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>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index a40da07e93d6..947fbe06c3b1 100644
--- 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;