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authorPhillip Lougher <phillip@squashfs.org.uk>2020-07-24 07:15:40 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-07-24 22:42:41 +0300
commit2910c59fd0423f87aca3a669b156a2325da63745 (patch)
treef0dff9d23a9fc8507dff4b431c01dd77a5cff6c5
parente57942c5630f86880f2cefa61f4a1ab10d4864af (diff)
downloadlinux-sunxi-2910c59fd0423f87aca3a669b156a2325da63745.tar.xz
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 <bernd.amend@gmail.com> Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Adrien Schildknecht <adrien+dev@schischi.me> Cc: Guenter Roeck <groeck@chromium.org> Cc: Daniel Rosenberg <drosen@google.com> Link: http://lkml.kernel.org/r/20200717195536.16069-1-phillip@squashfs.org.uk Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/squashfs/block.c2
1 files changed, 1 insertions, 1 deletions
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))) {