From: Shirish Pargaonkar shirishpargaonkar@gmail.com

Validate_buf () function checks for an expected minimum sized response passed to query_info() function. For security information, the size of a security descriptor can be smaller (one subauthority, no ACEs) than the size of the structure that defines FileInfoClass of FileAllInformation.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199725 Cc: stable@vger.kernel.org Signed-off-by: Shirish Pargaonkar shirishpargaonkar@gmail.com Signed-off-by: Noah Morrison noah.morrison@rubrik.com

--- fs/cifs/cifsacl.h | 14 ++++++++++++++ fs/cifs/smb2pdu.c | 3 +-- 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/cifsacl.h b/fs/cifs/cifsacl.h index 4f38848..dd95a6f 100644 --- a/fs/cifs/cifsacl.h +++ b/fs/cifs/cifsacl.h @@ -98,4 +98,18 @@ struct cifs_ace { struct cifs_sid sid; /* ie UUID of user or group who gets these perms */ } __attribute__((packed));

+/* + * Minimum security identifier can be one for system defined Users + * and Groups such as NULL SID and World or Built-in accounts such + * as Administrator and Guest and consists of + * Revision + Num (Sub)Auths + Authority + Domain (one Subauthority) + */ +#define MIN_SID_LEN (1 + 1 + 6 + 4) /* in bytes */ + +/* + * Minimum security descriptor can be one without any SACL and DACL and can + * consist of revision, type, and two sids of minimum size for owner and group + */ +#define MIN_SEC_DESC_LEN (sizeof(struct cifs_ntsd) + (2 * MIN_SID_LEN)) + #endif /* _CIFSACL_H */ diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 60db51b..47538a4 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -2374,8 +2374,7 @@ int SMB2_query_info(const unsigned int xid, struct cifs_tcon *tcon,

return query_info(xid, tcon, persistent_fid, volatile_fid, 0, SMB2_O_INFO_SECURITY, additional_info, - SMB2_MAX_BUFFER_SIZE, - sizeof(struct smb2_file_all_info), data, plen); + SMB2_MAX_BUFFER_SIZE, MIN_SEC_DESC_LEN, data, plen); }

int