From: Kees Cook <keescook@xxxxxxxxxxxx> [ Upstream commit 8665569e97dd52920713b95675409648986b5b0d ] 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@xxxxxxxxxx> Fixes: 2fbea82bbb89 ("pstore: Merge per-CPU ftrace records into one") Cc: "Joel Fernandes (Google)" <joel@xxxxxxxxxxxxxxxxx> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 015d74ee31a03..631ae057ab537 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -301,6 +301,7 @@ 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) { @@ -323,7 +324,6 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record) goto out; } record->id = 0; - prz = tmp_prz; } } -- 2.20.1
