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* fs: make helpers idmap mount awareChristian Brauner2021-01-241-2/+4
| | | | | | | | | | | | | | | | | | | | | Extend some inode methods with an additional user namespace argument. A filesystem that is aware of idmapped mounts will receive the user namespace the mount has been marked with. This can be used for additional permission checking and also to enable filesystems to translate between uids and gids if they need to. We have implemented all relevant helpers in earlier patches. As requested we simply extend the exisiting inode method instead of introducing new ones. This is a little more code churn but it's mostly mechanical and doesnt't leave us with additional inode methods. Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
* Merge branch 'exec-for-v5.11' of ↵Linus Torvalds2020-12-151-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull execve updates from Eric Biederman: "This set of changes ultimately fixes the interaction of posix file lock and exec. Fundamentally most of the change is just moving where unshare_files is called during exec, and tweaking the users of files_struct so that the count of files_struct is not unnecessarily played with. Along the way fcheck and related helpers were renamed to more accurately reflect what they do. There were also many other small changes that fell out, as this is the first time in a long time much of this code has been touched. Benchmarks haven't turned up any practical issues but Al Viro has observed a possibility for a lot of pounding on task_lock. So I have some changes in progress to convert put_files_struct to always rcu free files_struct. That wasn't ready for the merge window so that will have to wait until next time" * 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits) exec: Move io_uring_task_cancel after the point of no return coredump: Document coredump code exclusively used by cell spufs file: Remove get_files_struct file: Rename __close_fd_get_file close_fd_get_file file: Replace ksys_close with close_fd file: Rename __close_fd to close_fd and remove the files parameter file: Merge __alloc_fd into alloc_fd file: In f_dupfd read RLIMIT_NOFILE once. file: Merge __fd_install into fd_install proc/fd: In fdinfo seq_show don't use get_files_struct bpf/task_iter: In task_file_seq_get_next use task_lookup_next_fd_rcu proc/fd: In proc_readfd_common use task_lookup_next_fd_rcu file: Implement task_lookup_next_fd_rcu kcmp: In get_file_raw_ptr use task_lookup_fd_rcu proc/fd: In tid_fd_mode use task_lookup_fd_rcu file: Implement task_lookup_fd_rcu file: Rename fcheck lookup_fd_rcu file: Replace fcheck_files with files_lookup_fd_rcu file: Factor files_lookup_fd_locked out of fcheck_files file: Rename __fcheck_files to files_lookup_fd_raw ...
| * file: Rename __close_fd_get_file close_fd_get_fileEric W. Biederman2020-12-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The function close_fd_get_file is explicitly a variant of __close_fd[1]. Now that __close_fd has been renamed close_fd, rename close_fd_get_file to be consistent with close_fd. When __alloc_fd, __close_fd and __fd_install were introduced the double underscore indicated that the function took a struct files_struct parameter. The function __close_fd_get_file never has so the naming has always been inconsistent. This just cleans things up so there are not any lingering mentions or references __close_fd left in the code. [1] 80cd795630d6 ("binder: fix use-after-free due to ksys_close() during fdget()") Link: https://lkml.kernel.org/r/20201120231441.29911-23-ebiederm@xmission.com Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* | binder: add flag to clear buffer on txn completeTodd Kjos2020-12-093-1/+52
| | | | | | | | | | | | | | | | | | | | | | | | Add a per-transaction flag to indicate that the buffer must be cleared when the transaction is complete to prevent copies of sensitive data from being preserved in memory. Signed-off-by: Todd Kjos <tkjos@google.com> Link: https://lore.kernel.org/r/20201120233743.3617529-1-tkjos@google.com Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | binder: add trace at free transaction.Frankie.Chang2020-11-112-0/+47
| | | | | | | | | | | | | | | | | | | | | | | | Since the original trace_binder_transaction_received cannot precisely present the real finished time of transaction, adding a trace_binder_txn_latency_free at the point of free transaction may be more close to it. Signed-off-by: Frankie.Chang <Frankie.Chang@mediatek.com> Acked-by: Todd Kjos <tkjos@google.com> Link: https://lore.kernel.org/r/1605063764-12930-3-git-send-email-Frankie.Chang@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | binder: move structs from core file to header fileFrankie.Chang2020-11-112-406/+406
| | | | | | | | | | | | | | | | | | | | | | Moving all structs to header file makes module more extendable, and makes all these structs to be defined in the same file. Signed-off-by: Frankie.Chang <Frankie.Chang@mediatek.com> Acked-by: Todd Kjos <tkjos@google.com> Link: https://lore.kernel.org/r/1605063764-12930-2-git-send-email-Frankie.Chang@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | binder: change error code from postive to negative in binder_transactionZhang Qilong2020-11-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Depending on the context, the error return value here (extra_buffers_size < added_size) should be negative. Acked-by: Martijn Coenen <maco@android.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com> Link: https://lore.kernel.org/r/20201026110314.135481-1-zhangqilong3@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | Android: binder: added a missing blank line after declarationAndrew Bridges2020-11-091-0/+1
|/ | | | | | | | Fixed a coding style issue. Signed-off-by: Andrew Bridges <andrew@slova.app> Link: https://lore.kernel.org/r/20201027225655.650922-1-andrew@slova.app Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* task_work: cleanup notification modesJens Axboe2020-10-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | A previous commit changed the notification mode from true/false to an int, allowing notify-no, notify-yes, or signal-notify. This was backwards compatible in the sense that any existing true/false user would translate to either 0 (on notification sent) or 1, the latter which mapped to TWA_RESUME. TWA_SIGNAL was assigned a value of 2. Clean this up properly, and define a proper enum for the notification mode. Now we have: - TWA_NONE. This is 0, same as before the original change, meaning no notification requested. - TWA_RESUME. This is 1, same as before the original change, meaning that we use TIF_NOTIFY_RESUME. - TWA_SIGNAL. This uses TIF_SIGPENDING/JOBCTL_TASK_WORK for the notification. Clean up all the callers, switching their 0/1/false/true to using the appropriate TWA_* mode for notifications. Fixes: e91b48162332 ("task_work: teach task_work_add() to do signal_wake_up()") Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* binder: fix UAF when releasing todo listTodd Kjos2020-10-101-25/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <tkjos@google.com> Link: https://lore.kernel.org/r/20201009232455.4054810-1-tkjos@google.com Cc: <stable@vger.kernel.org> # 4.14, 4.19, 5.4, 5.8 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* binder: simplify the return expression of binder_mmapLiu Shixin2020-10-051-14/+4
| | | | | | | | | | Simplify the return expression. Acked-by: Martijn Coenen <maco@android.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Liu Shixin <liushixin2@huawei.com> Link: https://lore.kernel.org/r/20200929015216.1829946-1-liushixin2@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* binder: remove redundant assignment to pointer nColin Ian King2020-09-161-1/+1
| | | | | | | | | | | | The pointer n 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. Acked-by: Todd Kjos <tkjos@google.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Colin Ian King <colin.king@canonical.com> Link: https://lore.kernel.org/r/20200910151221.751464-1-colin.king@canonical.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* binder: print warnings when detecting oneway spamming.Martijn Coenen2020-09-034-6/+58
| | | | | | | | | | | | | | | | | | The most common cause of the binder transaction buffer filling up is a client rapidly firing oneway transactions into a process, before it has a chance to handle them. Yet the root cause of this is often hard to debug, because either the system or the app will stop, and by that time binder debug information we dump in bugreports is no longer relevant. This change warns as soon as a process dips below 80% of its oneway space (less than 100kB available in the configuration), when any one process is responsible for either more than 50 transactions, or more than 50% of the oneway space. Signed-off-by: Martijn Coenen <maco@android.com> Acked-by: Todd Kjos <tkjos@google.com> Link: https://lore.kernel.org/r/20200821122544.1277051-1-maco@android.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* binderfs: make symbol 'binderfs_fs_parameters' staticWei Yongjun2020-09-031-1/+1
| | | | | | | | | | | | | | | | | The sparse tool complains as follows: drivers/android/binderfs.c:66:32: warning: symbol 'binderfs_fs_parameters' was not declared. Should it be static? This variable is not used outside of binderfs.c, so this commit marks it static. Fixes: 095cf502b31e ("binderfs: port to new mount api") Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/r/20200818112245.43891-1-weiyongjun1@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* binder: Modify commentsYangHui2020-09-031-1/+1
| | | | | | | | | The function name should is binder_alloc_new_buf() Signed-off-by: YangHui <yanghui.def@gmail.com> Reviewed-by: Martijn Coenen <maco@android.com> Link: https://lore.kernel.org/r/1597714444-3614-1-git-send-email-yanghui.def@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* binder: Remove bogus warning on failed same-process transactionJann Horn2020-09-031-2/+0
| | | | | | | | | | | | | | | | | | | | 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 <christian.brauner@ubuntu.com> Acked-by: Todd Kjos <tkjos@google.com> Signed-off-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20200806165359.2381483-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* drivers: android: Fix the SPDX comment styleMrinal Pandey2020-07-291-1/+1
| | | | | | | | | C source files should have `//` as SPDX comment and not `/**/`. Fix this by running checkpatch on the file. Signed-off-by: Mrinal Pandey <mrinalmni@gmail.com> Link: https://lore.kernel.org/r/20200724131449.zvjutbemg3vqhrzh@mrinalpandey Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* drivers: android: Fix a variable declaration coding style issueMrinal Pandey2020-07-291-0/+1
| | | | | | | | Add a blank line after variable declarations as suggested by checkpatch. Signed-off-by: Mrinal Pandey <mrinalmni@gmail.com> Link: https://lore.kernel.org/r/20200724131433.stf3ycooogawyzb3@mrinalpandey Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* drivers: android: Remove braces for a single statement if-else blockMrinal Pandey2020-07-291-3/+2
| | | | | | | | Remove braces for both if and else block as suggested by checkpatch. Signed-off-by: Mrinal Pandey <mrinalmni@gmail.com> Link: https://lore.kernel.org/r/20200724131403.dahfhdwa3wirzkxj@mrinalpandey Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* drivers: android: Remove the use of else after returnMrinal Pandey2020-07-291-2/+1
| | | | | | | | | Remove the unnecessary else branch after return statement as suggested by checkpatch. Signed-off-by: Mrinal Pandey <mrinalmni@gmail.com> Link: https://lore.kernel.org/r/20200724131348.haz4ocxcferdcsgn@mrinalpandey Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* drivers: android: Fix a variable declaration coding style issueMrinal Pandey2020-07-291-0/+1
| | | | | | | | Add a blank line after variable declarations as suggested by checkpatch. Signed-off-by: Mrinal Pandey <mrinalmni@gmail.com> Link: https://lore.kernel.org/r/20200724131254.qxbvderrws36dzzq@mrinalpandey Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* binder: Prevent context manager from incrementing ref 0Jann Horn2020-07-291-1/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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. <https://syzkaller.appspot.com/bug?extid=09e05aba06723a94d43d>. 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 <tkjos@google.com> Signed-off-by: Jann Horn <jannh@google.com> Reviewed-by: Martijn Coenen <maco@android.com> Link: https://lore.kernel.org/r/20200727120424.1627555-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* binder: Don't use mmput() from shrinker function.Tetsuo Handa2020-07-231-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | 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 <syzbot+1068f09c44d151250c33@syzkaller.appspotmail.com> Reported-by: syzbot <syzbot+e5344baa319c9a96edec@syzkaller.appspotmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Michal Hocko <mhocko@suse.com> Acked-by: Todd Kjos <tkjos@google.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/4ba9adb2-43f5-2de0-22de-f6075c1fab50@i-love.sakura.ne.jp Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* binder: fix null deref of proc->contextTodd Kjos2020-06-231-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <christian.brauner@ubuntu.com> Signed-off-by: Todd Kjos <tkjos@google.com> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200622200715.114382-1-tkjos@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* treewide: replace '---help---' in Kconfig files with 'help'Masahiro Yamada2020-06-141-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | 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 <masahiroy@kernel.org>
* mmap locking API: convert mmap_sem API commentsMichel Lespinasse2020-06-091-2/+2
| | | | | | | | | | | | | | | | | | | | | | | Convert comments that reference old mmap_sem APIs to reference corresponding new mmap locking APIs instead. Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-12-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mmap locking API: use coccinelle to convert mmap_sem rwsem call sitesMichel Lespinasse2020-06-091-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* binderfs: remove redundant assignment to pointer ctxColin Ian King2020-04-231-1/+1
| | | | | | | | | | | | 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 <colin.king@canonical.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/r/20200402105000.506296-1-colin.king@canonical.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* binderfs: Fix binderfs.c selftest compilation warningTang Bin2020-04-231-1/+1
| | | | | | | | | | | | | | 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 <christian.brauner@ubuntu.com> Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com> Link: https://lore.kernel.org/r/20200411145151.5576-1-tangbin@cmss.chinamobile.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge 5.6-rc7 into char-misc-nextGreg Kroah-Hartman2020-03-231-0/+1
|\ | | | | | | | | | | We need the char/misc driver fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * binderfs: use refcount for binder control devices tooChristian Brauner2020-03-111-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Binderfs binder-control devices are cleaned up via binderfs_evict_inode too() which will use refcount_dec_and_test(). However, we missed to set the refcount for binderfs binder-control devices and so we underflowed when the binderfs instance got unmounted. Pretty obvious oversight and should have been part of the more general UAF fix. The good news is that having test cases (suprisingly) helps. Technically, we could detect that we're about to cleanup the binder-control dentry in binderfs_evict_inode() and then simply clean it up. But that makes the assumption that the binder driver itself will never make use of a binderfs binder-control device after the binderfs instance it belongs to has been unmounted and the superblock for it been destroyed. While it is unlikely to ever come to this let's be on the safe side. Performance-wise this also really doesn't matter since the binder-control device is only every really when creating the binderfs filesystem or creating additional binder devices. Both operations are pretty rare. Fixes: f0fe2c0f050d ("binder: prevent UAF for binderfs devices II") Link: https://lore.kernel.org/r/CA+G9fYusdfg7PMfC9Xce-xLT7NiyKSbgojpK35GOm=Pf9jXXrA@mail.gmail.com Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Cc: stable@vger.kernel.org Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Todd Kjos <tkjos@google.com> Link: https://lore.kernel.org/r/20200311105309.1742827-1-christian.brauner@ubuntu.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | binderfs: port to new mount apiChristian Brauner2020-03-191-96/+104
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <tkjos@google.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200313153427.141789-1-christian.brauner@ubuntu.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* binder: prevent UAF for binderfs devices IIChristian Brauner2020-03-033-18/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a necessary follow up to the first fix I proposed and we merged in 2669b8b0c79 ("binder: prevent UAF for binderfs devices"). I have been overly optimistic that the simple fix I proposed would work. But alas, ihold() + iput() won't work since the inodes won't survive the destruction of the superblock. So all we get with my prior fix is a different race with a tinier race-window but it doesn't solve the issue. Fwiw, the problem lies with generic_shutdown_super(). It even has this cozy Al-style comment: if (!list_empty(&sb->s_inodes)) { printk("VFS: Busy inodes after unmount of %s. " "Self-destruct in 5 seconds. Have a nice day...\n", sb->s_id); } On binder_release(), binder_defer_work(proc, BINDER_DEFERRED_RELEASE) is called which punts the actual cleanup operation to a workqueue. At some point, binder_deferred_func() will be called which will end up calling binder_deferred_release() which will retrieve and cleanup the binder_context attach to this struct binder_proc. If we trace back where this binder_context is attached to binder_proc we see that it is set in binder_open() and is taken from the struct binder_device it is associated with. This obviously assumes that the struct binder_device that context is attached to is _never_ freed. While that might be true for devtmpfs binder devices it is most certainly wrong for binderfs binder devices. So, assume binder_open() is called on a binderfs binder devices. We now stash away the struct binder_context associated with that struct binder_devices: proc->context = &binder_dev->context; /* binderfs stashes devices in i_private */ if (is_binderfs_device(nodp)) { binder_dev = nodp->i_private; info = nodp->i_sb->s_fs_info; binder_binderfs_dir_entry_proc = info->proc_log_dir; } else { . . . proc->context = &binder_dev->context; Now let's assume that the binderfs instance for that binder devices is shutdown via umount() and/or the mount namespace associated with it goes away. As long as there is still an fd open for that binderfs binder device things are fine. But let's assume we now close the last fd for that binderfs binder device. Now binder_release() is called and punts to the workqueue. Assume that the workqueue has quite a bit of stuff to do and doesn't get to cleaning up the struct binder_proc and the associated struct binder_context with it for that binderfs binder device right away. In the meantime, the VFS is killing the super block and is ultimately calling sb->evict_inode() which means it will call binderfs_evict_inode() which does: static void binderfs_evict_inode(struct inode *inode) { struct binder_device *device = inode->i_private; struct binderfs_info *info = BINDERFS_I(inode); clear_inode(inode); if (!S_ISCHR(inode->i_mode) || !device) return; mutex_lock(&binderfs_minors_mutex); --info->device_count; ida_free(&binderfs_minors, device->miscdev.minor); mutex_unlock(&binderfs_minors_mutex); kfree(device->context.name); kfree(device); } thereby freeing the struct binder_device including struct binder_context. Now the workqueue finally has time to get around to cleaning up struct binder_proc and is now trying to access the associate struct binder_context. Since it's already freed it will OOPs. Fix this by introducing a refounct on binder devices. This is an alternative fix to 51d8a7eca677 ("binder: prevent UAF read in print_binder_transaction_log_entry()"). Fixes: 3ad20fe393b3 ("binder: implement binderfs") Fixes: 2669b8b0c798 ("binder: prevent UAF for binderfs devices") Fixes: 03e2e07e3814 ("binder: Make transaction_log available in binderfs") Related : 51d8a7eca677 ("binder: prevent UAF read in print_binder_transaction_log_entry()") Cc: stable@vger.kernel.org Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Todd Kjos <tkjos@google.com> Link: https://lore.kernel.org/r/20200303164340.670054-1-christian.brauner@ubuntu.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* binder: prevent UAF for binderfs devicesChristian Brauner2020-03-032-1/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On binder_release(), binder_defer_work(proc, BINDER_DEFERRED_RELEASE) is called which punts the actual cleanup operation to a workqueue. At some point, binder_deferred_func() will be called which will end up calling binder_deferred_release() which will retrieve and cleanup the binder_context attach to this struct binder_proc. If we trace back where this binder_context is attached to binder_proc we see that it is set in binder_open() and is taken from the struct binder_device it is associated with. This obviously assumes that the struct binder_device that context is attached to is _never_ freed. While that might be true for devtmpfs binder devices it is most certainly wrong for binderfs binder devices. So, assume binder_open() is called on a binderfs binder devices. We now stash away the struct binder_context associated with that struct binder_devices: proc->context = &binder_dev->context; /* binderfs stashes devices in i_private */ if (is_binderfs_device(nodp)) { binder_dev = nodp->i_private; info = nodp->i_sb->s_fs_info; binder_binderfs_dir_entry_proc = info->proc_log_dir; } else { . . . proc->context = &binder_dev->context; Now let's assume that the binderfs instance for that binder devices is shutdown via umount() and/or the mount namespace associated with it goes away. As long as there is still an fd open for that binderfs binder device things are fine. But let's assume we now close the last fd for that binderfs binder device. Now binder_release() is called and punts to the workqueue. Assume that the workqueue has quite a bit of stuff to do and doesn't get to cleaning up the struct binder_proc and the associated struct binder_context with it for that binderfs binder device right away. In the meantime, the VFS is killing the super block and is ultimately calling sb->evict_inode() which means it will call binderfs_evict_inode() which does: static void binderfs_evict_inode(struct inode *inode) { struct binder_device *device = inode->i_private; struct binderfs_info *info = BINDERFS_I(inode); clear_inode(inode); if (!S_ISCHR(inode->i_mode) || !device) return; mutex_lock(&binderfs_minors_mutex); --info->device_count; ida_free(&binderfs_minors, device->miscdev.minor); mutex_unlock(&binderfs_minors_mutex); kfree(device->context.name); kfree(device); } thereby freeing the struct binder_device including struct binder_context. Now the workqueue finally has time to get around to cleaning up struct binder_proc and is now trying to access the associate struct binder_context. Since it's already freed it will OOPs. Fix this by holding an additional reference to the inode that is only released once the workqueue is done cleaning up struct binder_proc. This is an easy alternative to introducing separate refcounting on struct binder_device which we can always do later if it becomes necessary. This is an alternative fix to 51d8a7eca677 ("binder: prevent UAF read in print_binder_transaction_log_entry()"). Fixes: 3ad20fe393b3 ("binder: implement binderfs") Fixes: 03e2e07e3814 ("binder: Make transaction_log available in binderfs") Related : 51d8a7eca677 ("binder: prevent UAF read in print_binder_transaction_log_entry()") Cc: stable@vger.kernel.org Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Todd Kjos <tkjos@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge tag 'for-5.6/io_uring-vfs-2020-01-29' of git://git.kernel.dk/linux-blockLinus Torvalds2020-01-291-2/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull io_uring updates from Jens Axboe: - Support for various new opcodes (fallocate, openat, close, statx, fadvise, madvise, openat2, non-vectored read/write, send/recv, and epoll_ctl) - Faster ring quiesce for fileset updates - Optimizations for overflow condition checking - Support for max-sized clamping - Support for probing what opcodes are supported - Support for io-wq backend sharing between "sibling" rings - Support for registering personalities - Lots of little fixes and improvements * tag 'for-5.6/io_uring-vfs-2020-01-29' of git://git.kernel.dk/linux-block: (64 commits) io_uring: add support for epoll_ctl(2) eventpoll: support non-blocking do_epoll_ctl() calls eventpoll: abstract out epoll_ctl() handler io_uring: fix linked command file table usage io_uring: support using a registered personality for commands io_uring: allow registering credentials io_uring: add io-wq workqueue sharing io-wq: allow grabbing existing io-wq io_uring/io-wq: don't use static creds/mm assignments io-wq: make the io_wq ref counted io_uring: fix refcounting with batched allocations at OOM io_uring: add comment for drain_next io_uring: don't attempt to copy iovec for READ/WRITE io_uring: honor IOSQE_ASYNC for linked reqs io_uring: prep req when do IOSQE_ASYNC io_uring: use labeled array init in io_op_defs io_uring: optimise sqe-to-req flags translation io_uring: remove REQ_F_IO_DRAINED io_uring: file switch work needs to get flushed on exit io_uring: hide uring_fd in ctx ...
| * fs: move filp_close() outside of __close_fd_get_file()Jens Axboe2020-01-201-2/+4
| | | | | | | | | | | | | | Just one caller of this, and just use filp_close() there manually. This is important to allow async close/removal of the fd. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | binder: fix log spam for existing debugfs file creation.Martin Fuzzey2020-01-221-18/+19
|/ | | | | | | | | | | | | | | | | | | | | | Since commit 43e23b6c0b01 ("debugfs: log errors when something goes wrong") debugfs logs attempts to create existing files. However binder attempts to create multiple debugfs files with the same name when a single PID has multiple contexts, this leads to log spamming during an Android boot (17 such messages during boot on my system). Fix this by checking if we already know the PID and only create the debugfs entry for the first context per PID. Do the same thing for binderfs for symmetry. Signed-off-by: Martin Fuzzey <martin.fuzzey@flowbird.group> Acked-by: Todd Kjos <tkjos@google.com> Fixes: 43e23b6c0b01 ("debugfs: log errors when something goes wrong") Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/1578671054-5982-1-git-send-email-martin.fuzzey@flowbird.group Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* binder: fix incorrect calculation for num_validTodd Kjos2019-12-141-2/+2
| | | | | | | | | | | | | For BINDER_TYPE_PTR and BINDER_TYPE_FDA transactions, the num_valid local was calculated incorrectly causing the range check in binder_validate_ptr() to miss out-of-bounds offsets. Fixes: bde4a19fc04f ("binder: use userspace pointer as base of buffer space") Signed-off-by: Todd Kjos <tkjos@google.com> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20191213202531.55010-1-tkjos@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge tag 'compat-ioctl-5.5' of ↵Linus Torvalds2019-12-011-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground Pull removal of most of fs/compat_ioctl.c from Arnd Bergmann: "As part of the cleanup of some remaining y2038 issues, I came to fs/compat_ioctl.c, which still has a couple of commands that need support for time64_t. In completely unrelated work, I spent time on cleaning up parts of this file in the past, moving things out into drivers instead. After Al Viro reviewed an earlier version of this series and did a lot more of that cleanup, I decided to try to completely eliminate the rest of it and move it all into drivers. This series incorporates some of Al's work and many patches of my own, but in the end stops short of actually removing the last part, which is the scsi ioctl handlers. I have patches for those as well, but they need more testing or possibly a rewrite" * tag 'compat-ioctl-5.5' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground: (42 commits) scsi: sd: enable compat ioctls for sed-opal pktcdvd: add compat_ioctl handler compat_ioctl: move SG_GET_REQUEST_TABLE handling compat_ioctl: ppp: move simple commands into ppp_generic.c compat_ioctl: handle PPPIOCGIDLE for 64-bit time_t compat_ioctl: move PPPIOCSCOMPRESS to ppp_generic compat_ioctl: unify copy-in of ppp filters tty: handle compat PPP ioctls compat_ioctl: move SIOCOUTQ out of compat_ioctl.c compat_ioctl: handle SIOCOUTQNSD af_unix: add compat_ioctl support compat_ioctl: reimplement SG_IO handling compat_ioctl: move WDIOC handling into wdt drivers fs: compat_ioctl: move FITRIM emulation into file systems gfs2: add compat_ioctl support compat_ioctl: remove unused convert_in_user macro compat_ioctl: remove last RAID handling code compat_ioctl: remove /dev/raw ioctl translation compat_ioctl: remove PCI ioctl translation compat_ioctl: remove joystick ioctl translation ...
| * compat_ioctl: move more drivers to compat_ptr_ioctlArnd Bergmann2019-10-231-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The .ioctl and .compat_ioctl file operations have the same prototype so they can both point to the same function, which works great almost all the time when all the commands are compatible. One exception is the s390 architecture, where a compat pointer is only 31 bit wide, and converting it into a 64-bit pointer requires calling compat_ptr(). Most drivers here will never run in s390, but since we now have a generic helper for it, it's easy enough to use it consistently. I double-checked all these drivers to ensure that all ioctl arguments are used as pointers or are ignored, but are not interpreted as integer values. Acked-by: Jason Gunthorpe <jgg@mellanox.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: David Sterba <dsterba@suse.com> Acked-by: Darren Hart (VMware) <dvhart@infradead.org> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org> Acked-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* | binder: Handle start==NULL in binder_update_page_range()Jann Horn2019-11-141-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The old loop wouldn't stop when reaching `start` if `start==NULL`, instead continuing backwards to index -1 and crashing. Luckily you need to be highly privileged to map things at NULL, so it's not a big problem. Fix it by adjusting the loop so that the loop variable is always in bounds. This patch is deliberately minimal to simplify backporting, but IMO this function could use a refactor. The jump labels in the second loop body are horrible (the error gotos should be jumping to free_range instead), and both loops would look nicer if they just iterated upwards through indices. And the up_read()+mmput() shouldn't be duplicated like that. Cc: stable@vger.kernel.org Fixes: 457b9a6f09f0 ("Staging: android: add binder driver") Signed-off-by: Jann Horn <jannh@google.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/r/20191018205631.248274-3-jannh@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | binder: Prevent repeated use of ->mmap() via NULL mappingJann Horn2019-11-141-5/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | binder_alloc_mmap_handler() attempts to detect the use of ->mmap() on a binder_proc whose binder_alloc has already been initialized by checking whether alloc->buffer is non-zero. Before commit 880211667b20 ("binder: remove kernel vm_area for buffer space"), alloc->buffer was a kernel mapping address, which is always non-zero, but since that commit, it is a userspace mapping address. A sufficiently privileged user can map /dev/binder at NULL, tricking binder_alloc_mmap_handler() into assuming that the binder_proc has not been mapped yet. This leads to memory unsafety. Luckily, no context on Android has such privileges, and on a typical Linux desktop system, you need to be root to do that. Fix it by using the mapping size instead of the mapping address to distinguish the mapped case. A valid VMA can't have size zero. Fixes: 880211667b20 ("binder: remove kernel vm_area for buffer space") Cc: stable@vger.kernel.org Signed-off-by: Jann Horn <jannh@google.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/r/20191018205631.248274-2-jannh@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | binder: Fix race between mmap() and binder_alloc_print_pages()Jann Horn2019-11-141-8/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | binder_alloc_print_pages() iterates over alloc->pages[0..alloc->buffer_size-1] under alloc->mutex. binder_alloc_mmap_handler() writes alloc->pages and alloc->buffer_size without holding that lock, and even writes them before the last bailout point. Unfortunately we can't take the alloc->mutex in the ->mmap() handler because mmap_sem can be taken while alloc->mutex is held. So instead, we have to locklessly check whether the binder_alloc has been fully initialized with binder_alloc_get_vma(), like in binder_alloc_new_buf_locked(). Fixes: 8ef4665aa129 ("android: binder: Add page usage in binder stats") Cc: stable@vger.kernel.org Signed-off-by: Jann Horn <jannh@google.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/r/20191018205631.248274-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | Merge 5.4-rc5 into char-misc-nextGreg Kroah-Hartman2019-10-272-9/+4
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | We want the binder fix in here as well for testing and to work on top of. Also handles a merge issue in binder.c to help linux-next out Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | binder: Don't modify VMA bounds in ->mmap handlerJann Horn2019-10-172-9/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | binder_mmap() tries to prevent the creation of overly big binder mappings by silently truncating the size of the VMA to 4MiB. However, this violates the API contract of mmap(). If userspace attempts to create a large binder VMA, and later attempts to unmap that VMA, it will call munmap() on a range beyond the end of the VMA, which may have been allocated to another VMA in the meantime. This can lead to userspace memory corruption. The following sequence of calls leads to a segfault without this commit: int main(void) { int binder_fd = open("/dev/binder", O_RDWR); if (binder_fd == -1) err(1, "open binder"); void *binder_mapping = mmap(NULL, 0x800000UL, PROT_READ, MAP_SHARED, binder_fd, 0); if (binder_mapping == MAP_FAILED) err(1, "mmap binder"); void *data_mapping = mmap(NULL, 0x400000UL, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); if (data_mapping == MAP_FAILED) err(1, "mmap data"); munmap(binder_mapping, 0x800000UL); *(char*)data_mapping = 1; return 0; } Cc: stable@vger.kernel.org Signed-off-by: Jann Horn <jannh@google.com> Acked-by: Todd Kjos <tkjos@google.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/r/20191016150119.154756-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | binder: Remove incorrect comment about vm_insert_page() behaviorJann Horn2019-10-211-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | vm_insert_page() does increment the page refcount, and just to be sure, I've confirmed it by printing page_count(page[0].page_ptr) before and after vm_insert_page(). It's 1 before, 2 afterwards, as expected. Fixes: a145dd411eb2 ("VM: add "vm_insert_page()" function") Signed-off-by: Jann Horn <jannh@google.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/r/20191018153946.128584-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | binder: Use common definition of SZ_1KJann Horn2019-10-171-5/+1
|/ / | | | | | | | | | | | | | | | | | | SZ_1K has been defined in include/linux/sizes.h since v3.6. Get rid of the duplicate definition. Signed-off-by: Jann Horn <jannh@google.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/r/20191016150119.154756-2-jannh@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | binder: Fix comment headers on binder_alloc_prepare_to_free()Joel Fernandes (Google)2019-10-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | binder_alloc_buffer_lookup() doesn't exist and is named "binder_alloc_prepare_to_free()". Correct the code comments to reflect this. Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/r/20190930201250.139554-1-joel@joelfernandes.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | binder: prevent UAF read in print_binder_transaction_log_entry()Christian Brauner2019-10-102-2/+4
|/ | | | | | | | | | | | | | | | | | | | | When a binder transaction is initiated on a binder device coming from a binderfs instance, a pointer to the name of the binder device is stashed in the binder_transaction_log_entry's context_name member. Later on it is used to print the name in print_binder_transaction_log_entry(). By the time print_binder_transaction_log_entry() accesses context_name binderfs_evict_inode() might have already freed the associated memory thereby causing a UAF. Do the simple thing and prevent this by copying the name of the binder device instead of stashing a pointer to it. Reported-by: Jann Horn <jannh@google.com> Fixes: 03e2e07e3814 ("binder: Make transaction_log available in binderfs") Link: https://lore.kernel.org/r/CAG48ez14Q0-F8LqsvcNbyR2o6gPW8SHXsm4u5jmD9MpsteM2Tw@mail.gmail.com Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Acked-by: Todd Kjos <tkjos@google.com> Reviewed-by: Hridya Valsaraju <hridya@google.com> Link: https://lore.kernel.org/r/20191008130159.10161-1-christian.brauner@ubuntu.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* binder: Add binder_proc logging to binderfsHridya Valsaraju2019-09-043-39/+121
| | | | | | | | | | | | | | | | | | | Currently /sys/kernel/debug/binder/proc contains the debug data for every binder_proc instance. This patch makes this information also available in a binderfs instance mounted with a mount option "stats=global" in addition to debugfs. The patch does not affect the presence of the file in debugfs. If a binderfs instance is mounted at path /dev/binderfs, this file would be present at /dev/binderfs/binder_logs/proc. This change provides an alternate way to access this file when debugfs is not mounted. Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Hridya Valsaraju <hridya@google.com> Link: https://lore.kernel.org/r/20190903161655.107408-5-hridya@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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