linux-kernel - [PATCH v2] ksmbd: free ppace array on error in parse

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Message-ID: <20240109141445.6808-1-pchelkin@ispras.ru>
Date: Tue,  9 Jan 2024 17:14:44 +0300
From: Fedor Pchelkin <pchelkin@...ras.ru>
To: Namjae Jeon <linkinjeon@...nel.org>
Cc: Fedor Pchelkin <pchelkin@...ras.ru>,
	Steve French <sfrench@...ba.org>,
	Sergey Senozhatsky <senozhatsky@...omium.org>,
	Tom Talpey <tom@...pey.com>,
	Hyunchul Lee <hyc.lee@...il.com>,
	linux-cifs@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Alexey Khoroshilov <khoroshilov@...ras.ru>,
	lvc-project@...uxtesting.org
Subject: [PATCH v2] ksmbd: free ppace array on error in parse_dacl

The ppace array is not freed if one of the init_acl_state() calls inside
parse_dacl() fails. At the moment the function may fail only due to the
memory allocation errors so it's highly unlikely in this case but
nevertheless a fix is needed.

Move ppace allocation after the init_acl_state() calls with proper error
handling.

Found by Linux Verification Center (linuxtesting.org).

Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Signed-off-by: Fedor Pchelkin <pchelkin@...ras.ru>
---
v2: refine the patch with moving ppace allocation into another place per
    Namjae's suggestion; update the commit description accordingly.

 fs/smb/server/smbacl.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/fs/smb/server/smbacl.c b/fs/smb/server/smbacl.c
index 1164365533f0..1c9775f1efa5 100644
--- a/fs/smb/server/smbacl.c
+++ b/fs/smb/server/smbacl.c
@@ -401,10 +401,6 @@ static void parse_dacl(struct mnt_idmap *idmap,
 	if (num_aces > ULONG_MAX / sizeof(struct smb_ace *))
 		return;
 
-	ppace = kmalloc_array(num_aces, sizeof(struct smb_ace *), GFP_KERNEL);
-	if (!ppace)
-		return;
-
 	ret = init_acl_state(&acl_state, num_aces);
 	if (ret)
 		return;
@@ -414,6 +410,13 @@ static void parse_dacl(struct mnt_idmap *idmap,
 		return;
 	}
 
+	ppace = kmalloc_array(num_aces, sizeof(struct smb_ace *), GFP_KERNEL);
+	if (!ppace) {
+		free_acl_state(&default_acl_state);
+		free_acl_state(&acl_state);
+		return;
+	}
+
 	/*
 	 * reset rwx permissions for user/group/other.
 	 * Also, if num_aces is 0 i.e. DACL has no ACEs,
-- 
2.43.0