4.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx> commit ee25c6dd7b05113783ce1f4fab6b30fc00d29b8d upstream. 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@xxxxxxxxxxxxxxx> Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx> Reviewed-by: Noah Morrison <noah.morrison@xxxxxxxxxx> Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/cifs/cifsacl.h | 14 ++++++++++++++ fs/cifs/smb2pdu.c | 3 +-- 2 files changed, 15 insertions(+), 2 deletions(-) --- 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 */ --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -2378,8 +2378,7 @@ SMB2_query_acl(const unsigned int xid, s 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
