Sysbot has reported a warning where a kmalloc() attempt exceeds the maximum limit. This has been identified as corruption of the xattr_ids count when reading the xattr id lookup table. This patch adds a number of additional sanity checks to detect this corruption and others. 1. It checks for a corrupted xattr index read from the inode. This could be because the metadata block is uncompressed, or because the "compression" bit has been corrupted (turning a compressed block into an uncompressed block). This would cause an out of bounds read. 2. It checks against corruption of the xattr_ids count. This can either lead to the above kmalloc failure, or a smaller than expected table to be read. 3. It checks the contents of the index table for corruption. [phillip@squashfs.org.uk: fix checkpatch issue] Link: https://lkml.kernel.org/r/270245655.754655.1612770082682@webmail.123-reg.co.uk Link: https://lkml.kernel.org/r/20210204130249.4495-5-phillip@squashfs.org.uk Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> Reported-by: syzbot+2ccea6339d368360800d@syzkaller.appspotmail.com Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Sysbot has reported an "slab-out-of-bounds read" error which has been identified as being caused by a corrupted "ino_num" value read from the inode. This could be because the metadata block is uncompressed, or because the "compression" bit has been corrupted (turning a compressed block into an uncompressed block). This patch adds additional sanity checks to detect this, and the following corruption. 1. It checks against corruption of the inodes count. This can either lead to a larger table to be read, or a smaller than expected table to be read. In the case of a too large inodes count, this would often have been trapped by the existing sanity checks, but this patch introduces a more exact check, which can identify too small values. 2. It checks the contents of the index table for corruption. [phillip@squashfs.org.uk: fix checkpatch issue] Link: https://lkml.kernel.org/r/527909353.754618.1612769948607@webmail.123-reg.co.uk Link: https://lkml.kernel.org/r/20210204130249.4495-4-phillip@squashfs.org.uk Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> Reported-by: syzbot+04419e3ff19d2970ea28@syzkaller.appspotmail.com Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Sysbot has reported a number of "slab-out-of-bounds reads" and "use-after-free read" errors which has been identified as being caused by a corrupted index value read from the inode. This could be because the metadata block is uncompressed, or because the "compression" bit has been corrupted (turning a compressed block into an uncompressed block). This patch adds additional sanity checks to detect this, and the following corruption. 1. It checks against corruption of the ids count. This can either lead to a larger table to be read, or a smaller than expected table to be read. In the case of a too large ids count, this would often have been trapped by the existing sanity checks, but this patch introduces a more exact check, which can identify too small values. 2. It checks the contents of the index table for corruption. Link: https://lkml.kernel.org/r/20210204130249.4495-3-phillip@squashfs.org.uk Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> Reported-by: syzbot+b06d57ba83f604522af2@syzkaller.appspotmail.com Reported-by: syzbot+c021ba012da41ee9807c@syzkaller.appspotmail.com Reported-by: syzbot+5024636e8b5fd19f0f19@syzkaller.appspotmail.com Reported-by: syzbot+bcbc661df46657d0fa4f@syzkaller.appspotmail.com Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Squashfs: fix BIO migration regression and add sanity checks".
Patch [1/4] fixes a regression introduced by the "migrate from
ll_rw_block usage to BIO" patch, which has produced a number of
Sysbot/Syzkaller reports.
Patches [2/4], [3/4], and [4/4] fix a number of filesystem corruption
issues which have produced Sysbot reports in the id, inode and xattr
lookup code.
Each patch has been tested against the Sysbot reproducers using the
given kernel configuration. They have the appropriate "Reported-by:"
lines added.
Additionally, all of the reproducer filesystems are indirectly fixed by
patch [4/4] due to the fact they all have xattr corruption which is now
detected there.
Additional testing with other configurations and architectures (32bit,
big endian), and normal filesystems has also been done to trap any
inadvertent regressions caused by the additional sanity checks.
This patch (of 4):
This is a regression introduced by the patch "migrate from ll_rw_block
usage to BIO".
Sysbot/Syskaller has reported a number of "out of bounds writes" and
"unable to handle kernel paging request in squashfs_decompress" errors
which have been identified as a regression introduced by the above
patch.
Specifically, the patch removed the following sanity check
if (length < 0 || length > output->length ||
(index + length) > msblk->bytes_used)
This check did two things:
1. It ensured any reads were not beyond the end of the filesystem
2. It ensured that the "length" field read from the filesystem
was within the expected maximum length. Without this any
corrupted values can over-run allocated buffers.
Link: https://lkml.kernel.org/r/20210204130249.4495-1-phillip@squashfs.org.uk
Link: https://lkml.kernel.org/r/20210204130249.4495-2-phillip@squashfs.org.uk
Fixes: 93e72b3c612adc ("squashfs: migrate from ll_rw_block usage to BIO")
Reported-by: syzbot+6fba78f99b9afd4b5634@syzkaller.appspotmail.com
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Cc: Philippe Liard <pliard@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull misc vfs updates from Al Viro: "Assorted stuff all over the place (the largest group here is Christoph's stat cleanups)" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: remove KSTAT_QUERY_FLAGS fs: remove vfs_stat_set_lookup_flags fs: move vfs_fstatat out of line fs: implement vfs_stat and vfs_lstat in terms of vfs_fstatat fs: remove vfs_statx_fd fs: omfs: use kmemdup() rather than kmalloc+memcpy [PATCH] reduce boilerplate in fsid handling fs: Remove duplicated flag O_NDELAY occurring twice in VALID_OPEN_FLAGS selftests: mount: add nosymfollow tests Add a "nosymfollow" mount option.
Get rid of boilerplate in most of ->statfs() instances... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This is a regression introduced by the patch "migrate from ll_rw_block
usage to BIO".
Bio_alloc() is limited to 256 pages (1 Mbyte). This can cause a failure
when reading 1 Mbyte block filesystems. The problem is a datablock can be
fully (or almost uncompressed), requiring 256 pages, but, because blocks
are not aligned to page boundaries, it may require 257 pages to read.
Bio_kmalloc() can handle 1024 pages, and so use this for the edge
condition.
Fixes: 93e72b3c612a ("squashfs: migrate from ll_rw_block usage to BIO")
Reported-by: Nicolas Prochazka <nicolas.prochazka@gmail.com>
Reported-by: Tomoatsu Shimada <shimada@walbrix.com>
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Cc: Philippe Liard <pliard@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Adrien Schildknecht <adrien+dev@schischi.me>
Cc: Daniel Rosenberg <drosen@google.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200815035637.15319-1-phillip@squashfs.org.uk
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a regression introduced by the "migrate from ll_rw_block usage
to BIO" patch.
Squashfs packs structures on byte boundaries, and due to that the length
field (of the metadata block) may not be fully in the current block.
The new code rewrote and introduced a faulty check for that edge case.
Fixes: 93e72b3c612adcaca1 ("squashfs: migrate from ll_rw_block usage to BIO")
Reported-by: Bernd Amend <bernd.amend@gmail.com>
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Adrien Schildknecht <adrien+dev@schischi.me>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Daniel Rosenberg <drosen@google.com>
Link: http://lkml.kernel.org/r/20200717195536.16069-1-phillip@squashfs.org.uk
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://github.com/KSPP/linux/issues/21 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Merge updates from Andrew Morton: "A few little subsystems and a start of a lot of MM patches. Subsystems affected by this patch series: squashfs, ocfs2, parisc, vfs. With mm subsystems: slab-generic, slub, debug, pagecache, gup, swap, memcg, pagemap, memory-failure, vmalloc, kasan" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (128 commits) kasan: move kasan_report() into report.c mm/mm_init.c: report kasan-tag information stored in page->flags ubsan: entirely disable alignment checks under UBSAN_TRAP kasan: fix clang compilation warning due to stack protector x86/mm: remove vmalloc faulting mm: remove vmalloc_sync_(un)mappings() x86/mm/32: implement arch_sync_kernel_mappings() x86/mm/64: implement arch_sync_kernel_mappings() mm/ioremap: track which page-table levels were modified mm/vmalloc: track which page-table levels were modified mm: add functions to track page directory modifications s390: use __vmalloc_node in stack_alloc powerpc: use __vmalloc_node in alloc_vm_stack arm64: use __vmalloc_node in arch_alloc_vmap_stack mm: remove vmalloc_user_node_flags mm: switch the test_vmalloc module to use __vmalloc_node mm: remove __vmalloc_node_flags_caller mm: remove both instances of __vmalloc_node_flags mm: remove the prot argument to __vmalloc_node mm: remove the pgprot argument to __vmalloc ...