From 8665569e97dd52920713b95675409648986b5b0d Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Mon, 3 Dec 2018 16:39:01 -0800
Subject: [PATCH] pstore/ram: Avoid NULL deref in ftrace merging failure path
Git-commit: 8665569e97dd52920713b95675409648986b5b0d
Patch-mainline: v5.0-rc1
References: bsc#1051510
Given corruption in the ftrace records, it might be possible to allocate
tmp_prz without assigning prz to it, but still marking it as needing to
be freed, which would cause at least a NULL dereference.
smatch warnings:
fs/pstore/ram.c:340 ramoops_pstore_read() error: we previously assumed 'prz' could be null (see line 255)
https://lists.01.org/pipermail/kbuild-all/2018-December/055528.html
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 2fbea82bbb89 ("pstore: Merge per-CPU ftrace records into one")
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
fs/pstore/ram.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index e6d9560ea455..96f7d32cd184 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -291,6 +291,7 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record)
GFP_KERNEL);
if (!tmp_prz)
return -ENOMEM;
+ prz = tmp_prz;
free_prz = true;
while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
@@ -309,7 +310,6 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record)
goto out;
}
record->id = 0;
- prz = tmp_prz;
}
}
--
2.16.4