Minimal supplement to upstream Kernel Self Protection Project changes. Features already provided by SELinux + Yama and archs other than multiarch arm64 / x86_64 aren't in scope. Only tags have stable history. Shared IRC channel with KSPP: irc.libera.chat #linux-hardening
9e6c08d4a8
So we don't check the validity of records as we walk the btree. When there are corrupt records in the free space btree (e.g. zero startblock/length or beyond EOAG) we just blindly use it and things go bad from there. That leads to assert failures on debug kernels like this: XFS: Assertion failed: fs_is_ok, file: fs/xfs/libxfs/xfs_alloc.c, line: 450 .... Call Trace: xfs_alloc_fixup_trees+0x368/0x5c0 xfs_alloc_ag_vextent_near+0x79a/0xe20 xfs_alloc_ag_vextent+0x1d3/0x330 xfs_alloc_vextent+0x5e9/0x870 Or crashes like this: XFS (loop0): xfs_buf_find: daddr 0x7fb28 out of range, EOFS 0x8000 ..... BUG: unable to handle kernel NULL pointer dereference at 00000000000000c8 .... Call Trace: xfs_bmap_add_extent_hole_real+0x67d/0x930 xfs_bmapi_write+0x934/0xc90 xfs_da_grow_inode_int+0x27e/0x2f0 xfs_dir2_grow_inode+0x55/0x130 xfs_dir2_sf_to_block+0x94/0x5d0 xfs_dir2_sf_addname+0xd0/0x590 xfs_dir_createname+0x168/0x1a0 xfs_rename+0x658/0x9b0 By checking that free space records pulled from the trees are within the valid range, we catch many of these corruptions before they can do damage. This is a generic btree record checking deficiency. We need to validate the records we fetch from all the different btrees before we use them to catch corruptions like this. This patch results in a corrupt record emitting an error message and returning -EFSCORRUPTED, and the higher layers catch that and abort: XFS (loop0): Size Freespace BTree record corruption in AG 0 detected! XFS (loop0): start block 0x0 block count 0x0 XFS (loop0): Internal error xfs_trans_cancel at line 1012 of file fs/xfs/xfs_trans.c. Caller xfs_create+0x42a/0x670 ..... Call Trace: dump_stack+0x85/0xcb xfs_trans_cancel+0x19f/0x1c0 xfs_create+0x42a/0x670 xfs_generic_create+0x1f6/0x2c0 vfs_create+0xf9/0x180 do_mknodat+0x1f9/0x210 do_syscall_64+0x5a/0x180 entry_SYSCALL_64_after_hwframe+0x49/0xbe ..... XFS (loop0): xfs_do_force_shutdown(0x8) called from line 1013 of file fs/xfs/xfs_trans.c. Return address = ffffffff81500868 XFS (loop0): Corruption of in-memory data detected. Shutting down filesystem Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
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| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.