5.4-stable review patch. If anyone has any objections, please let me know.
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From: Gao Xiang hsiangkao@linux.alibaba.com
commit 1dd73601a1cba37a0ed5f89a8662c90191df5873 upstream.
As syzbot reported [1], the root cause is that i_size field is a signed type, and negative i_size is also less than EROFS_BLKSIZ. As a consequence, it's handled as fast symlink unexpectedly.
Let's fall back to the generic path to deal with such unusual i_size.
[1] https://lore.kernel.org/r/000000000000ac8efa05e7feaa1f@google.com
Reported-by: syzbot+f966c13b1b4fc0403b19@syzkaller.appspotmail.com Fixes: 431339ba9042 ("staging: erofs: add inode operations") Reviewed-by: Yue Hu huyue2@coolpad.com Link: https://lore.kernel.org/r/20220909023948.28925-1-hsiangkao@linux.alibaba.com Signed-off-by: Gao Xiang hsiangkao@linux.alibaba.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/erofs/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c index 0dbeaf68e1d6..ba981076d6f2 100644 --- a/fs/erofs/inode.c +++ b/fs/erofs/inode.c @@ -202,7 +202,7 @@ static int erofs_fill_symlink(struct inode *inode, void *data,
/* if it cannot be handled with fast symlink scheme */ if (vi->datalayout != EROFS_INODE_FLAT_INLINE || - inode->i_size >= PAGE_SIZE) { + inode->i_size >= PAGE_SIZE || inode->i_size < 0) { inode->i_op = &erofs_symlink_iops; return 0; }