLY;
+ return_error_param = ret;
return_error_line = __LINE__;
- goto err_copy_data_failed;
+ goto err_translate_failed;
}
/* Fixup buffer pointer to target proc address space */
bp->buffer = (uintptr_t)
@@ -3095,7 +3331,8 @@ static void binder_transaction(struct binder_proc *proc,
num_valid = (buffer_offset - off_start_offset) /
sizeof(binder_size_t);
- ret = binder_fixup_parent(t, thread, bp,
+ ret = binder_fixup_parent(&pf_head, t,
+ thread, bp,
off_start_offset,
num_valid,
last_fixup_obj_off,
@@ -3135,6 +3372,17 @@ static void binder_transaction(struct binder_proc *proc,
return_error_line = __LINE__;
goto err_copy_data_failed;
}
+
+ ret = binder_do_deferred_txn_copies(&target_proc->alloc, t->buffer,
+ &sgc_head, &pf_head);
+ if (ret) {
+ binder_user_error("%d:%d got transaction with invalid offsets ptr\n",
+ proc->pid, thread->pid);
+ return_error = BR_FAILED_REPLY;
+ return_error_param = ret;
+ return_error_line = __LINE__;
+ goto err_copy_data_failed;
+ }
if (t->buffer->oneway_spam_suspect)
tcomplete->type = BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT;
else
@@ -3208,6 +3456,7 @@ static void binder_transaction(struct binder_proc *proc,
err_bad_offset:
err_bad_parent:
err_copy_data_failed:
+ binder_cleanup_deferred_txn_lists(&sgc_head, &pf_head);
binder_free_txn_fixups(t);
trace_binder_transaction_failed_buffer_release(t->buffer);
binder_transaction_buffer_release(target_proc, NULL, t->buffer,
--
2.39.2.637.g21b0678d19-goog
^ permalink raw reply related [flat|nested] 7+ messages in thread