pstore: Fix NULL pointer dereference in console writes

Passing a NULL id causes a NULL pointer deference in writers such as
erst_writer and efi_pstore_write because they expect to update this id.
Pass a dummy id instead.

This avoids a cascade of oopses caused when the initial
pstore_console_write passes a null which in turn causes writes to the
console causing further oopses in subsequent pstore_console_write calls.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index a40da07e93d68a88e670b5256a1c22c4badeb634..947fbe06c3b1f2ed0948b8fb050b43f2c48ff591 100644 (file)
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -161,6 +161,7 @@ static void pstore_console_write(struct console *con, const char *s, unsigned c)
 
        while (s < e) {
                unsigned long flags;
+               u64 id;
 
                if (c > psinfo->bufsize)
                        c = psinfo->bufsize;
@@ -172,7 +173,7 @@ static void pstore_console_write(struct console *con, const char *s, unsigned c)
                        spin_lock_irqsave(&psinfo->buf_lock, flags);
                }
                memcpy(psinfo->buf, s, c);
-               psinfo->write(PSTORE_TYPE_CONSOLE, 0, NULL, 0, c, psinfo);
+               psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, c, psinfo);
                spin_unlock_irqrestore(&psinfo->buf_lock, flags);
                s += c;
                c = e - s;