[PATCH 3.14 30/33] pstore: Fix NULL pointer fault if get NULL prz in ramoops_get_next_prz

Greg Kroah-Hartman
2015-02-03T23:22:10Z

From: Liu ShuoX <shuox.liu@intel.com>

commit b0aa931fb84431394d995472d0af2a6c2b61064d upstream.

ramoops_get_next_prz get the prz according the paramters. If it get a
uninitialized prz, access its members by following persistent_ram_old_size(prz)
will cause a NULL pointer crash.
Ex: if ftrace_size is 0, fprz will be NULL.

Fix it by return NULL in advance.

Signed-off-by: Liu ShuoX <shuox.liu@intel.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: HuKeping <hukeping@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/pstore/ram.c | 2 ++
1 file changed, 2 insertions(+)

--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -125,6 +125,8 @@ ramoops_get_next_prz(struct persistent_r
return NULL;

prz = przs[i];
+ if (!prz)
+ return NULL;

/* Update old/shadowed buffer. */
if (update)