From 2910c59fd0423f87aca3a669b156a2325da63745 Mon Sep 17 00:00:00 2001 From: Phillip Lougher Date: Thu, 23 Jul 2020 21:15:40 -0700 Subject: squashfs: fix length field overlap check in metadata reading This is a regression introduced by the "migrate from ll_rw_block usage to BIO" patch. Squashfs packs structures on byte boundaries, and due to that the length field (of the metadata block) may not be fully in the current block. The new code rewrote and introduced a faulty check for that edge case. Fixes: 93e72b3c612adcaca1 ("squashfs: migrate from ll_rw_block usage to BIO") Reported-by: Bernd Amend Signed-off-by: Phillip Lougher Signed-off-by: Andrew Morton Cc: Christoph Hellwig Cc: Adrien Schildknecht Cc: Guenter Roeck Cc: Daniel Rosenberg Link: http://lkml.kernel.org/r/20200717195536.16069-1-phillip@squashfs.org.uk Signed-off-by: Linus Torvalds --- fs/squashfs/block.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/squashfs/block.c') diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c index 64f61330564a..76bb1c846845 100644 --- a/fs/squashfs/block.c +++ b/fs/squashfs/block.c @@ -175,7 +175,7 @@ int squashfs_read_data(struct super_block *sb, u64 index, int length, /* Extract the length of the metadata block */ data = page_address(bvec->bv_page) + bvec->bv_offset; length = data[offset]; - if (offset <= bvec->bv_len - 1) { + if (offset < bvec->bv_len - 1) { length |= data[offset + 1] << 8; } else { if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all))) { -- cgit From f26044c83e6e473a61917f5db411d1417327d425 Mon Sep 17 00:00:00 2001 From: Phillip Lougher Date: Thu, 20 Aug 2020 17:42:21 -0700 Subject: squashfs: avoid bio_alloc() failure with 1Mbyte blocks This is a regression introduced by the patch "migrate from ll_rw_block usage to BIO". Bio_alloc() is limited to 256 pages (1 Mbyte). This can cause a failure when reading 1 Mbyte block filesystems. The problem is a datablock can be fully (or almost uncompressed), requiring 256 pages, but, because blocks are not aligned to page boundaries, it may require 257 pages to read. Bio_kmalloc() can handle 1024 pages, and so use this for the edge condition. Fixes: 93e72b3c612a ("squashfs: migrate from ll_rw_block usage to BIO") Reported-by: Nicolas Prochazka Reported-by: Tomoatsu Shimada Signed-off-by: Phillip Lougher Signed-off-by: Andrew Morton Reviewed-by: Guenter Roeck Cc: Philippe Liard Cc: Christoph Hellwig Cc: Adrien Schildknecht Cc: Daniel Rosenberg Cc: Link: http://lkml.kernel.org/r/20200815035637.15319-1-phillip@squashfs.org.uk Signed-off-by: Linus Torvalds --- fs/squashfs/block.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'fs/squashfs/block.c') diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c index 76bb1c846845..8a19773b5a0b 100644 --- a/fs/squashfs/block.c +++ b/fs/squashfs/block.c @@ -87,7 +87,11 @@ static int squashfs_bio_read(struct super_block *sb, u64 index, int length, int error, i; struct bio *bio; - bio = bio_alloc(GFP_NOIO, page_count); + if (page_count <= BIO_MAX_PAGES) + bio = bio_alloc(GFP_NOIO, page_count); + else + bio = bio_kmalloc(GFP_NOIO, page_count); + if (!bio) return -ENOMEM; -- cgit