erofs: fix inconsistent per-file compression format
commit 118a8cf5 upstream. EROFS can select compression algorithms on a per-file basis, and each per-file compression algorithm needs to be marked in the on-disk superblock for initialization. However, syzkaller can generate inconsistent crafted images that use an unsupported algorithmtype for specific inodes, e.g. use MicroLZMA algorithmtype even it's not set in `sbi->available_compr_algs`. This can lead to an unexpected "BUG: kernel NULL pointer dereference" if the corresponding decompressor isn't built-in. Fix this by checking against `sbi->available_compr_algs` for each m_algorithmformat request. Incorrect !erofs_sb_has_compr_cfgs preset bitmap is now fixed together since it was harmless previously. Reported-by: <bugreport@ubisectech.com> Fixes: 8f899262 ("erofs: get compression algorithms directly on mapping") Fixes: 622ceadd ("erofs: lzma compression support") Reviewed-by: Yue Hu <huyue2@coolpad.com> Link: https://lore.kernel.org/r/20240113150602.1471050-1-hsiangkao@linux.alibaba.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Signed-off-by: Yue Hu <huyue2@coolpad.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
parent
54407d9b
Please register or sign in to comment