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

Colin King
2012-11-14T11:50:00Z

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>
---
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