Re: [PATCH RESEND] pstore: fix NULL pointer dereference in console writes

Anton Vorontsov
2012-11-15T02:53:14Z

On Wed, Nov 14, 2012 at 11:49:53AM +0000, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> 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>
> ---

Ugh. Thanks for the reminder, I completely forgot that I had this bit for
v3.7.

Applied, thanks! (I also added Cc: stable.)

> fs/pstore/platform.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
> index a40da07..947fbe0 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;
> --
> 1.7.10.4