nvme: fine-granular CAP_SYS_ADMIN for nvme io commands
Currently both io and admin commands are kept under a coarse-granular CAP_SYS_ADMIN check, disregarding file mode completely. $ ls -l /dev/ng* crw-rw-rw- 1 root root 242, 0 Sep 9 19:20 /dev/ng0n1 crw------- 1 root root 242, 1 Sep 9 19:20 /dev/ng0n2 In the example above, ng0n1 appears as if it may allow unprivileged read/write operation but it does not and behaves same as ng0n2. This patch implements a shift from CAP_SYS_ADMIN to more fine-granular control for io-commands. If CAP_SYS_ADMIN is present, nothing else is checked as before. Otherwise, following rules are in place - any admin-cmd is not allowed - vendor-specific and fabric commmand are not allowed - io-commands that can write are allowed if matching FMODE_WRITE permission is present - io-commands that read are allowed Add a helper nvme_cmd_allowed that implements above policy. Change all the callers of CAP_SYS_ADMIN to go through nvme_cmd_allowed for any decision making. Since file open mode is counted for any approval/denial, change at various places to keep file-mode information handy. Signed-off-by: Kanchan Joshi <joshi.k@samsung.com> Reviewed-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Kanchan Joshi
Christoph Hellwig
parent
cf3d008401
commit
855b7717f4
@ -8,6 +8,34 @@
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#include <linux/io_uring.h>
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#include "nvme.h"
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static bool nvme_cmd_allowed(struct nvme_ns *ns, struct nvme_command *c,
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fmode_t mode)
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{
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if (capable(CAP_SYS_ADMIN))
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return true;
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/*
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* Do not allow unprivileged processes to send vendor specific or fabrics
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* commands as we can't be sure about their effects.
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*/
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if (c->common.opcode >= nvme_cmd_vendor_start ||
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c->common.opcode == nvme_fabrics_command)
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return false;
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/* do not allow unprivileged admin commands */
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if (!ns)
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return false;
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/*
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* Only allow I/O commands that transfer data to the controller if the
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* special file is open for writing, but always allow I/O commands that
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* transfer data from the controller.
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*/
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if (nvme_is_write(c))
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return mode & FMODE_WRITE;
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return true;
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}
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/*
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* Convert integer values from ioctl structures to user pointers, silently
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* ignoring the upper bits in the compat case to match behaviour of 32-bit
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@ -261,7 +289,7 @@ static bool nvme_validate_passthru_nsid(struct nvme_ctrl *ctrl,
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}
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static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
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struct nvme_passthru_cmd __user *ucmd)
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struct nvme_passthru_cmd __user *ucmd, fmode_t mode)
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{
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struct nvme_passthru_cmd cmd;
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struct nvme_command c;
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@ -269,8 +297,6 @@ static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
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u64 result;
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int status;
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if (!capable(CAP_SYS_ADMIN))
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return -EACCES;
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if (copy_from_user(&cmd, ucmd, sizeof(cmd)))
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return -EFAULT;
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if (cmd.flags)
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@ -291,6 +317,9 @@ static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
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c.common.cdw14 = cpu_to_le32(cmd.cdw14);
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c.common.cdw15 = cpu_to_le32(cmd.cdw15);
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if (!nvme_cmd_allowed(ns, &c, mode))
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return -EACCES;
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if (cmd.timeout_ms)
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timeout = msecs_to_jiffies(cmd.timeout_ms);
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@ -308,15 +337,14 @@ static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
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}
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static int nvme_user_cmd64(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
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struct nvme_passthru_cmd64 __user *ucmd, bool vec)
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struct nvme_passthru_cmd64 __user *ucmd, bool vec,
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fmode_t mode)
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{
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struct nvme_passthru_cmd64 cmd;
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struct nvme_command c;
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unsigned timeout = 0;
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int status;
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if (!capable(CAP_SYS_ADMIN))
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return -EACCES;
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if (copy_from_user(&cmd, ucmd, sizeof(cmd)))
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return -EFAULT;
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if (cmd.flags)
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@ -337,6 +365,9 @@ static int nvme_user_cmd64(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
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c.common.cdw14 = cpu_to_le32(cmd.cdw14);
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c.common.cdw15 = cpu_to_le32(cmd.cdw15);
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if (!nvme_cmd_allowed(ns, &c, mode))
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return -EACCES;
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if (cmd.timeout_ms)
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timeout = msecs_to_jiffies(cmd.timeout_ms);
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@ -483,9 +514,6 @@ static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
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void *meta = NULL;
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int ret;
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if (!capable(CAP_SYS_ADMIN))
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return -EACCES;
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c.common.opcode = READ_ONCE(cmd->opcode);
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c.common.flags = READ_ONCE(cmd->flags);
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if (c.common.flags)
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@ -507,6 +535,9 @@ static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
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c.common.cdw14 = cpu_to_le32(READ_ONCE(cmd->cdw14));
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c.common.cdw15 = cpu_to_le32(READ_ONCE(cmd->cdw15));
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if (!nvme_cmd_allowed(ns, &c, ioucmd->file->f_mode))
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return -EACCES;
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d.metadata = READ_ONCE(cmd->metadata);
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d.addr = READ_ONCE(cmd->addr);
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d.data_len = READ_ONCE(cmd->data_len);
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@ -570,13 +601,13 @@ static bool is_ctrl_ioctl(unsigned int cmd)
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}
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static int nvme_ctrl_ioctl(struct nvme_ctrl *ctrl, unsigned int cmd,
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void __user *argp)
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void __user *argp, fmode_t mode)
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{
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switch (cmd) {
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case NVME_IOCTL_ADMIN_CMD:
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return nvme_user_cmd(ctrl, NULL, argp);
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return nvme_user_cmd(ctrl, NULL, argp, mode);
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case NVME_IOCTL_ADMIN64_CMD:
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return nvme_user_cmd64(ctrl, NULL, argp, false);
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return nvme_user_cmd64(ctrl, NULL, argp, false, mode);
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default:
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return sed_ioctl(ctrl->opal_dev, cmd, argp);
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}
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@ -601,14 +632,14 @@ struct nvme_user_io32 {
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#endif /* COMPAT_FOR_U64_ALIGNMENT */
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static int nvme_ns_ioctl(struct nvme_ns *ns, unsigned int cmd,
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void __user *argp)
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void __user *argp, fmode_t mode)
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{
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switch (cmd) {
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case NVME_IOCTL_ID:
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force_successful_syscall_return();
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return ns->head->ns_id;
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case NVME_IOCTL_IO_CMD:
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return nvme_user_cmd(ns->ctrl, ns, argp);
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return nvme_user_cmd(ns->ctrl, ns, argp, mode);
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/*
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* struct nvme_user_io can have different padding on some 32-bit ABIs.
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* Just accept the compat version as all fields that are used are the
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@ -620,19 +651,20 @@ static int nvme_ns_ioctl(struct nvme_ns *ns, unsigned int cmd,
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case NVME_IOCTL_SUBMIT_IO:
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return nvme_submit_io(ns, argp);
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case NVME_IOCTL_IO64_CMD:
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return nvme_user_cmd64(ns->ctrl, ns, argp, false);
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return nvme_user_cmd64(ns->ctrl, ns, argp, false, mode);
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case NVME_IOCTL_IO64_CMD_VEC:
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return nvme_user_cmd64(ns->ctrl, ns, argp, true);
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return nvme_user_cmd64(ns->ctrl, ns, argp, true, mode);
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default:
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return -ENOTTY;
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}
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}
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static int __nvme_ioctl(struct nvme_ns *ns, unsigned int cmd, void __user *arg)
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static int __nvme_ioctl(struct nvme_ns *ns, unsigned int cmd, void __user *arg,
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fmode_t mode)
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{
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if (is_ctrl_ioctl(cmd))
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return nvme_ctrl_ioctl(ns->ctrl, cmd, arg);
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return nvme_ns_ioctl(ns, cmd, arg);
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if (is_ctrl_ioctl(cmd))
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return nvme_ctrl_ioctl(ns->ctrl, cmd, arg, mode);
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return nvme_ns_ioctl(ns, cmd, arg, mode);
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}
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int nvme_ioctl(struct block_device *bdev, fmode_t mode,
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@ -640,7 +672,7 @@ int nvme_ioctl(struct block_device *bdev, fmode_t mode,
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{
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struct nvme_ns *ns = bdev->bd_disk->private_data;
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return __nvme_ioctl(ns, cmd, (void __user *)arg);
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return __nvme_ioctl(ns, cmd, (void __user *)arg, mode);
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}
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long nvme_ns_chr_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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@ -648,7 +680,7 @@ long nvme_ns_chr_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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struct nvme_ns *ns =
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container_of(file_inode(file)->i_cdev, struct nvme_ns, cdev);
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return __nvme_ioctl(ns, cmd, (void __user *)arg);
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return __nvme_ioctl(ns, cmd, (void __user *)arg, file->f_mode);
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}
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static int nvme_uring_cmd_checks(unsigned int issue_flags)
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@ -716,7 +748,8 @@ int nvme_ns_chr_uring_cmd_iopoll(struct io_uring_cmd *ioucmd,
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}
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#ifdef CONFIG_NVME_MULTIPATH
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static int nvme_ns_head_ctrl_ioctl(struct nvme_ns *ns, unsigned int cmd,
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void __user *argp, struct nvme_ns_head *head, int srcu_idx)
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void __user *argp, struct nvme_ns_head *head, int srcu_idx,
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fmode_t mode)
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__releases(&head->srcu)
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{
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struct nvme_ctrl *ctrl = ns->ctrl;
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@ -724,7 +757,7 @@ static int nvme_ns_head_ctrl_ioctl(struct nvme_ns *ns, unsigned int cmd,
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nvme_get_ctrl(ns->ctrl);
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srcu_read_unlock(&head->srcu, srcu_idx);
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ret = nvme_ctrl_ioctl(ns->ctrl, cmd, argp);
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ret = nvme_ctrl_ioctl(ns->ctrl, cmd, argp, mode);
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nvme_put_ctrl(ctrl);
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return ret;
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@ -749,9 +782,10 @@ int nvme_ns_head_ioctl(struct block_device *bdev, fmode_t mode,
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* deadlock when deleting namespaces using the passthrough interface.
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*/
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if (is_ctrl_ioctl(cmd))
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return nvme_ns_head_ctrl_ioctl(ns, cmd, argp, head, srcu_idx);
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return nvme_ns_head_ctrl_ioctl(ns, cmd, argp, head, srcu_idx,
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mode);
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ret = nvme_ns_ioctl(ns, cmd, argp);
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ret = nvme_ns_ioctl(ns, cmd, argp, mode);
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out_unlock:
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srcu_read_unlock(&head->srcu, srcu_idx);
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return ret;
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@ -773,9 +807,10 @@ long nvme_ns_head_chr_ioctl(struct file *file, unsigned int cmd,
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goto out_unlock;
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if (is_ctrl_ioctl(cmd))
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return nvme_ns_head_ctrl_ioctl(ns, cmd, argp, head, srcu_idx);
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return nvme_ns_head_ctrl_ioctl(ns, cmd, argp, head, srcu_idx,
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file->f_mode);
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ret = nvme_ns_ioctl(ns, cmd, argp);
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ret = nvme_ns_ioctl(ns, cmd, argp, file->f_mode);
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out_unlock:
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srcu_read_unlock(&head->srcu, srcu_idx);
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return ret;
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@ -849,7 +884,8 @@ int nvme_dev_uring_cmd(struct io_uring_cmd *ioucmd, unsigned int issue_flags)
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return ret;
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}
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static int nvme_dev_user_cmd(struct nvme_ctrl *ctrl, void __user *argp)
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static int nvme_dev_user_cmd(struct nvme_ctrl *ctrl, void __user *argp,
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fmode_t mode)
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{
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struct nvme_ns *ns;
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int ret;
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@ -873,7 +909,7 @@ static int nvme_dev_user_cmd(struct nvme_ctrl *ctrl, void __user *argp)
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kref_get(&ns->kref);
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up_read(&ctrl->namespaces_rwsem);
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ret = nvme_user_cmd(ctrl, ns, argp);
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ret = nvme_user_cmd(ctrl, ns, argp, mode);
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nvme_put_ns(ns);
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return ret;
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@ -890,11 +926,11 @@ long nvme_dev_ioctl(struct file *file, unsigned int cmd,
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switch (cmd) {
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case NVME_IOCTL_ADMIN_CMD:
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return nvme_user_cmd(ctrl, NULL, argp);
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return nvme_user_cmd(ctrl, NULL, argp, file->f_mode);
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case NVME_IOCTL_ADMIN64_CMD:
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return nvme_user_cmd64(ctrl, NULL, argp, false);
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return nvme_user_cmd64(ctrl, NULL, argp, false, file->f_mode);
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case NVME_IOCTL_IO_CMD:
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return nvme_dev_user_cmd(ctrl, argp);
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return nvme_dev_user_cmd(ctrl, argp, file->f_mode);
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case NVME_IOCTL_RESET:
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if (!capable(CAP_SYS_ADMIN))
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return -EACCES;
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@ -797,6 +797,7 @@ enum nvme_opcode {
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nvme_cmd_zone_mgmt_send = 0x79,
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nvme_cmd_zone_mgmt_recv = 0x7a,
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nvme_cmd_zone_append = 0x7d,
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nvme_cmd_vendor_start = 0x80,
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};
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#define nvme_opcode_name(opcode) { opcode, #opcode }
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