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Linux kernel source tree
[BUG]
A corrupted subvolume tree can leave an EXTENT_DATA item attached to an
inode whose mode is not S_IFREG or S_IFLNK. During send, such an item can
be treated as file data and crash through a NULL address_space operation:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
Call Trace:
<TASK>
read_pages+0x80b/0xb30 mm/readahead.c:173
page_cache_ra_unbounded+0x40d/0x890 mm/readahead.c:302
do_page_cache_ra mm/readahead.c:332 [inline]
page_cache_ra_order+0xa16/0xcd0 mm/readahead.c:535
page_cache_sync_ra+0x5ce/0x9d0 mm/readahead.c:626
page_cache_sync_readahead include/linux/pagemap.h:1379 [inline]
put_file_data fs/btrfs/send.c:5224 [inline]
send_write fs/btrfs/send.c:5291 [inline]
send_extent_data+0x16b2/0x29b0 fs/btrfs/send.c:5715
send_write_or_clone fs/btrfs/send.c:6135 [inline]
process_extent+0x5d4/0x17b0 fs/btrfs/send.c:6504
changed_extent fs/btrfs/send.c:7079 [inline]
changed_cb+0x22f9/0x3cd0 fs/btrfs/send.c:7245
full_send_tree fs/btrfs/send.c:7318 [inline]
send_subvol fs/btrfs/send.c:7910 [inline]
btrfs_ioctl_send+0x46a9/0x57f0 fs/btrfs/send.c:8248
...
[CAUSE]
process_extent() skips extent items for symlinks but assumes every other
inode with an extent item is a regular file. For a corrupted non-regular
inode, btrfs_iget() does not install the regular file address_space
operations. The readahead fallback can then call a NULL read_folio
callback before the existing validation in btrfs_get_extent() can run.
[FIX]
Reject extent items for inode types other than regular files and symlinks
at the common send extent-processing boundary. Symlink handling is left
unchanged because send emits symlink data from read_symlink(). This covers
full, incremental and new-generation sends without adding a check to the
regular I/O path.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: ZhengYuan Huang <gality369@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
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| virt | ||
| .clang-format | ||
| .clippy.toml | ||
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| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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