[PATCH] erofs: fix uninit-value in z_erofs_lz4_decompress

Edward Adam Davis
2023-12-29T11:14:44Z

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@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
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);

if (ret >= 0)
memset(out + ret, 0, rq->outputsize - ret);
--
2.43.0