speakup: Avoid crash on very long word

commit c8d2f34ea96ea3bce6ba2535f867f0d4ee3b22e1 upstream.

In case a console is set up really large and contains a really long word
(> 256 characters), we have to stop before the length of the word buffer.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Fixes: c6e3fd22cd538 ("Staging: add speakup to the staging directory")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240323164843.1426997-1-samuel.thibault@ens-lyon.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/speakup/main.c b/drivers/staging/speakup/main.c
index 11c3b47b8a22a06dfa70978c4071eabb3ce75a64..08b07e77bb9d1aa4ca0949ef53a42b7466cf3936 100644 (file)
--- a/drivers/staging/speakup/main.c
+++ b/drivers/staging/speakup/main.c
@@ -577,7 +577,7 @@ static u_long get_word(struct vc_data *vc)
        }
        attr_ch = get_char(vc, (u_short *)tmp_pos, &spk_attr);
        buf[cnt++] = attr_ch;
-       while (tmpx < vc->vc_cols - 1) {
+       while (tmpx < vc->vc_cols - 1 && cnt < sizeof(buf) - 1) {
                tmp_pos += 2;
                tmpx++;
                ch = get_char(vc, (u_short *)tmp_pos, &temp);