Re: [syzbot] [PATCH] Test oob in squashfs readahead

[syzbot <syzbot+604424eb051c2f696163@syzkaller.appspotmail.com>]

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Subject: [PATCH] Test oob in squashfs readahead
Author: eadavis@qq.com

please test squashfs readahead oob

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 13d88ac54ddd

diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 581ce9519339..7db8f2920c9e 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -287,6 +287,7 @@ int squashfs_read_data(struct super_block *sb, u64 index, int length,
 
 		if (index + 2 > msblk->bytes_used) {
 			res = -EIO;
+			printk("srd1: i:%d, bu:%d \n", index, msblk->bytes_used);
 			goto out;
 		}
 		res = squashfs_bio_read(sb, index, 2, &bio, &offset);
@@ -295,6 +296,7 @@ int squashfs_read_data(struct super_block *sb, u64 index, int length,
 
 		if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all))) {
 			res = -EIO;
+			printk("srd2 \n");
 			goto out_free_bio;
 		}
 		/* Extract the length of the metadata block */
@@ -305,6 +307,7 @@ int squashfs_read_data(struct super_block *sb, u64 index, int length,
 		} else {
 			if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all))) {
 				res = -EIO;
+				printk("srd3 \n");
 				goto out_free_bio;
 			}
 			data = bvec_virt(bvec);
@@ -324,6 +327,7 @@ int squashfs_read_data(struct super_block *sb, u64 index, int length,
 	if (length < 0 || length > output->length ||
 			(index + length) > msblk->bytes_used) {
 		res = -EIO;
+		printk("srd4: l:%d, ol: %d, bu: %d \n", length, output->length, msblk->bytes_used);
 		goto out;
 	}
 
@@ -336,10 +340,12 @@ int squashfs_read_data(struct super_block *sb, u64 index, int length,
 
 	if (compressed) {
 		if (!msblk->stream) {
+			printk("srd5 \n");
 			res = -EIO;
 			goto out_free_bio;
 		}
 		res = msblk->thread_ops->decompress(msblk, bio, offset, length, output);
+		printk("srd6: r: %d \n", res);
 	} else {
 		res = copy_bio_to_actor(bio, output, offset, length);
 	}
diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c
index 8ba8c4c50770..b54d6b993357 100644
--- a/fs/squashfs/file.c
+++ b/fs/squashfs/file.c
@@ -461,6 +461,12 @@ static int squashfs_read_folio(struct file *file, struct folio *folio)
 	TRACE("Entered squashfs_readpage, page index %lx, start block %llx\n",
 				page->index, squashfs_i(inode)->start);
 
+	if (!file_end) {
+		printk("i:%p, is:%d, %s\n", inode, i_size_read(inode), __func__);
+		res = -EINVAL;
+		goto out;
+	}
+
 	if (page->index >= ((i_size_read(inode) + PAGE_SIZE - 1) >>
 					PAGE_SHIFT))
 		goto out;
@@ -547,6 +553,11 @@ static void squashfs_readahead(struct readahead_control *ractl)
 	int i, file_end = i_size_read(inode) >> msblk->block_log;
 	unsigned int max_pages = 1UL << shift;
 
+	if (!file_end && !start) {
+		printk("i:%p, is:%d, %s\n", inode, i_size_read(inode), __func__);
+		return;
+	}
+
 	readahead_expand(ractl, start, (len | mask) + 1);
 
 	pages = kmalloc_array(max_pages, sizeof(void *), GFP_KERNEL);
diff --git a/fs/squashfs/inode.c b/fs/squashfs/inode.c
index aa3411354e66..e7c2ccd6a382 100644
--- a/fs/squashfs/inode.c
+++ b/fs/squashfs/inode.c
@@ -403,9 +403,11 @@ int squashfs_read_inode(struct inode *inode, long long ino)
 	} else
 		squashfs_i(inode)->xattr_count = 0;
 
+	printk("in: %p, fs: %d, it: %d, %s\n", inode, inode->i_size, type, __func__);
 	return 0;
 
 failed_read:
+	printk("in: %p, fs: %d, it: %d, %s\n", inode, inode->i_size, type, __func__);
 	ERROR("Unable to read inode 0x%llx\n", ino);
 	return err;
 }