From 6f46c8c5d091ed4be38f46ae7931b06dbf301735 Mon Sep 17 00:00:00 2001 From: Norbert Manthey Date: Fri, 5 Jul 2019 15:06:00 +0200 Subject: [PATCH] pstore: Fix double-free in pstore_mkfile() failure path commit 4c6d80e1144bdf48cae6b602ae30d41f3e5c76a9 upstream. The pstore_mkfile() function is passed a pointer to a struct pstore_record. On success it consumes this 'record' pointer and references it from the created inode. On failure, however, it may or may not free the record. There are even two different code paths which return -ENOMEM -- one of which does and the other doesn't free the record. Make the behaviour deterministic by never consuming and freeing the record when returning failure, allowing the caller to do the cleanup consistently. Signed-off-by: Norbert Manthey Link: https://lore.kernel.org/r/1562331960-26198-1-git-send-email-nmanthey@amazon.de Fixes: 83f70f0769ddd ("pstore: Do not duplicate record metadata") Fixes: 1dfff7dd67d1a ("pstore: Pass record contents instead of copying") Cc: stable@vger.kernel.org [kees: also move "private" allocation location, rename inode cleanup label] Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman --- fs/pstore/inode.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c index 89a80b568a179..7fbe8f0582205 100644 --- a/fs/pstore/inode.c +++ b/fs/pstore/inode.c @@ -318,22 +318,21 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record) goto fail; inode->i_mode = S_IFREG | 0444; inode->i_fop = &pstore_file_operations; - private = kzalloc(sizeof(*private), GFP_KERNEL); - if (!private) - goto fail_alloc; - private->record = record; - scnprintf(name, sizeof(name), "%s-%s-%llu%s", pstore_type_to_name(record->type), record->psi->name, record->id, record->compressed ? ".enc.z" : ""); + private = kzalloc(sizeof(*private), GFP_KERNEL); + if (!private) + goto fail_inode; + dentry = d_alloc_name(root, name); if (!dentry) goto fail_private; + private->record = record; inode->i_size = private->total_size = size; - inode->i_private = private; if (record->time.tv_sec) @@ -349,7 +348,7 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record) fail_private: free_pstore_private(private); -fail_alloc: +fail_inode: iput(inode); fail: