This is a port of Linux commit cdbb65c4c7ead680ebe54f4f0d486e2847a500ea:
| Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
| AuthorDate: Wed Aug 1 10:38:43 2018 -0700
|
| Anatoly continues to find issues with fuzzed squashfs images.
|
| This time, corrupt, missing, or undersized data for the page filling
| wasn't checked for, because the squashfs_{copy,read}_cache() functions
| did the squashfs_copy_data() call without checking the resulting data
| size.
|
| Which could result in the page cache pages being incompletely filled in,
| and no error indication to the user space reading garbage data.
|
| So make a helper function for the "fill in pages" case, because the
| exact same incomplete sequence existed in two places.
|
| [ I should have made a squashfs branch for these things, but I didn't
| intend to start doing them in the first place.
|
| My historical connection through cramfs is why I got into looking at
| these issues at all, and every time I (continue to) think it's a
| one-off.
|
| Because _this_ time is always the last time. Right? - Linus ]
|
| Reported-by: Anatoly Trosinenko <anatoly.trosinenko@xxxxxxxxx>
| Tested-by: Willy Tarreau <w@xxxxxx>
| Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
| Cc: Phillip Lougher <phillip@xxxxxxxxxxxxxxx>
| Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Reported-by: Richard Weinberger <richard@xxxxxxxxxxxxx>
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
fs/squashfs/file.c | 23 +++++++++++++++++++----
fs/squashfs/file_cache.c | 5 +++--
fs/squashfs/squashfs.h | 2 +-
3 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c
index 1413ef7ecbd8..8316f0edb645 100644
--- a/fs/squashfs/file.c
+++ b/fs/squashfs/file.c
@@ -347,12 +347,23 @@ static int read_blocklist(struct inode *inode, int index, u64 *block)
return squashfs_block_size(size);
}
+static int squashfs_fill_page(char *dest, struct squashfs_cache_entry *buffer,
+ int offset, int avail)
+{
+ int copied;
+
+ copied = squashfs_copy_data(dest, buffer, offset, avail);
+ memset(dest + avail, 0, PAGE_CACHE_SIZE - avail);
+
+ return copied == avail ? 0 : -EILSEQ;
+}
+
/* Copy data into page cache */
-void squashfs_copy_cache(struct page *page, struct squashfs_cache_entry *buffer,
+int squashfs_copy_cache(struct page *page, struct squashfs_cache_entry *buffer,
int bytes, int offset)
{
- int i;
struct squashfs_page *sq_page = squashfs_page(page);
+ int ret, i;
/*
* Loop copying datablock into pages. As the datablock likely covers
@@ -366,10 +377,14 @@ void squashfs_copy_cache(struct page *page, struct squashfs_cache_entry *buffer,
TRACE("bytes %d, i %d, available_bytes %d\n", bytes, i, avail);
- squashfs_copy_data(sq_page->buf[i], buffer, offset, avail);
- memset(sq_page->buf[i] + avail, 0, PAGE_CACHE_SIZE - avail);
+ ret = squashfs_fill_page(sq_page->buf[i], buffer, offset, avail);
+ if (ret)
+ return ret;
+
sq_page->idx++;
}
+
+ return 0;
}
/* Read datablock stored packed inside a fragment (tail-end packed block) */
diff --git a/fs/squashfs/file_cache.c b/fs/squashfs/file_cache.c
index 9443e4558d1a..fbd829849d18 100644
--- a/fs/squashfs/file_cache.c
+++ b/fs/squashfs/file_cache.c
@@ -24,11 +24,12 @@ int squashfs_readpage_block(struct page *page, u64 block, int bsize)
block, bsize);
int res = buffer->error;
+ if (!res)
+ res = squashfs_copy_cache(page, buffer, buffer->length, 0);
+
if (res)
ERROR("Unable to read page, block %llx, size %x\n", block,
bsize);
- else
- squashfs_copy_cache(page, buffer, buffer->length, 0);
squashfs_cache_put(buffer);
return res;
diff --git a/fs/squashfs/squashfs.h b/fs/squashfs/squashfs.h
index d22e83dc3c55..456021dcfd3e 100644
--- a/fs/squashfs/squashfs.h
+++ b/fs/squashfs/squashfs.h
@@ -93,7 +93,7 @@ extern int squashfs_frag_lookup(struct super_block *, unsigned int, u64 *);
extern __le64 *squashfs_read_fragment_index_table(struct super_block *,
u64, u64, unsigned int);
/* file.c */
-void squashfs_copy_cache(struct page *, struct squashfs_cache_entry *, int,
+int squashfs_copy_cache(struct page *, struct squashfs_cache_entry *, int,
int);
extern int squashfs_readpage(struct file *file, struct page *page);
--
2.39.2
