[PATCH 4/9] iov_iter: transparently handle compat iovecs in import_iovec

From: Christoph Hellwig
Date: Fri Sep 25 2020 - 00:52:20 EST

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In reply to: Christoph Hellwig: "let import_iovec deal with compat_iovecs as well v4"
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Use in compat_syscall to import either native or the compat iovecs, and
remove the now superflous compat_import_iovec.

This removes the need for special compat logic in most callers, and
the remaining ones can still be simplified by using __import_iovec
with a bool compat parameter.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
block/scsi_ioctl.c | 12 ++----------
drivers/scsi/sg.c | 9 +--------
fs/aio.c | 8 ++------
fs/io_uring.c | 20 ++++++++------------
fs/read_write.c | 6 ++++--
fs/splice.c | 2 +-
include/linux/uio.h | 8 --------
lib/iov_iter.c | 14 ++------------
mm/process_vm_access.c | 3 ++-
net/compat.c | 4 ++--
security/keys/compat.c | 5 ++---
11 files changed, 26 insertions(+), 65 deletions(-)

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index ef722f04f88a93..e08df86866ee5d 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -333,16 +333,8 @@ static int sg_io(struct request_queue *q, struct gendisk *bd_disk,
struct iov_iter i;
struct iovec *iov = NULL;

-#ifdef CONFIG_COMPAT
- if (in_compat_syscall())
- ret = compat_import_iovec(rq_data_dir(rq),
- hdr->dxferp, hdr->iovec_count,
- 0, &iov, &i);
- else
-#endif
- ret = import_iovec(rq_data_dir(rq),
- hdr->dxferp, hdr->iovec_count,
- 0, &iov, &i);
+ ret = import_iovec(rq_data_dir(rq), hdr->dxferp,
+ hdr->iovec_count, 0, &iov, &i);
if (ret < 0)
goto out_free_cdb;

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 20472aaaf630a4..bfa8d77322d732 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1820,14 +1820,7 @@ sg_start_req(Sg_request *srp, unsigned char *cmd)
struct iovec *iov = NULL;
struct iov_iter i;

-#ifdef CONFIG_COMPAT
- if (in_compat_syscall())
- res = compat_import_iovec(rw, hp->dxferp, iov_count,
- 0, &iov, &i);
- else
-#endif
- res = import_iovec(rw, hp->dxferp, iov_count,
- 0, &iov, &i);
+ res = import_iovec(rw, hp->dxferp, iov_count, 0, &iov, &i);
if (res < 0)
return res;

diff --git a/fs/aio.c b/fs/aio.c
index d5ec303855669d..c45c20d875388c 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1489,12 +1489,8 @@ static ssize_t aio_setup_rw(int rw, const struct iocb *iocb,
*iovec = NULL;
return ret;
}
-#ifdef CONFIG_COMPAT
- if (compat)
- return compat_import_iovec(rw, buf, len, UIO_FASTIOV, iovec,
- iter);
-#endif
- return import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter);
+
+ return __import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter, compat);
}

static inline void aio_rw_done(struct kiocb *req, ssize_t ret)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 8b426aa29668cb..8c27dc28da182a 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2852,13 +2852,8 @@ static ssize_t __io_import_iovec(int rw, struct io_kiocb *req,
return ret;
}

-#ifdef CONFIG_COMPAT
- if (req->ctx->compat)
- return compat_import_iovec(rw, buf, sqe_len, UIO_FASTIOV,
- iovec, iter);
-#endif
-
- return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter);
+ return __import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter,
+ req->ctx->compat);
}

static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
@@ -4200,8 +4195,9 @@ static int __io_recvmsg_copy_hdr(struct io_kiocb *req,
sr->len);
iomsg->iov = NULL;
} else {
- ret = import_iovec(READ, uiov, iov_len, UIO_FASTIOV,
- &iomsg->iov, &iomsg->msg.msg_iter);
+ ret = __import_iovec(READ, uiov, iov_len, UIO_FASTIOV,
+ &iomsg->iov, &iomsg->msg.msg_iter,
+ false);
if (ret > 0)
ret = 0;
}
@@ -4241,9 +4237,9 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
sr->len = iomsg->iov[0].iov_len;
iomsg->iov = NULL;
} else {
- ret = compat_import_iovec(READ, uiov, len, UIO_FASTIOV,
- &iomsg->iov,
- &iomsg->msg.msg_iter);
+ ret = __import_iovec(READ, (struct iovec __user *)uiov, len,
+ UIO_FASTIOV, &iomsg->iov,
+ &iomsg->msg.msg_iter, true);
if (ret < 0)
return ret;
}
diff --git a/fs/read_write.c b/fs/read_write.c
index e5e891a88442ef..0a68037580b455 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1078,7 +1078,8 @@ static size_t compat_readv(struct file *file,
struct iov_iter iter;
ssize_t ret;

- ret = compat_import_iovec(READ, vec, vlen, UIO_FASTIOV, &iov, &iter);
+ ret = import_iovec(READ, (const struct iovec __user *)vec, vlen,
+ UIO_FASTIOV, &iov, &iter);
if (ret >= 0) {
ret = do_iter_read(file, &iter, pos, flags);
kfree(iov);
@@ -1186,7 +1187,8 @@ static size_t compat_writev(struct file *file,
struct iov_iter iter;
ssize_t ret;

- ret = compat_import_iovec(WRITE, vec, vlen, UIO_FASTIOV, &iov, &iter);
+ ret = import_iovec(WRITE, (const struct iovec __user *)vec, vlen,
+ UIO_FASTIOV, &iov, &iter);
if (ret >= 0) {
file_start_write(file);
ret = do_iter_write(file, &iter, pos, flags);
diff --git a/fs/splice.c b/fs/splice.c
index d7c8a7c4db07ff..132d42b9871f9b 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1387,7 +1387,7 @@ COMPAT_SYSCALL_DEFINE4(vmsplice, int, fd, const struct compat_iovec __user *, io
if (error)
return error;

- error = compat_import_iovec(type, iov32, nr_segs,
+ error = import_iovec(type, (struct iovec __user *)iov32, nr_segs,
ARRAY_SIZE(iovstack), &iov, &iter);
if (error >= 0) {
error = do_vmsplice(f.file, &iter, flags);
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 92c11fe41c6228..daedc61ad3706e 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -275,14 +275,6 @@ ssize_t import_iovec(int type, const struct iovec __user *uvec,
ssize_t __import_iovec(int type, const struct iovec __user *uvec,
unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
struct iov_iter *i, bool compat);
-
-#ifdef CONFIG_COMPAT
-struct compat_iovec;
-ssize_t compat_import_iovec(int type, const struct compat_iovec __user * uvector,
- unsigned nr_segs, unsigned fast_segs,
- struct iovec **iov, struct iov_iter *i);
-#endif
-
int import_single_range(int type, void __user *buf, size_t len,
struct iovec *iov, struct iov_iter *i);

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index d5d8afe31fca16..8c51e1b03814a3 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1806,21 +1806,11 @@ ssize_t import_iovec(int type, const struct iovec __user *uvec,
unsigned nr_segs, unsigned fast_segs,
struct iovec **iovp, struct iov_iter *i)
{
- return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, false);
+ return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i,
+ in_compat_syscall());
}
EXPORT_SYMBOL(import_iovec);

-#ifdef CONFIG_COMPAT
-ssize_t compat_import_iovec(int type, const struct compat_iovec __user *uvec,
- unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
- struct iov_iter *i)
-{
- return __import_iovec(type, (const struct iovec __user *)uvec, nr_segs,
- fast_segs, iovp, i, true);
-}
-EXPORT_SYMBOL(compat_import_iovec);
-#endif
-
int import_single_range(int rw, void __user *buf, size_t len,
struct iovec *iov, struct iov_iter *i)
{
diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index 5e728c20c2bead..3f2156aab44263 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -326,7 +326,8 @@ compat_process_vm_rw(compat_pid_t pid,
if (flags != 0)
return -EINVAL;

- rc = compat_import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter);
+ rc = import_iovec(dir, (const struct iovec __user *)lvec, liovcnt,
+ UIO_FASTIOV, &iov_l, &iter);
if (rc < 0)
return rc;
if (!iov_iter_count(&iter))
diff --git a/net/compat.c b/net/compat.c
index 95ce707a30a31d..ddd15af3a2837b 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -98,8 +98,8 @@ int get_compat_msghdr(struct msghdr *kmsg,
if (err)
return err;

- err = compat_import_iovec(save_addr ? READ : WRITE, compat_ptr(ptr),
- len, UIO_FASTIOV, iov, &kmsg->msg_iter);
+ err = import_iovec(save_addr ? READ : WRITE, compat_ptr(ptr), len,
+ UIO_FASTIOV, iov, &kmsg->msg_iter);
return err < 0 ? err : 0;
}

diff --git a/security/keys/compat.c b/security/keys/compat.c
index 6ee9d8f6a4a5bb..7ae531db031cf8 100644
--- a/security/keys/compat.c
+++ b/security/keys/compat.c
@@ -33,9 +33,8 @@ static long compat_keyctl_instantiate_key_iov(
if (!_payload_iov)
ioc = 0;

- ret = compat_import_iovec(WRITE, _payload_iov, ioc,
- ARRAY_SIZE(iovstack), &iov,
- &from);
+ ret = import_iovec(WRITE, (const struct iovec __user *)_payload_iov,
+ ioc, ARRAY_SIZE(iovstack), &iov, &from);
if (ret < 0)
return ret;

--
2.28.0

Next message: Christoph Hellwig: "[PATCH 6/9] fs: remove the compat readv/writev syscalls"
Previous message: Kishon Vijay Abraham I: "Re: [PATCH 5/6] mmc: sdhci_am654: Add support for software tuning"
In reply to: Christoph Hellwig: "let import_iovec deal with compat_iovecs as well v4"
Next in thread: Christoph Hellwig: "[PATCH 6/9] fs: remove the compat readv/writev syscalls"
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