kernel/fs, branch linux-3.2.y

fs: Teach path_connected to handle nfs filesystems with multiple roots.

2018-05-31T23:30:22Z

commit 95dd77580ccd66a0da96e6d4696945b8cea39431 upstream. On nfsv2 and nfsv3 the nfs server can export subsets of the same filesystem and report the same filesystem identifier, so that the nfs client can know they are the same filesystem. The subsets can be from disjoint directory trees. The nfsv2 and nfsv3 filesystems provides no way to find the common root of all directory trees exported form the server with the same filesystem identifier. The practical result is that in struct super s_root for nfs s_root is not necessarily the root of the filesystem. The nfs mount code sets s_root to the root of the first subset of the nfs filesystem that the kernel mounts. This effects the dcache invalidation code in generic_shutdown_super currently called shrunk_dcache_for_umount and that code for years has gone through an additional list of dentries that might be dentry trees that need to be freed to accomodate nfs. When I wrote path_connected I did not realize nfs was so special, and it's hueristic for avoiding calling is_subdir can fail. The practical case where this fails is when there is a move of a directory from the subtree exposed by one nfs mount to the subtree exposed by another nfs mount. This move can happen either locally or remotely. With the remote case requiring that the move directory be cached before the move and that after the move someone walks the path to where the move directory now exists and in so doing causes the already cached directory to be moved in the dcache through the magic of d_splice_alias. If someone whose working directory is in the move directory or a subdirectory and now starts calling .. from the initial mount of nfs (where s_root == mnt_root), then path_connected as a heuristic will not bother with the is_subdir check. As s_root really is not the root of the nfs filesystem this heuristic is wrong, and the path may actually not be connected and path_connected can fail. The is_subdir function might be cheap enough that we can call it unconditionally. Verifying that will take some benchmarking and the result may not be the same on all kernels this fix needs to be backported to. So I am avoiding that for now. Filesystems with snapshots such as nilfs and btrfs do something similar. But as the directory tree of the snapshots are disjoint from one another and from the main directory tree rename won't move things between them and this problem will not occur. Reported-by: Al Viro Fixes: 397d425dc26d ("vfs: Test for and handle paths that are unreachable from their mnt_root") Signed-off-by: "Eric W. Biederman" Signed-off-by: Al Viro [bwh: Backported to 3.2: - Add the super_block::s_iflags field - Adjust context] Signed-off-by: Ben Hutchings

Btrfs: fix extent state leak from tree log

2018-05-31T23:30:12Z

commit 55237a5f2431a72435e3ed39e4306e973c0446b7 upstream. It's possible that btrfs_sync_log() bails out after one of the two btrfs_write_marked_extents() which convert extent state's state bit into EXTENT_NEED_WAIT from EXTENT_DIRTY/EXTENT_NEW, however only EXTENT_DIRTY and EXTENT_NEW are searched by free_log_tree() so that those extent states with EXTENT_NEED_WAIT lead to memory leak. Signed-off-by: Liu Bo Reviewed-by: Josef Bacik Signed-off-by: David Sterba [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

jffs2: Fix use-after-free bug in jffs2_iget()'s error handling path

2018-05-31T23:30:10Z

commit 5bdd0c6f89fba430e18d636493398389dadc3b17 upstream. If jffs2_iget() fails for a newly-allocated inode, jffs2_do_clear_inode() can get called twice in the error handling path, the first call in jffs2_iget() itself and the second through iget_failed(). This can result to a use-after-free error in the second jffs2_do_clear_inode() call, such as shown by the oops below wherein the second jffs2_do_clear_inode() call was trying to free node fragments that were already freed in the first jffs2_do_clear_inode() call. [ 78.178860] jffs2: error: (1904) jffs2_do_read_inode_internal: CRC failed for read_inode of inode 24 at physical location 0x1fc00c [ 78.178914] Unable to handle kernel paging request at virtual address 6b6b6b6b6b6b6b7b [ 78.185871] pgd = ffffffc03a567000 [ 78.188794] [6b6b6b6b6b6b6b7b] *pgd=0000000000000000, *pud=0000000000000000 [ 78.194968] Internal error: Oops: 96000004 [#1] PREEMPT SMP ... [ 78.513147] PC is at rb_first_postorder+0xc/0x28 [ 78.516503] LR is at jffs2_kill_fragtree+0x28/0x90 [jffs2] [ 78.520672] pc : [] lr : [] pstate: 60000105 [ 78.526757] sp : ffffff800cea38f0 [ 78.528753] x29: ffffff800cea38f0 x28: ffffffc01f3f8e80 [ 78.532754] x27: 0000000000000000 x26: ffffff800cea3c70 [ 78.536756] x25: 00000000dc67c8ae x24: ffffffc033d6945d [ 78.540759] x23: ffffffc036811740 x22: ffffff800891a5b8 [ 78.544760] x21: 0000000000000000 x20: 0000000000000000 [ 78.548762] x19: ffffffc037d48910 x18: ffffff800891a588 [ 78.552764] x17: 0000000000000800 x16: 0000000000000c00 [ 78.556766] x15: 0000000000000010 x14: 6f2065646f6e695f [ 78.560767] x13: 6461657220726f66 x12: 2064656c69616620 [ 78.564769] x11: 435243203a6c616e x10: 7265746e695f6564 [ 78.568771] x9 : 6f6e695f64616572 x8 : ffffffc037974038 [ 78.572774] x7 : bbbbbbbbbbbbbbbb x6 : 0000000000000008 [ 78.576775] x5 : 002f91d85bd44a2f x4 : 0000000000000000 [ 78.580777] x3 : 0000000000000000 x2 : 000000403755e000 [ 78.584779] x1 : 6b6b6b6b6b6b6b6b x0 : 6b6b6b6b6b6b6b6b ... [ 79.038551] [] rb_first_postorder+0xc/0x28 [ 79.042962] [] jffs2_do_clear_inode+0x88/0x100 [jffs2] [ 79.048395] [] jffs2_evict_inode+0x3c/0x48 [jffs2] [ 79.053443] [] evict+0xb0/0x168 [ 79.056835] [] iput+0x1c0/0x200 [ 79.060228] [] iget_failed+0x30/0x3c [ 79.064097] [] jffs2_iget+0x2d8/0x360 [jffs2] [ 79.068740] [] jffs2_lookup+0xe8/0x130 [jffs2] [ 79.073434] [] lookup_slow+0x118/0x190 [ 79.077435] [] walk_component+0xfc/0x28c [ 79.081610] [] path_lookupat+0x84/0x108 [ 79.085699] [] filename_lookup+0x88/0x100 [ 79.089960] [] user_path_at_empty+0x58/0x6c [ 79.094396] [] vfs_statx+0xa4/0x114 [ 79.098138] [] SyS_newfstatat+0x58/0x98 [ 79.102227] [] __sys_trace_return+0x0/0x4 [ 79.106489] Code: d65f03c0 f9400001 b40000e1 aa0103e0 (f9400821) The jffs2_do_clear_inode() call in jffs2_iget() is unnecessary since iget_failed() will eventually call jffs2_do_clear_inode() if needed, so just remove it. Fixes: 5451f79f5f81 ("iget: stop JFFS2 from using iget() and read_inode()") Reviewed-by: Richard Weinberger Signed-off-by: Jake Daryll Obina Signed-off-by: Al Viro Signed-off-by: Ben Hutchings

cifs: Fix missing put_xid in cifs_file_strict_mmap

2018-05-31T23:30:10Z

commit f04a703c3d613845ae3141bfaf223489de8ab3eb upstream. If cifs_zap_mapping() returned an error, we would return without putting the xid that we got earlier. Restructure cifs_file_strict_mmap() and cifs_file_mmap() to be more similar to each other and have a single point of return that always puts the xid. Signed-off-by: Matthew Wilcox Signed-off-by: Steve French [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

ext4: save error to disk in __ext4_grp_locked_error()

2018-05-31T23:30:06Z

commit 06f29cc81f0350261f59643a505010531130eea0 upstream. In the function __ext4_grp_locked_error(), __save_error_info() is called to save error info in super block block, but does not sync that information to disk to info the subsequence fsck after reboot. This patch writes the error information to disk. After this patch, I think there is no obvious EXT4 error handle branches which leads to "Remounting filesystem read-only" will leave the disk partition miss the subsequence fsck. Signed-off-by: Zhouyi Zhou Signed-off-by: Theodore Ts'o Signed-off-by: Ben Hutchings

staging: ncpfs: memory corruption in ncp_read_kernel()

2018-05-31T23:30:03Z

commit 4c41aa24baa4ed338241d05494f2c595c885af8f upstream. If the server is malicious then *bytes_read could be larger than the size of the "target" buffer. It would lead to memory corruption when we do the memcpy(). Reported-by: Dr Silvio Cesare of InfoSect Signed-off-by: Dan Carpenter Signed-off-by: Greg Kroah-Hartman [carnil: backport to 4.9: Files renamed from drivers/staging/ncpfs/ncplib_kernel.c to fs/ncpfs/ncplib_kernel.c] Signed-off-by: Ben Hutchings

hugetlbfs: check for pgoff value overflow

2018-05-31T23:30:03Z

commit 63489f8e821144000e0bdca7e65a8d1cc23a7ee7 upstream. A vma with vm_pgoff large enough to overflow a loff_t type when converted to a byte offset can be passed via the remap_file_pages system call. The hugetlbfs mmap routine uses the byte offset to calculate reservations and file size. A sequence such as: mmap(0x20a00000, 0x600000, 0, 0x66033, -1, 0); remap_file_pages(0x20a00000, 0x600000, 0, 0x20000000000000, 0); will result in the following when task exits/file closed, kernel BUG at mm/hugetlb.c:749! Call Trace: hugetlbfs_evict_inode+0x2f/0x40 evict+0xcb/0x190 __dentry_kill+0xcb/0x150 __fput+0x164/0x1e0 task_work_run+0x84/0xa0 exit_to_usermode_loop+0x7d/0x80 do_syscall_64+0x18b/0x190 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 The overflowed pgoff value causes hugetlbfs to try to set up a mapping with a negative range (end < start) that leaves invalid state which causes the BUG. The previous overflow fix to this code was incomplete and did not take the remap_file_pages system call into account. [mike.kravetz@oracle.com: v3] Link: http://lkml.kernel.org/r/20180309002726.7248-1-mike.kravetz@oracle.com [akpm@linux-foundation.org: include mmdebug.h] [akpm@linux-foundation.org: fix -ve left shift count on sh] Link: http://lkml.kernel.org/r/20180308210502.15952-1-mike.kravetz@oracle.com Fixes: 045c7a3f53d9 ("hugetlbfs: fix offset overflow in hugetlbfs mmap") Signed-off-by: Mike Kravetz Reported-by: Nic Losby Acked-by: Michal Hocko Cc: "Kirill A . Shutemov" Cc: Yisheng Xie Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: - Use a conditional WARN() instead of VM_WARN() - Adjust context] Signed-off-by: Ben Hutchings

hugetlbfs: fix offset overflow in hugetlbfs mmap

2018-05-31T23:30:02Z

commit 045c7a3f53d9403b62d396b6d051c4be5044cdb4 upstream. If mmap() maps a file, it can be passed an offset into the file at which the mapping is to start. Offset could be a negative value when represented as a loff_t. The offset plus length will be used to update the file size (i_size) which is also a loff_t. Validate the value of offset and offset + length to make sure they do not overflow and appear as negative. Found by syzcaller with commit ff8c0c53c475 ("mm/hugetlb.c: don't call region_abort if region_chg fails") applied. Prior to this commit, the overflow would still occur but we would luckily return ENOMEM. To reproduce: mmap(0, 0x2000, 0, 0x40021, 0xffffffffffffffffULL, 0x8000000000000000ULL); Resulted in, kernel BUG at mm/hugetlb.c:742! Call Trace: hugetlbfs_evict_inode+0x80/0xa0 evict+0x24a/0x620 iput+0x48f/0x8c0 dentry_unlink_inode+0x31f/0x4d0 __dentry_kill+0x292/0x5e0 dput+0x730/0x830 __fput+0x438/0x720 ____fput+0x1a/0x20 task_work_run+0xfe/0x180 exit_to_usermode_loop+0x133/0x150 syscall_return_slowpath+0x184/0x1c0 entry_SYSCALL_64_fastpath+0xab/0xad Fixes: ff8c0c53c475 ("mm/hugetlb.c: don't call region_abort if region_chg fails") Link: http://lkml.kernel.org/r/1491951118-30678-1-git-send-email-mike.kravetz@oracle.com Reported-by: Vegard Nossum Signed-off-by: Mike Kravetz Acked-by: Hillf Danton Cc: Dmitry Vyukov Cc: Michal Hocko Cc: "Kirill A . Shutemov" Cc: Andrey Ryabinin Cc: Naoya Horiguchi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

ext4: fix bitmap position validation

2018-05-31T23:30:01Z

commit 22be37acce25d66ecf6403fc8f44df9c5ded2372 upstream. Currently in ext4_valid_block_bitmap() we expect the bitmap to be positioned anywhere between 0 and s_blocksize clusters, but that's wrong because the bitmap can be placed anywhere in the block group. This causes false positives when validating bitmaps on perfectly valid file system layouts. Fix it by checking whether the bitmap is within the group boundary. The problem can be reproduced using the following mkfs -t ext3 -E stride=256 /dev/vdb1 mount /dev/vdb1 /mnt/test cd /mnt/test wget https://cdn.kernel.org/pub/linux/kernel/v4.x/linux-4.16.3.tar.xz tar xf linux-4.16.3.tar.xz This will result in the warnings in the logs EXT4-fs error (device vdb1): ext4_validate_block_bitmap:399: comm tar: bg 84: block 2774529: invalid block bitmap [ Changed slightly for clarity and to not drop a overflow test -- TYT ] Signed-off-by: Lukas Czerner Signed-off-by: Theodore Ts'o Reported-by: Ilya Dryomov Fixes: 7dac4a1726a9 ("ext4: add validity checks for bitmap block numbers") [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

ext4: add validity checks for bitmap block numbers

2018-05-31T23:30:01Z

commit 7dac4a1726a9c64a517d595c40e95e2d0d135f6f upstream. An privileged attacker can cause a crash by mounting a crafted ext4 image which triggers a out-of-bounds read in the function ext4_valid_block_bitmap() in fs/ext4/balloc.c. This issue has been assigned CVE-2018-1093. BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=199181 BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1560782 Reported-by: Wen Xu Signed-off-by: Theodore Ts'o [bwh: Backported to 3.2: - In ext4_valid_block_bitmap(), goto err_out on error - In ext4_read_{block,inode}_bitmap(), return NULL on error - Adjust context] Signed-off-by: Ben Hutchings