From 893e5e9b7369a02e7ceaa6d98db6739162005b03 Mon Sep 17 00:00:00 2001 From: Gao Xiang Date: Mon, 4 Mar 2024 11:53:39 +0800 Subject: erofs: fix uninitialized page cache reported by KMSAN syzbot reports a KMSAN reproducer [1] which generates a crafted filesystem image and causes IMA to read uninitialized page cache. Later, (rq->outputsize > rq->inputsize) will be formally supported after either large uncompressed pclusters (> block size) or big lclusters are landed. However, currently there is no way to generate such filesystems by using mkfs.erofs. Thus, let's mark this condition as unsupported for now. [1] https://lore.kernel.org/r/0000000000002be12a0611ca7ff8@google.com Reported-and-tested-by: syzbot+7bc44a489f0ef0670bd5@syzkaller.appspotmail.com Fixes: 1ca01520148a ("erofs: refine z_erofs_transform_plain() for sub-page block support") Reviewed-by: Sandeep Dhavale Reviewed-by: Yue Hu Reviewed-by: Chao Yu Signed-off-by: Gao Xiang Link: https://lore.kernel.org/r/20240304035339.425857-1-hsiangkao@linux.alibaba.com --- fs/erofs/decompressor.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c index d4cee95af14c..2ec9b2bb628d 100644 --- a/fs/erofs/decompressor.c +++ b/fs/erofs/decompressor.c @@ -323,7 +323,8 @@ static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq, unsigned int cur = 0, ni = 0, no, pi, po, insz, cnt; u8 *kin; - DBG_BUGON(rq->outputsize > rq->inputsize); + if (rq->outputsize > rq->inputsize) + return -EOPNOTSUPP; if (rq->alg == Z_EROFS_COMPRESSION_INTERLACED) { cur = bs - (rq->pageofs_out & (bs - 1)); pi = (rq->pageofs_in + rq->inputsize - cur) & ~PAGE_MASK; -- cgit From 4127caee89612a84adedd78c9453089138cd5afe Mon Sep 17 00:00:00 2001 From: Gao Xiang Date: Wed, 6 Mar 2024 13:31:38 +0800 Subject: erofs: apply proper VMA alignment for memory mapped files on THP There are mainly two reasons that thp_get_unmapped_area() should be used for EROFS as other filesystems: - It's needed to enable PMD mappings as a FSDAX filesystem, see commit 74d2fad1334d ("thp, dax: add thp_get_unmapped_area for pmd mappings"); - It's useful together with large folios and CONFIG_READ_ONLY_THP_FOR_FS which enable THPs for mmapped files (e.g. shared libraries) even without FSDAX. See commit 1854bc6e2420 ("mm/readahead: Align file mappings for non-DAX"). Fixes: 06252e9ce05b ("erofs: dax support for non-tailpacking regular file") Fixes: ce529cc25b18 ("erofs: enable large folios for iomap mode") Fixes: e6687b89225e ("erofs: enable large folios for fscache mode") Reviewed-by: Jingbo Xu Reviewed-by: Chao Yu Signed-off-by: Gao Xiang Link: https://lore.kernel.org/r/20240306053138.2240206-1-hsiangkao@linux.alibaba.com --- fs/erofs/data.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/erofs/data.c b/fs/erofs/data.c index c98aeda8abb2..3d9721b3faa8 100644 --- a/fs/erofs/data.c +++ b/fs/erofs/data.c @@ -447,5 +447,6 @@ const struct file_operations erofs_file_fops = { .llseek = generic_file_llseek, .read_iter = erofs_file_read_iter, .mmap = erofs_file_mmap, + .get_unmapped_area = thp_get_unmapped_area, .splice_read = filemap_splice_read, }; -- cgit