From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aleksa Sarai Subject: [PATCH v2] scsi: require CAP_SYS_ADMIN to write to procfs interface Date: Sun, 5 Nov 2017 07:26:24 +1100 Message-ID: <20171104202624.6605-1-asarai__1208.53054472736$1509827254$gmane$org@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: "James E.J. Bottomley" , "Martin K. Petersen" Cc: linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cyphar-gVpy/LI/lHzQT0dZR+AlfA@public.gmane.org, "Eric W. Biederman" List-Id: containers.vger.kernel.org Previously, the only capability effectively required to operate on the /proc/scsi interface was CAP_DAC_OVERRIDE (or for some other files, having an fsuid of GLOBAL_ROOT_UID was enough). This means that semi-privileged processes could interfere with core components of a system (such as causing a DoS by removing the underlying SCSI device of the host's / mount). Cc: Cc: "Eric W. Biederman" Signed-off-by: Aleksa Sarai --- drivers/scsi/scsi_proc.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/scsi_proc.c b/drivers/scsi/scsi_proc.c index 480a597b3877..8c891ab16b11 100644 --- a/drivers/scsi/scsi_proc.c +++ b/drivers/scsi/scsi_proc.c @@ -51,7 +51,10 @@ static ssize_t proc_scsi_host_write(struct file *file, const char __user *buf, struct Scsi_Host *shost = PDE_DATA(file_inode(file)); ssize_t ret = -ENOMEM; char *page; - + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (count > PROC_BLOCK_SIZE) return -EOVERFLOW; @@ -313,6 +316,9 @@ static ssize_t proc_scsi_write(struct file *file, const char __user *buf, char *buffer, *p; int err; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (!buf || length > PAGE_SIZE) return -EINVAL; -- 2.14.3