From: Clemens Ladisch <clemens@ladisch.de>
Date: Sat, 18 Mar 2017 22:10:33 +0000 (+0100)
Subject: rawmidi: virtual: fix reading into a small buffer
X-Git-Tag: v1.1.4~20
X-Git-Url: https://git.alsa-project.org/?a=commitdiff_plain;h=d71f294566e53c967a6a1e2d5c684499ec390d69;p=alsa-lib.git

rawmidi: virtual: fix reading into a small buffer

In the special case for handling partial messages, the pointer
calculations were wrong, which would result in data corruption.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Reviewd-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---

diff --git a/src/rawmidi/rawmidi_virt.c b/src/rawmidi/rawmidi_virt.c
index e5b17e48..7daf3e16 100644
--- a/src/rawmidi/rawmidi_virt.c
+++ b/src/rawmidi/rawmidi_virt.c
@@ -263,8 +263,8 @@ static ssize_t snd_rawmidi_virtual_read(snd_rawmidi_t *rmidi, void *buffer, size
 		}
 		size1 = virt->in_buf_size - virt->in_buf_ofs;
 		if ((size_t)size1 > size) {
-			virt->in_buf_ofs += size1 - size;
-			memcpy(buffer, virt->in_buf_ptr, size);
+			memcpy(buffer, virt->in_buf_ptr + virt->in_buf_ofs, size);
+			virt->in_buf_ofs += size;
 			result += size;
 			break;
 		}