user/sven/linux.git/drivers/android, branch v5.8.8

binder: Prevent context manager from incrementing ref 0

2020-08-11T13:48:09Z

commit 4b836a1426cb0f1ef2a6e211d7e553221594f8fc upstream. 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

treewide: replace '---help---' in Kconfig files with 'help'

2020-06-13T16:57:21Z

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over '---help---'"), the number of '---help---' has been gradually decreasing, but there are still more than 2400 instances. This commit finishes the conversion. While I touched the lines, I also fixed the indentation. There are a variety of indentation styles found. a) 4 spaces + '---help---' b) 7 spaces + '---help---' c) 8 spaces + '---help---' d) 1 space + 1 tab + '---help---' e) 1 tab + '---help---' (correct indentation) f) 1 tab + 1 space + '---help---' g) 1 tab + 2 spaces + '---help---' In order to convert all of them to 1 tab + 'help', I ran the following commend: $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/' Signed-off-by: Masahiro Yamada

mmap locking API: convert mmap_sem API comments

2020-06-09T16:39:14Z

Convert comments that reference old mmap_sem APIs to reference corresponding new mmap locking APIs instead. Signed-off-by: Michel Lespinasse Signed-off-by: Andrew Morton Reviewed-by: Vlastimil Babka Reviewed-by: Davidlohr Bueso Reviewed-by: Daniel Jordan Cc: David Rientjes Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Laurent Dufour Cc: Liam Howlett Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Ying Han Link: http://lkml.kernel.org/r/20200520052908.204642-12-walken@google.com Signed-off-by: Linus Torvalds

mmap locking API: use coccinelle to convert mmap_sem rwsem call sites

2020-06-09T16:39:14Z

This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse Signed-off-by: Andrew Morton Reviewed-by: Daniel Jordan Reviewed-by: Laurent Dufour Reviewed-by: Vlastimil Babka Cc: Davidlohr Bueso Cc: David Rientjes Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Liam Howlett Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Ying Han Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds

binderfs: remove redundant assignment to pointer ctx

2020-04-23T14:48:11Z

The pointer ctx is being initialized with a value that is never read and it is being updated later with a new value. The initialization is redundant and can be removed. Addresses-Coverity: ("Unused value") Signed-off-by: Colin Ian King Acked-by: Christian Brauner Link: https://lore.kernel.org/r/20200402105000.506296-1-colin.king@canonical.com Signed-off-by: Greg Kroah-Hartman

binderfs: Fix binderfs.c selftest compilation warning

2020-04-23T14:48:00Z

Fix missing braces compilation warning in the ARM compiler environment: drivers/android/binderfs.c: In function 'binderfs_fill_super': drivers/android/binderfs.c:650:9: warning: missing braces around initializer [-Wmissing-braces] struct binderfs_device device_info = { 0 }; drivers/android/binderfs.c:650:9: warning: (near initialization for ‘device_info.name’) [-Wmissing-braces] Acked-by: Christian Brauner Signed-off-by: Tang Bin Link: https://lore.kernel.org/r/20200411145151.5576-1-tangbin@cmss.chinamobile.com Signed-off-by: Greg Kroah-Hartman

Merge 5.6-rc7 into char-misc-next

2020-03-23T06:59:38Z

We need the char/misc driver fixes in here as well. Signed-off-by: Greg Kroah-Hartman

binderfs: port to new mount api

2020-03-19T06:41:01Z

When I first wrote binderfs the new mount api had not yet landed. Now that it has been around for a little while and a bunch of filesystems have already been ported we should do so too. When Al sent his mount-api-conversion pr he requested that binderfs (and a few others) be ported separately. It's time we port binderfs. We can make use of the new option parser, get nicer infrastructure and it will be easier if we ever add any new mount options. This survives testing with the binderfs selftests: for i in `seq 1 1000`; do ./binderfs_test; done including the new stress tests I sent out for review today: TAP version 13 1..1 # selftests: filesystems/binderfs: binderfs_test # [==========] Running 3 tests from 1 test cases. # [ RUN ] global.binderfs_stress # [ XFAIL! ] Tests are not run as root. Skipping privileged tests # [==========] Running 3 tests from 1 test cases. # [ RUN ] global.binderfs_stress # [ OK ] global.binderfs_stress # [ RUN ] global.binderfs_test_privileged # [ OK ] global.binderfs_test_privileged # [ RUN ] global.binderfs_test_unprivileged # # Allocated new binder device with major 243, minor 4, and name my-binder # # Detected binder version: 8 # [==========] Running 3 tests from 1 test cases. # [ RUN ] global.binderfs_stress # [ OK ] global.binderfs_stress # [ RUN ] global.binderfs_test_privileged # [ OK ] global.binderfs_test_privileged # [ RUN ] global.binderfs_test_unprivileged # [ OK ] global.binderfs_test_unprivileged # [==========] 3 / 3 tests passed. # [ PASSED ] ok 1 selftests: filesystems/binderfs: binderfs_test Cc: Todd Kjos Signed-off-by: Christian Brauner Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20200313153427.141789-1-christian.brauner@ubuntu.com Signed-off-by: Greg Kroah-Hartman