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Subject[PATCH 2/2] aio: fix the compat vectored operations
Date
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.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
---
fs/aio.c | 63 +++++++++++++++++++++++++++++++-------------------
fs/compat.c | 2 +-
include/linux/aio.h | 5 ++++
3 files changed, 45 insertions(+), 25 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 1cf12b3..5a38805 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 +1385,20 @@ 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);
+ 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
+ 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 +1428,7 @@ 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 +1477,7 @@ 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 +1491,7 @@ 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 +1556,8 @@ 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 +1618,7 @@ 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 +1646,8 @@ 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 +1684,7 @@ 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;
}
@@ -1696,6 +1693,24 @@ SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
put_ioctx(ctx);
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.
diff --git a/fs/compat.c b/fs/compat.c
index ae0066d..7dd8952 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -673,7 +673,7 @@ compat_sys_io_submit(aio_context_t ctx_id, int nr, u32 __user *iocb)
iocb64 = compat_alloc_user_space(nr * sizeof(*iocb64));
ret = copy_iocb(nr, iocb, iocb64);
if (!ret)
- ret = sys_io_submit(ctx_id, nr, iocb64);
+ ret = do_io_submit(ctx_id, nr, iocb64, 1);
return ret;
}

diff --git a/include/linux/aio.h b/include/linux/aio.h
index 811dbb3..54b6ef8 100644
--- a/include/linux/aio.h
+++ b/include/linux/aio.h
@@ -212,6 +212,8 @@ extern void kick_iocb(struct kiocb *iocb);
extern int aio_complete(struct kiocb *iocb, long res, long res2);
struct mm_struct;
extern void exit_aio(struct mm_struct *mm);
+extern long do_io_submit(aio_context_t ctx_id, long nr,
+ struct iocb __user *__user * iocbpp, bool compat);
#else
static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; }
static inline int aio_put_req(struct kiocb *iocb) { return 0; }
@@ -219,6 +221,9 @@ static inline void kick_iocb(struct kiocb *iocb) { }
static inline int aio_complete(struct kiocb *iocb, long res, long res2) { return 0; }
struct mm_struct;
static inline void exit_aio(struct mm_struct *mm) { }
+static inline long do_io_submit(aio_context_t ctx_id, long nr,
+ struct iocb __user * __user * iocbpp,
+ bool compat) { }
#endif /* CONFIG_AIO */

static inline struct kiocb *list_kiocb(struct list_head *h)
--
1.6.2.5


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