aio: fix the compat vectored operations

The aio compat code was not converting the struct iovecs from 32bit to
64bit pointers, causing either EINVAL to be returned from io_getevents, or
EFAULT as the result of the I/O.  This patch passes a compat flag to
io_submit to signal that pointer conversion is necessary for a given iocb
array.

A variant of this was tested by Michael Tokarev.  I have also updated the
libaio test harness to exercise this code path with good success.
Further, I grabbed a copy of ltp and ran the
testcases/kernel/syscall/readv and writev tests there (compiled with -m32
on my 64bit system).  All seems happy, but extra eyes on this would be
welcome.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix CONFIG_COMPAT=n build]
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Reported-by: Michael Tokarev <mjt@tls.msk.ru>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: <stable@kernel.org>		[2.6.35.1]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 41 insertions, 24 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 1cf12b3dd83a..48fdeebdb544 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -36,6 +36,7 @@
 #include <linux/blkdev.h>
 #include <linux/mempool.h>
 #include <linux/hash.h>
+#include <linux/compat.h>
 
 #include <asm/kmap_types.h>
 #include <asm/uaccess.h>
@@ -1384,13 +1385,22 @@ static ssize_t aio_fsync(struct kiocb *iocb)
         return ret;
 }
 
-static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb)
+static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat)
 {
         ssize_t ret;
 
-        ret = rw_copy_check_uvector(type, (struct iovec __user *)kiocb->ki_buf,
-                                    kiocb->ki_nbytes, 1,
-                                    &kiocb->ki_inline_vec, &kiocb->ki_iovec);
+#ifdef CONFIG_COMPAT
+        if (compat)
+                ret = compat_rw_copy_check_uvector(type,
+                                (struct compat_iovec __user *)kiocb->ki_buf,
+                                kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
+                                &kiocb->ki_iovec);
+        else
+#endif
+                ret = rw_copy_check_uvector(type,
+                                (struct iovec __user *)kiocb->ki_buf,
+                                kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
+                                &kiocb->ki_iovec);
         if (ret < 0)
                 goto out;
 
@@ -1420,7 +1430,7 @@ static ssize_t aio_setup_single_vector(struct kiocb *kiocb)
  *      Performs the initial checks and aio retry method
  *      setup for the kiocb at the time of io submission.
  */
-static ssize_t aio_setup_iocb(struct kiocb *kiocb)
+static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat)
 {
         struct file *file = kiocb->ki_filp;
         ssize_t ret = 0;
@@ -1469,7 +1479,7 @@ static ssize_t aio_setup_iocb(struct kiocb *kiocb)
                 ret = security_file_permission(file, MAY_READ);
                 if (unlikely(ret))
                         break;
-                ret = aio_setup_vectored_rw(READ, kiocb);
+                ret = aio_setup_vectored_rw(READ, kiocb, compat);
                 if (ret)
                         break;
                 ret = -EINVAL;
@@ -1483,7 +1493,7 @@ static ssize_t aio_setup_iocb(struct kiocb *kiocb)
                 ret = security_file_permission(file, MAY_WRITE);
                 if (unlikely(ret))
                         break;
-                ret = aio_setup_vectored_rw(WRITE, kiocb);
+                ret = aio_setup_vectored_rw(WRITE, kiocb, compat);
                 if (ret)
                         break;
                 ret = -EINVAL;
@@ -1548,7 +1558,8 @@ static void aio_batch_free(struct hlist_head *batch_hash)
 }
 
 static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
-                         struct iocb *iocb, struct hlist_head *batch_hash)
+                         struct iocb *iocb, struct hlist_head *batch_hash,
+                         bool compat)
 {
         struct kiocb *req;
         struct file *file;
@@ -1609,7 +1620,7 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
         req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
         req->ki_opcode = iocb->aio_lio_opcode;
 
-        ret = aio_setup_iocb(req);
+        ret = aio_setup_iocb(req, compat);
 
         if (ret)
                 goto out_put_req;
@@ -1637,20 +1648,8 @@ out_put_req:
         return ret;
 }
 
-/* sys_io_submit:
- *      Queue the nr iocbs pointed to by iocbpp for processing.  Returns
- *      the number of iocbs queued.  May return -EINVAL if the aio_context
- *      specified by ctx_id is invalid, if nr is < 0, if the iocb at
- *      *iocbpp[0] is not properly initialized, if the operation specified
- *      is invalid for the file descriptor in the iocb.  May fail with
- *      -EFAULT if any of the data structures point to invalid data.  May
- *      fail with -EBADF if the file descriptor specified in the first
- *      iocb is invalid.  May fail with -EAGAIN if insufficient resources
- *      are available to queue any iocbs.  Will return 0 if nr is 0.  Will
- *      fail with -ENOSYS if not implemented.
- */
-SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
-                struct iocb __user * __user *, iocbpp)
+long do_io_submit(aio_context_t ctx_id, long nr,
+                  struct iocb __user *__user *iocbpp, bool compat)
 {
         struct kioctx *ctx;
         long ret = 0;
@@ -1687,7 +1686,7 @@ SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
                         break;
                 }
 
-                ret = io_submit_one(ctx, user_iocb, &tmp, batch_hash);
+                ret = io_submit_one(ctx, user_iocb, &tmp, batch_hash, compat);
                 if (ret)
                         break;
         }
@@ -1697,6 +1696,24 @@ SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
         return i ? i : ret;
 }
 
+/* sys_io_submit:
+ *      Queue the nr iocbs pointed to by iocbpp for processing.  Returns
+ *      the number of iocbs queued.  May return -EINVAL if the aio_context
+ *      specified by ctx_id is invalid, if nr is < 0, if the iocb at
+ *      *iocbpp[0] is not properly initialized, if the operation specified
+ *      is invalid for the file descriptor in the iocb.  May fail with
+ *      -EFAULT if any of the data structures point to invalid data.  May
+ *      fail with -EBADF if the file descriptor specified in the first
+ *      iocb is invalid.  May fail with -EAGAIN if insufficient resources
+ *      are available to queue any iocbs.  Will return 0 if nr is 0.  Will
+ *      fail with -ENOSYS if not implemented.
+ */
+SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
+                struct iocb __user * __user *, iocbpp)
+{
+        return do_io_submit(ctx_id, nr, iocbpp, 0);
+}
+
 /* lookup_kiocb
  *      Finds a given iocb for cancellation.
  */