Introduce a compat version of the struct `mmc_ioc_cmd` and struct `mmc_ioc_multi_cmd`. Also implement helper functions which convert between the native and compat versions of these two structs.
A subsequent patch will change the structs to enable it to support new architectures. On such architectures, the current struct layout must still be supported for compat tasks.
Signed-off-by: Akram Ahmad Akram.Ahmad@arm.com --- drivers/mmc/core/block.c | 107 ++++++++++++++++++++++++++++++++++++--- 1 file changed, 100 insertions(+), 7 deletions(-)
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index 2f8884e3d4c2..3d0440fe63df 100644 --- a/drivers/mmc/core/block.c +++ b/drivers/mmc/core/block.c @@ -101,6 +101,33 @@ struct mmc_blk_busy_data { u32 status; };
+static inline bool in_compat64(void) +{ + return IS_ENABLED(CONFIG_COMPAT64) && in_compat_syscall(); +} + +struct compat_mmc_ioc_cmd { + int write_flag; + int is_acmd; + __u32 opcode; + __u32 arg; + __u32 response[4]; + unsigned int flags; + unsigned int blksz; + unsigned int blocks; + unsigned int postsleep_min_us; + unsigned int postsleep_max_us; + unsigned int data_timeout_ns; + unsigned int cmd_timeout_ms; + __u32 __pad; + __u64 data_ptr; +}; + +struct compat_mmc_ioc_multi_cmd { + __u64 num_of_cmds; + struct compat_mmc_ioc_cmd cmds[]; +}; + /* * There is one mmc_blk_data per slot. */ @@ -401,6 +428,54 @@ struct mmc_blk_ioc_data { struct mmc_rpmb_data *rpmb; };
+/* + * Copy the data from a `compat_mmc_ioc_cmd` user pointer, `src` + * to kernel space, storing it in `native_cmd`. Returns 0 for + * a successful copy. + */ +static int get_mmc_ioc_cmd_from_compat64( + struct mmc_ioc_cmd *native_cmd, + void * __user src) +{ + struct compat_mmc_ioc_cmd compat_cmd = {}; + + if (copy_from_user(&compat_cmd, src, sizeof(struct compat_mmc_ioc_cmd))) + return -EFAULT; + + native_cmd->arg = compat_cmd.arg; + native_cmd->is_acmd = compat_cmd.is_acmd; + native_cmd->opcode = compat_cmd.opcode; + native_cmd->arg = compat_cmd.arg; + memcpy(native_cmd->response, compat_cmd.response, sizeof(compat_cmd.response)); + native_cmd->response[0] = compat_cmd.response[0]; + native_cmd->response[1] = compat_cmd.response[1]; + native_cmd->response[2] = compat_cmd.response[2]; + native_cmd->response[3] = compat_cmd.response[3]; + native_cmd->flags = compat_cmd.flags; + native_cmd->blksz = compat_cmd.blksz; + native_cmd->blocks = compat_cmd.blocks; + native_cmd->postsleep_min_us = compat_cmd.postsleep_min_us; + native_cmd->postsleep_max_us = compat_cmd.postsleep_max_us; + native_cmd->data_timeout_ns = compat_cmd.data_timeout_ns; + native_cmd->cmd_timeout_ms = compat_cmd.cmd_timeout_ms; + native_cmd->__pad = compat_cmd.__pad; + native_cmd->data_ptr = compat_cmd.data_ptr; + + return 0; +} + +static int mmc_ioc_cmd_copy_from_user( + struct mmc_ioc_cmd *to, + void * __user src) +{ + if (in_compat64()) + return get_mmc_ioc_cmd_from_compat64(to, src); + + if (copy_from_user(to, src, sizeof(*to))) + return -EFAULT; + return 0; +} + static struct mmc_blk_ioc_data *mmc_blk_ioctl_copy_from_user( struct mmc_ioc_cmd __user *user) { @@ -413,7 +488,7 @@ static struct mmc_blk_ioc_data *mmc_blk_ioctl_copy_from_user( goto out; }
- if (copy_from_user(&idata->ic, user, sizeof(idata->ic))) { + if (mmc_ioc_cmd_copy_from_user(&idata->ic, user)) { err = -EFAULT; goto idata_err; } @@ -449,8 +524,11 @@ static int mmc_blk_ioctl_copy_to_user(struct mmc_ioc_cmd __user *ic_ptr, { struct mmc_ioc_cmd *ic = &idata->ic;
- if (copy_to_user(&(ic_ptr->response), ic->response, - sizeof(ic->response))) + void __user *response_uptr = in_compat64() ? + &((struct compat_mmc_ioc_cmd __user *)ic_ptr)->response : + &ic_ptr->response; + + if (copy_to_user(response_uptr, ic->response, sizeof(*response_uptr))) return -EFAULT;
if (!idata->ic.write_flag) { @@ -666,20 +744,35 @@ static int mmc_blk_ioctl_cmd(struct mmc_blk_data *md, return ioc_err ? ioc_err : err; }
+static inline void __user *get_ith_mmc_ioc_cmd_uptr( + void __user *cmds_array, + unsigned int i) +{ + if (in_compat64()) + return (void __user *)&((struct compat_mmc_ioc_cmd __user *)cmds_array)[i]; + return (void __user *)&((struct mmc_ioc_cmd __user *)cmds_array)[i]; +} + static int mmc_blk_ioctl_multi_cmd(struct mmc_blk_data *md, struct mmc_ioc_multi_cmd __user *user, struct mmc_rpmb_data *rpmb) { struct mmc_blk_ioc_data **idata = NULL; - struct mmc_ioc_cmd __user *cmds = user->cmds; struct mmc_card *card; struct mmc_queue *mq; int err = 0, ioc_err = 0; __u64 num_of_cmds; unsigned int i, n; struct request *req; + void __user *ioc_cmds = in_compat64() ? + (void __user *)((struct compat_mmc_ioc_multi_cmd __user *)user)->cmds : + (void __user *)user->cmds; + + __u64 __user *num_of_cmds_uptr = in_compat64() ? + (__u64 __user *)&((struct compat_mmc_ioc_multi_cmd __user *)user)->num_of_cmds : + &user->num_of_cmds;
- if (copy_from_user(&num_of_cmds, &user->num_of_cmds, + if (copy_from_user(&num_of_cmds, num_of_cmds_uptr, sizeof(num_of_cmds))) return -EFAULT;
@@ -695,7 +788,7 @@ static int mmc_blk_ioctl_multi_cmd(struct mmc_blk_data *md, return -ENOMEM;
for (i = 0; i < n; i++) { - idata[i] = mmc_blk_ioctl_copy_from_user(&cmds[i]); + idata[i] = mmc_blk_ioctl_copy_from_user(get_ith_mmc_ioc_cmd_uptr(&ioc_cmds, i)); if (IS_ERR(idata[i])) { err = PTR_ERR(idata[i]); n = i; @@ -732,7 +825,7 @@ static int mmc_blk_ioctl_multi_cmd(struct mmc_blk_data *md,
/* copy to user if data and response */ for (i = 0; i < n && !err; i++) - err = mmc_blk_ioctl_copy_to_user(&cmds[i], idata[i]); + err = mmc_blk_ioctl_copy_to_user(get_ith_mmc_ioc_cmd_uptr(&ioc_cmds, i), idata[i]);
blk_mq_free_request(req);