On 2023/12/29 19:09, Edward Adam Davis wrote:
When LZ4 decompression fails, the number of bytes read from out should be inputsize plus the returned overflow value ret. Reported-and-tested-by: syzbot+6c746eea496f34b3161d@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Edward Adam Davis <eadavis@xxxxxx> --- fs/erofs/decompressor.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c index 021be5feb1bc..8ac3f96676c4 100644 --- a/fs/erofs/decompressor.c +++ b/fs/erofs/decompressor.c @@ -250,7 +250,8 @@ static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx, print_hex_dump(KERN_DEBUG, "[ in]: ", DUMP_PREFIX_OFFSET, 16, 1, src + inputmargin, rq->inputsize, true); print_hex_dump(KERN_DEBUG, "[out]: ", DUMP_PREFIX_OFFSET, - 16, 1, out, rq->outputsize, true); + 16, 1, out, (ret < 0 && rq->inputsize > 0) ? + (ret + rq->inputsize) : rq->outputsize, true);
It's incorrect since output decompressed buffer has no relationship with `rq->inputsize` and `ret + rq->inputsize` is meaningless too. Also, the issue was already fixed by avoiding debugging messages as https://lore.kernel.org/r/20231227151903.2900413-1-hsiangkao@xxxxxxxxxxxxxxxxx Thanks, Gao Xiang
