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Subject[PATCH v6 41/43] compat_ioctl: move SG_GET_REQUEST_TABLE handling
Date
SG_GET_REQUEST_TABLE is now the last ioctl command that needs a conversion
handler. This is only used in a single file, so the implementation should
be there.

I'm trying to simplify it in the process, to get rid of
the compat_alloc_user_space() and extra copy, by adding a
put_compat_request_table() function instead, which copies the data in
the right format to user space.

Cc: linux-scsi@vger.kernel.org
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/scsi/sg.c | 40 ++++++++++++++++++++++++++++-----
fs/compat_ioctl.c | 57 +----------------------------------------------
2 files changed, 36 insertions(+), 61 deletions(-)

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 8ae096af2667..9e4ef22b3579 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -889,6 +889,33 @@ sg_fill_request_table(Sg_fd *sfp, sg_req_info_t *rinfo)
}
}

+#ifdef CONFIG_COMPAT
+struct compat_sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */
+ char req_state;
+ char orphan;
+ char sg_io_owned;
+ char problem;
+ int pack_id;
+ compat_uptr_t usr_ptr;
+ unsigned int duration;
+ int unused;
+};
+
+static int put_compat_request_table(struct compat_sg_req_info __user *o,
+ struct sg_req_info *rinfo)
+{
+ int i;
+ for (i = 0; i < SG_MAX_QUEUE; i++) {
+ if (copy_to_user(o + i, rinfo + i, offsetof(sg_req_info_t, usr_ptr)) ||
+ put_user((uintptr_t)rinfo[i].usr_ptr, &o[i].usr_ptr) ||
+ put_user(rinfo[i].duration, &o[i].duration) ||
+ put_user(rinfo[i].unused, &o[i].unused))
+ return -EFAULT;
+ }
+ return 0;
+}
+#endif
+
static long
sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
{
@@ -1069,9 +1096,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
val = (sdp->device ? 1 : 0);
return put_user(val, ip);
case SG_GET_REQUEST_TABLE:
- if (!access_ok(p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
- return -EFAULT;
- else {
+ {
sg_req_info_t *rinfo;

rinfo = kcalloc(SG_MAX_QUEUE, SZ_SG_REQ_INFO,
@@ -1081,8 +1106,13 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
read_lock_irqsave(&sfp->rq_list_lock, iflags);
sg_fill_request_table(sfp, rinfo);
read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
- result = __copy_to_user(p, rinfo,
- SZ_SG_REQ_INFO * SG_MAX_QUEUE);
+ #ifdef CONFIG_COMPAT
+ if (in_compat_syscall())
+ result = put_compat_request_table(p, rinfo);
+ else
+ #endif
+ result = copy_to_user(p, rinfo,
+ SZ_SG_REQ_INFO * SG_MAX_QUEUE);
result = result ? -EFAULT : 0;
kfree(rinfo);
return result;
diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index 3cf8b6d113c3..9ae90d728c0f 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -52,53 +52,6 @@

#include <linux/sort.h>

-#ifdef CONFIG_BLOCK
-static int do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
- int err;
-
- err = security_file_ioctl(file, cmd, arg);
- if (err)
- return err;
-
- return vfs_ioctl(file, cmd, arg);
-}
-
-struct compat_sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */
- char req_state;
- char orphan;
- char sg_io_owned;
- char problem;
- int pack_id;
- compat_uptr_t usr_ptr;
- unsigned int duration;
- int unused;
-};
-
-static int sg_grt_trans(struct file *file,
- unsigned int cmd, struct compat_sg_req_info __user *o)
-{
- int err, i;
- sg_req_info_t __user *r;
- r = compat_alloc_user_space(sizeof(sg_req_info_t)*SG_MAX_QUEUE);
- err = do_ioctl(file, cmd, (unsigned long)r);
- if (err < 0)
- return err;
- for (i = 0; i < SG_MAX_QUEUE; i++) {
- void __user *ptr;
- int d;
-
- if (copy_in_user(o + i, r + i, offsetof(sg_req_info_t, usr_ptr)) ||
- get_user(ptr, &r[i].usr_ptr) ||
- get_user(d, &r[i].duration) ||
- put_user((u32)(unsigned long)(ptr), &o[i].usr_ptr) ||
- put_user(d, &o[i].duration))
- return -EFAULT;
- }
- return err;
-}
-#endif /* CONFIG_BLOCK */
-
/*
* simple reversible transform to make our table more evenly
* distributed after sorting.
@@ -121,6 +74,7 @@ COMPATIBLE_IOCTL(SCSI_IOCTL_GET_PCI)
#ifdef CONFIG_BLOCK
/* SG stuff */
COMPATIBLE_IOCTL(SG_IO)
+COMPATIBLE_IOCTL(SG_GET_REQUEST_TABLE)
COMPATIBLE_IOCTL(SG_SET_TIMEOUT)
COMPATIBLE_IOCTL(SG_GET_TIMEOUT)
COMPATIBLE_IOCTL(SG_EMULATED_HOST)
@@ -156,15 +110,6 @@ COMPATIBLE_IOCTL(SG_GET_KEEP_ORPHAN)
static long do_ioctl_trans(unsigned int cmd,
unsigned long arg, struct file *file)
{
-#ifdef CONFIG_BLOCK
- void __user *argp = compat_ptr(arg);
-
- switch (cmd) {
- case SG_GET_REQUEST_TABLE:
- return sg_grt_trans(file, cmd, argp);
- }
-#endif
-
return -ENOIOCTLCMD;
}

--
2.20.0
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