user/sven/linux.git/fs/proc, branch v4.9.284

proc: Avoid mixing integer types in mem_rw()

2021-07-28T07:14:27Z

[ Upstream commit d238692b4b9f2c36e35af4c6e6f6da36184aeb3e ] Use size_t when capping the count argument received by mem_rw(). Since count is size_t, using min_t(int, ...) can lead to a negative value that will later be passed to access_remote_vm(), which can cause unexpected behavior. Since we are capping the value to at maximum PAGE_SIZE, the conversion from size_t to int when passing it to access_remote_vm() as "len" shouldn't be a problem. Link: https://lkml.kernel.org/r/20210512125215.3348316-1-marcelo.cerri@canonical.com Reviewed-by: David Disseldorp Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Marcelo Henrique Cerri Cc: Alexey Dobriyan Cc: Souza Cascardo Cc: Christian Brauner Cc: Michel Lespinasse Cc: Helge Deller Cc: Oleg Nesterov Cc: Lorenzo Stoakes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

proc: only require mm_struct for writing

2021-06-16T09:36:36Z

commit 94f0b2d4a1d0c52035aef425da5e022bd2cb1c71 upstream. Commit 591a22c14d3f ("proc: Track /proc/$pid/attr/ opener mm_struct") we started using __mem_open() to track the mm_struct at open-time, so that we could then check it for writes. But that also ended up making the permission checks at open time much stricter - and not just for writes, but for reads too. And that in turn caused a regression for at least Fedora 29, where NIC interfaces fail to start when using NetworkManager. Since only the write side wanted the mm_struct test, ignore any failures by __mem_open() at open time, leaving reads unaffected. The write() time verification of the mm_struct pointer will then catch the failure case because a NULL pointer will not match a valid 'current->mm'. Link: https://lore.kernel.org/netdev/YMjTlp2FSJYvoyFa@unreal/ Fixes: 591a22c14d3f ("proc: Track /proc/$pid/attr/ opener mm_struct") Reported-and-tested-by: Leon Romanovsky Cc: Kees Cook Cc: Christian Brauner Cc: Andrea Righi Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

proc: Track /proc/$pid/attr/ opener mm_struct

2021-06-16T09:36:32Z

commit 591a22c14d3f45cc38bd1931c593c221df2f1881 upstream. Commit bfb819ea20ce ("proc: Check /proc/$pid/attr/ writes against file opener") tried to make sure that there could not be a confusion between the opener of a /proc/$pid/attr/ file and the writer. It used struct cred to make sure the privileges didn't change. However, there were existing cases where a more privileged thread was passing the opened fd to a differently privileged thread (during container setup). Instead, use mm_struct to track whether the opener and writer are still the same process. (This is what several other proc files already do, though for different reasons.) Reported-by: Christian Brauner Reported-by: Andrea Righi Tested-by: Andrea Righi Fixes: bfb819ea20ce ("proc: Check /proc/$pid/attr/ writes against file opener") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

proc: Check /proc/$pid/attr/ writes against file opener

2021-06-03T06:23:27Z

commit bfb819ea20ce8bbeeba17e1a6418bf8bda91fc28 upstream. Fix another "confused deputy" weakness[1]. Writes to /proc/$pid/attr/ files need to check the opener credentials, since these fds do not transition state across execve(). Without this, it is possible to trick another process (which may have different credentials) to write to its own /proc/$pid/attr/ files, leading to unexpected and possibly exploitable behaviors. [1] https://www.kernel.org/doc/html/latest/security/credentials.html?highlight=confused#open-file-credentials Fixes: 1da177e4c3f41 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm: add cond_resched() in gather_pte_stats()

2021-04-16T09:59:09Z

commit a66c0410b97c07a5708881198528ce724f7a3226 upstream. The other pagetable walks in task_mmu.c have a cond_resched() after walking their ptes: add a cond_resched() in gather_pte_stats() too, for reading /proc//numa_maps. Only pagemap_pmd_range() has a cond_resched() in its (unusually expensive) pmd_trans_huge case: more should probably be added, but leave them unchanged for now. Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1612052157400.13021@eggly.anvils Signed-off-by: Hugh Dickins Acked-by: Michal Hocko Cc: David Rientjes Cc: Gerald Schaefer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Reported-by: Chen si Signed-off-by: Baoyou Xie Signed-off-by: Wen Yang Signed-off-by: Zijiang Huang Signed-off-by: Greg Kroah-Hartman

proc: don't allow async path resolution of /proc/self components

2020-12-02T07:31:26Z

[ Upstream commit 8d4c3e76e3be11a64df95ddee52e99092d42fc19 ] If this is attempted by a kthread, then return -EOPNOTSUPP as we don't currently support that. Once we can get task_pid_ptr() doing the right thing, then this can go away again. Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

proc: Use new_inode not new_inode_pseudo

2020-06-20T08:24:11Z

commit ef1548adada51a2f32ed7faef50aa465e1b4c5da upstream. Recently syzbot reported that unmounting proc when there is an ongoing inotify watch on the root directory of proc could result in a use after free when the watch is removed after the unmount of proc when the watcher exits. Commit 69879c01a0c3 ("proc: Remove the now unnecessary internal mount of proc") made it easier to unmount proc and allowed syzbot to see the problem, but looking at the code it has been around for a long time. Looking at the code the fsnotify watch should have been removed by fsnotify_sb_delete in generic_shutdown_super. Unfortunately the inode was allocated with new_inode_pseudo instead of new_inode so the inode was not on the sb->s_inodes list. Which prevented fsnotify_unmount_inodes from finding the inode and removing the watch as well as made it so the "VFS: Busy inodes after unmount" warning could not find the inodes to warn about them. Make all of the inodes in proc visible to generic_shutdown_super, and fsnotify_sb_delete by using new_inode instead of new_inode_pseudo. The only functional difference is that new_inode places the inodes on the sb->s_inodes list. I wrote a small test program and I can verify that without changes it can trigger this issue, and by replacing new_inode_pseudo with new_inode the issues goes away. Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/000000000000d788c905a7dfa3f4@google.com Reported-by: syzbot+7d2debdcdb3cb93c1e5e@syzkaller.appspotmail.com Fixes: 0097875bd415 ("proc: Implement /proc/thread-self to point at the directory of the current thread") Fixes: 021ada7dff22 ("procfs: switch /proc/self away from proc_dir_entry") Fixes: 51f0885e5415 ("vfs,proc: guarantee unique inodes in /proc") Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman

vmalloc: fix remap_vmalloc_range() bounds checks

2020-05-02T15:23:10Z

commit bdebd6a2831b6fab69eb85cee74a8ba77f1a1cc2 upstream. remap_vmalloc_range() has had various issues with the bounds checks it promises to perform ("This function checks that addr is a valid vmalloc'ed area, and that it is big enough to cover the vma") over time, e.g.: - not detecting pgoff< Signed-off-by: Andrew Morton Cc: stable@vger.kernel.org Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Martin KaFai Lau Cc: Song Liu Cc: Yonghong Song Cc: Andrii Nakryiko Cc: John Fastabend Cc: KP Singh Link: http://lkml.kernel.org/r/20200415222312.236431-1-jannh@google.com Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

proc/vmcore: Fix i386 build error of missing copy_oldmem_page_encrypted()

2019-11-25T08:53:44Z

[ Upstream commit cf089611f4c446285046fcd426d90c18f37d2905 ] Lianbo reported a build error with a particular 32-bit config, see Link below for details. Provide a weak copy_oldmem_page_encrypted() function which architectures can override, in the same manner other functionality in that file is supplied. Reported-by: Lianbo Jiang Signed-off-by: Borislav Petkov CC: x86@kernel.org Link: http://lkml.kernel.org/r/710b9d95-2f70-eadf-c4a1-c3dc80ee4ebb@redhat.com Signed-off-by: Sasha Levin

coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping

2019-08-06T16:29:41Z

commit 04f5866e41fb70690e28397487d8bd8eea7d712a upstream. The core dumping code has always run without holding the mmap_sem for writing, despite that is the only way to ensure that the entire vma layout will not change from under it. Only using some signal serialization on the processes belonging to the mm is not nearly enough. This was pointed out earlier. For example in Hugh's post from Jul 2017: https://lkml.kernel.org/r/alpine.LSU.2.11.1707191716030.2055@eggly.anvils "Not strictly relevant here, but a related note: I was very surprised to discover, only quite recently, how handle_mm_fault() may be called without down_read(mmap_sem) - when core dumping. That seems a misguided optimization to me, which would also be nice to correct" In particular because the growsdown and growsup can move the vm_start/vm_end the various loops the core dump does around the vma will not be consistent if page faults can happen concurrently. Pretty much all users calling mmget_not_zero()/get_task_mm() and then taking the mmap_sem had the potential to introduce unexpected side effects in the core dumping code. Adding mmap_sem for writing around the ->core_dump invocation is a viable long term fix, but it requires removing all copy user and page faults and to replace them with get_dump_page() for all binary formats which is not suitable as a short term fix. For the time being this solution manually covers the places that can confuse the core dump either by altering the vma layout or the vma flags while it runs. Once ->core_dump runs under mmap_sem for writing the function mmget_still_valid() can be dropped. Allowing mmap_sem protected sections to run in parallel with the coredump provides some minor parallelism advantage to the swapoff code (which seems to be safe enough by never mangling any vma field and can keep doing swapins in parallel to the core dumping) and to some other corner case. In order to facilitate the backporting I added "Fixes: 86039bd3b4e6" however the side effect of this same race condition in /proc/pid/mem should be reproducible since before 2.6.12-rc2 so I couldn't add any other "Fixes:" because there's no hash beyond the git genesis commit. Because find_extend_vma() is the only location outside of the process context that could modify the "mm" structures under mmap_sem for reading, by adding the mmget_still_valid() check to it, all other cases that take the mmap_sem for reading don't need the new check after mmget_not_zero()/get_task_mm(). The expand_stack() in page fault context also doesn't need the new check, because all tasks under core dumping are frozen. Link: http://lkml.kernel.org/r/20190325224949.11068-1-aarcange@redhat.com Fixes: 86039bd3b4e6 ("userfaultfd: add new syscall to provide memory externalization") Signed-off-by: Andrea Arcangeli Reported-by: Jann Horn Suggested-by: Oleg Nesterov Acked-by: Peter Xu Reviewed-by: Mike Rapoport Reviewed-by: Oleg Nesterov Reviewed-by: Jann Horn Acked-by: Jason Gunthorpe Acked-by: Michal Hocko Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [akaher@vmware.com: stable 4.9 backport - handle binder_update_page_range - mhocko@suse.com] Signed-off-by: Ajay Kaher Signed-off-by: Greg Kroah-Hartman