[PATCH 5.4 090/215] vt: fix unicode buffer corruption when deleting characters

Greg Kroah-Hartman
2024-04-11T10:18:26Z

From: Nicolas Pitre <nico@fluxnic.net>

commit 1581dafaf0d34bc9c428a794a22110d7046d186d upstream.

This is the same issue that was fixed for the VGA text buffer in commit
39cdb68c64d8 ("vt: fix memory overlapping when deleting chars in the
buffer"). The cure is also the same i.e. replace memcpy() with memmove()
due to the overlaping buffers.

Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Fixes: 81732c3b2fed ("tty vt: Fix line garbage in virtual console on command line edition")
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/sn184on2-3p0q-0qrq-0218-895349s4753o@syhkavp.arg
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/tty/vt/vt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -405,7 +405,7 @@ static void vc_uniscr_delete(struct vc_d
char32_t *ln = uniscr->lines[vc->vc_y];
unsigned int x = vc->vc_x, cols = vc->vc_cols;

- memcpy(&ln[x], &ln[x + nr], (cols - x - nr) * sizeof(*ln));
+ memmove(&ln[x], &ln[x + nr], (cols - x - nr) * sizeof(*ln));
memset32(&ln[cols - nr], ' ', nr);
}
}