From: Yangxi Xiang xyangxi5@gmail.com
stable inclusion from stable-v5.10.132 commit bfee93c9a6c395f9aa62268f1cedf64999844926 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5YS3T
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 39cdb68c64d84e71a4a717000b6e5de208ee60cc upstream.
A memory overlapping copy occurs when deleting a long line. This memory overlapping copy can cause data corruption when scr_memcpyw is optimized to memcpy because memcpy does not ensure its behavior if the destination buffer overlaps with the source buffer. The line buffer is not always broken, because the memcpy utilizes the hardware acceleration, whose result is not deterministic.
Fix this problem by using replacing the scr_memcpyw with scr_memmovew.
Fixes: 81732c3b2fed ("tty vt: Fix line garbage in virtual console on command line edition") Cc: stable stable@kernel.org Signed-off-by: Yangxi Xiang xyangxi5@gmail.com Link: https://lore.kernel.org/r/20220628093322.5688-1-xyangxi5@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- drivers/tty/vt/vt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index 30fc2a60c352..2ebe73b116dc 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -855,7 +855,7 @@ static void delete_char(struct vc_data *vc, unsigned int nr) unsigned short *p = (unsigned short *) vc->vc_pos;
vc_uniscr_delete(vc, nr); - scr_memcpyw(p, p + nr, (vc->vc_cols - vc->state.x - nr) * 2); + scr_memmovew(p, p + nr, (vc->vc_cols - vc->state.x - nr) * 2); scr_memsetw(p + vc->vc_cols - vc->state.x - nr, vc->vc_video_erase_char, nr * 2); vc->vc_need_wrap = 0;