From: Shyam Prasad N sprasad@microsoft.com
[ Upstream commit 33f736187d08f6bc822117629f263b97d3df4165 ]
In smb2_compound_op we have a possible use-after-free which can cause hard to debug problems later on.
This was revealed during stress testing with KASAN enabled kernel. Fixing it by moving the cfile free call to a few lines below, after the usage.
Fixes: 76894f3e2f71 ("cifs: improve symlink handling for smb2+") Reviewed-by: Paulo Alcantara (SUSE) pc@manguebit.com Signed-off-by: Shyam Prasad N sprasad@microsoft.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/cifs/smb2inode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/cifs/smb2inode.c b/fs/cifs/smb2inode.c index 163a03298430d..7e3ac4cb4efa6 100644 --- a/fs/cifs/smb2inode.c +++ b/fs/cifs/smb2inode.c @@ -398,9 +398,6 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon, rsp_iov);
finished: - if (cfile) - cifsFileInfo_put(cfile); - SMB2_open_free(&rqst[0]); if (rc == -EREMCHG) { pr_warn_once("server share %s deleted\n", tcon->tree_name); @@ -529,6 +526,9 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon, break; }
+ if (cfile) + cifsFileInfo_put(cfile); + if (rc && err_iov && err_buftype) { memcpy(err_iov, rsp_iov, 3 * sizeof(*err_iov)); memcpy(err_buftype, resp_buftype, 3 * sizeof(*err_buftype));