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Sheng YongandGreg Kroah-Hartman
65115472f7
[ Upstream commit9748f2f54f] For multiple devices, both primary and extra devices should be the same type. `erofs_init_device` has already guaranteed that if the primary is a file-backed device, extra devices should also be regular files. However, if the primary is a block device while the extra device is a file-backed device, `erofs_init_device` will get an ENOTBLK, which is not treated as an error in `erofs_fc_get_tree`, and that leads to an UAF: erofs_fc_get_tree get_tree_bdev_flags(erofs_fc_fill_super) erofs_read_superblock erofs_init_device // sbi->dif0 is not inited yet, // return -ENOTBLK deactivate_locked_super free(sbi) if (err is -ENOTBLK) sbi->dif0.file = filp_open() // sbi UAF So if -ENOTBLK is hitted in `erofs_init_device`, it means the primary device must be a block device, and the extra device is not a block device. The error can be converted to -EINVAL. Fixes:fb17675026("erofs: add file-backed mount support") Signed-off-by: Sheng Yong <shengyong1@xiaomi.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: Hongbo Li <lihongbo22@huawei.com> Link: https://lore.kernel.org/r/20250515014837.3315886-1-shengyong1@xiaomi.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Signed-off-by: Sasha Levin <sashal@kernel.org>