From 6cf5abbfa8c8a2826d56e38ed1956a0e2f0c85b9 Mon Sep 17 00:00:00 2001 From: Ronnie Sahlberg Date: Wed, 16 Dec 2020 08:51:33 +1000 Subject: [PATCH] cifs: fix use after free in cifs_smb3_do_mount() Reported-by: Dan Carpenter Signed-off-by: Ronnie Sahlberg Signed-off-by: Steve French --- fs/cifs/cifsfs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 4c9e12b46810..ce0d0037fd0a 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -854,12 +854,14 @@ cifs_smb3_do_mount(struct file_system_type *fs_type, if (IS_ERR(sb)) { root = ERR_CAST(sb); cifs_umount(cifs_sb); + cifs_sb = NULL; goto out; } if (sb->s_root) { cifs_dbg(FYI, "Use existing superblock\n"); cifs_umount(cifs_sb); + cifs_sb = NULL; } else { rc = cifs_read_super(sb); if (rc) { @@ -870,7 +872,7 @@ cifs_smb3_do_mount(struct file_system_type *fs_type, sb->s_flags |= SB_ACTIVE; } - root = cifs_get_root(cifs_sb->ctx, sb); + root = cifs_get_root(cifs_sb ? cifs_sb->ctx : old_ctx, sb); if (IS_ERR(root)) goto out_super; -- 2.20.1