user/sven/linux.git/drivers/android, branch v5.9.8

binder: Remove bogus warning on failed same-process transaction

2020-10-29T09:11:16Z

[ Upstream commit e8b8ae7ce32e17a5c29f0289e9e2a39c7dcaa1b8 ] While binder transactions with the same binder_proc as sender and recipient are forbidden, transactions with the same task_struct as sender and recipient are possible (even though currently there is a weird check in binder_transaction() that rejects them in the target==0 case). Therefore, task_struct identities can't be used to distinguish whether the caller is running in the context of the sender or the recipient. Since I see no easy way to make this WARN_ON() useful and correct, let's just remove it. Fixes: 44d8047f1d87 ("binder: use standard functions to allocate fds") Reported-by: syzbot+e113a0b970b7b3f394ba@syzkaller.appspotmail.com Acked-by: Christian Brauner Acked-by: Todd Kjos Signed-off-by: Jann Horn Link: https://lore.kernel.org/r/20200806165359.2381483-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

binder: fix UAF when releasing todo list

2020-10-29T09:10:52Z

commit f3277cbfba763cd2826396521b9296de67cf1bbc upstream. When releasing a thread todo list when tearing down a binder_proc, the following race was possible which could result in a use-after-free: 1. Thread 1: enter binder_release_work from binder_thread_release 2. Thread 2: binder_update_ref_for_handle() -> binder_dec_node_ilocked() 3. Thread 2: dec nodeA --> 0 (will free node) 4. Thread 1: ACQ inner_proc_lock 5. Thread 2: block on inner_proc_lock 6. Thread 1: dequeue work (BINDER_WORK_NODE, part of nodeA) 7. Thread 1: REL inner_proc_lock 8. Thread 2: ACQ inner_proc_lock 9. Thread 2: todo list cleanup, but work was already dequeued 10. Thread 2: free node 11. Thread 2: REL inner_proc_lock 12. Thread 1: deref w->type (UAF) The problem was that for a BINDER_WORK_NODE, the binder_work element must not be accessed after releasing the inner_proc_lock while processing the todo list elements since another thread might be handling a deref on the node containing the binder_work element leading to the node being freed. Signed-off-by: Todd Kjos Link: https://lore.kernel.org/r/20201009232455.4054810-1-tkjos@google.com Cc: # 4.14, 4.19, 5.4, 5.8 Signed-off-by: Greg Kroah-Hartman

drivers: android: Fix the SPDX comment style

2020-07-29T15:05:44Z

C source files should have `//` as SPDX comment and not `/**/`. Fix this by running checkpatch on the file. Signed-off-by: Mrinal Pandey Link: https://lore.kernel.org/r/20200724131449.zvjutbemg3vqhrzh@mrinalpandey Signed-off-by: Greg Kroah-Hartman

drivers: android: Fix a variable declaration coding style issue

2020-07-29T15:05:44Z

Add a blank line after variable declarations as suggested by checkpatch. Signed-off-by: Mrinal Pandey Link: https://lore.kernel.org/r/20200724131433.stf3ycooogawyzb3@mrinalpandey Signed-off-by: Greg Kroah-Hartman

drivers: android: Remove braces for a single statement if-else block

2020-07-29T15:05:38Z

Remove braces for both if and else block as suggested by checkpatch. Signed-off-by: Mrinal Pandey Link: https://lore.kernel.org/r/20200724131403.dahfhdwa3wirzkxj@mrinalpandey Signed-off-by: Greg Kroah-Hartman

drivers: android: Remove the use of else after return

2020-07-29T15:05:38Z

Remove the unnecessary else branch after return statement as suggested by checkpatch. Signed-off-by: Mrinal Pandey Link: https://lore.kernel.org/r/20200724131348.haz4ocxcferdcsgn@mrinalpandey Signed-off-by: Greg Kroah-Hartman

drivers: android: Fix a variable declaration coding style issue

2020-07-29T15:04:40Z

Add a blank line after variable declarations as suggested by checkpatch. Signed-off-by: Mrinal Pandey Link: https://lore.kernel.org/r/20200724131254.qxbvderrws36dzzq@mrinalpandey Signed-off-by: Greg Kroah-Hartman

binder: Prevent context manager from incrementing ref 0

2020-07-29T15:04:40Z

Binder is designed such that a binder_proc never has references to itself. If this rule is violated, memory corruption can occur when a process sends a transaction to itself; see e.g. . There is a remaining edgecase through which such a transaction-to-self can still occur from the context of a task with BINDER_SET_CONTEXT_MGR access: - task A opens /dev/binder twice, creating binder_proc instances P1 and P2 - P1 becomes context manager - P2 calls ACQUIRE on the magic handle 0, allocating index 0 in its handle table - P1 dies (by closing the /dev/binder fd and waiting a bit) - P2 becomes context manager - P2 calls ACQUIRE on the magic handle 0, allocating index 1 in its handle table [this triggers a warning: "binder: 1974:1974 tried to acquire reference to desc 0, got 1 instead"] - task B opens /dev/binder once, creating binder_proc instance P3 - P3 calls P2 (via magic handle 0) with (void*)1 as argument (two-way transaction) - P2 receives the handle and uses it to call P3 (two-way transaction) - P3 calls P2 (via magic handle 0) (two-way transaction) - P2 calls P2 (via handle 1) (two-way transaction) And then, if P2 does *NOT* accept the incoming transaction work, but instead closes the binder fd, we get a crash. Solve it by preventing the context manager from using ACQUIRE on ref 0. There shouldn't be any legitimate reason for the context manager to do that. Additionally, print a warning if someone manages to find another way to trigger a transaction-to-self bug in the future. Cc: stable@vger.kernel.org Fixes: 457b9a6f09f0 ("Staging: android: add binder driver") Acked-by: Todd Kjos Signed-off-by: Jann Horn Reviewed-by: Martijn Coenen Link: https://lore.kernel.org/r/20200727120424.1627555-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman

binder: Don't use mmput() from shrinker function.

2020-07-23T07:47:12Z

syzbot is reporting that mmput() from shrinker function has a risk of deadlock [1], for delayed_uprobe_add() from update_ref_ctr() calls kzalloc(GFP_KERNEL) with delayed_uprobe_lock held, and uprobe_clear_state() from __mmput() also holds delayed_uprobe_lock. Commit a1b2289cef92ef0e ("android: binder: drop lru lock in isolate callback") replaced mmput() with mmput_async() in order to avoid sleeping with spinlock held. But this patch replaces mmput() with mmput_async() in order not to start __mmput() from shrinker context. [1] https://syzkaller.appspot.com/bug?id=bc9e7303f537c41b2b0cc2dfcea3fc42964c2d45 Reported-by: syzbot Reported-by: syzbot Signed-off-by: Tetsuo Handa Reviewed-by: Michal Hocko Acked-by: Todd Kjos Acked-by: Christian Brauner Cc: stable Link: https://lore.kernel.org/r/4ba9adb2-43f5-2de0-22de-f6075c1fab50@i-love.sakura.ne.jp Signed-off-by: Greg Kroah-Hartman

binder: fix null deref of proc->context

2020-06-23T05:54:46Z

The binder driver makes the assumption proc->context pointer is invariant after initialization (as documented in the kerneldoc header for struct proc). However, in commit f0fe2c0f050d ("binder: prevent UAF for binderfs devices II") proc->context is set to NULL during binder_deferred_release(). Another proc was in the middle of setting up a transaction to the dying process and crashed on a NULL pointer deref on "context" which is a local set to &proc->context: new_ref->data.desc = (node == context->binder_context_mgr_node) ? 0 : 1; Here's the stack: [ 5237.855435] Call trace: [ 5237.855441] binder_get_ref_for_node_olocked+0x100/0x2ec [ 5237.855446] binder_inc_ref_for_node+0x140/0x280 [ 5237.855451] binder_translate_binder+0x1d0/0x388 [ 5237.855456] binder_transaction+0x2228/0x3730 [ 5237.855461] binder_thread_write+0x640/0x25bc [ 5237.855466] binder_ioctl_write_read+0xb0/0x464 [ 5237.855471] binder_ioctl+0x30c/0x96c [ 5237.855477] do_vfs_ioctl+0x3e0/0x700 [ 5237.855482] __arm64_sys_ioctl+0x78/0xa4 [ 5237.855488] el0_svc_common+0xb4/0x194 [ 5237.855493] el0_svc_handler+0x74/0x98 [ 5237.855497] el0_svc+0x8/0xc The fix is to move the kfree of the binder_device to binder_free_proc() so the binder_device is freed when we know there are no references remaining on the binder_proc. Fixes: f0fe2c0f050d ("binder: prevent UAF for binderfs devices II") Acked-by: Christian Brauner Signed-off-by: Todd Kjos Cc: stable Link: https://lore.kernel.org/r/20200622200715.114382-1-tkjos@google.com Signed-off-by: Greg Kroah-Hartman