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authorShyam Prasad N <sprasad@microsoft.com>2023-06-22 18:16:03 +0000
committerSteve French <stfrench@microsoft.com>2023-06-28 11:46:32 -0500
commit33f736187d08f6bc822117629f263b97d3df4165 (patch)
tree59ae7a75edb9e1ff59afcf294bf7825003d04d02 /fs/smb
parentf0b6a834a8f0d267a112b150827bb65d4fdc471c (diff)
cifs: prevent use-after-free by freeing the cfile later
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>
Diffstat (limited to 'fs/smb')
-rw-r--r--fs/smb/client/smb2inode.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c
index 163a03298430..7e3ac4cb4efa 100644
--- a/fs/smb/client/smb2inode.c
+++ b/fs/smb/client/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));