lkml.org 
[lkml]   [2020]   [Sep]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 7/9 next] mm/process_vm_access: Use iovec_import() instead of import_iovec().
Date
iovec_import() has a safer calling convention than import_iovec().

Signed-off-by: David Laight <david.laight@aculab.com>
---
mm/process_vm_access.c | 81 ++++++++++++++++++++++--------------------
1 file changed, 42 insertions(+), 39 deletions(-)

diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index 1cc3d6f66b31..048637944d47 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -260,10 +260,10 @@ static ssize_t process_vm_rw(pid_t pid,
unsigned long riovcnt,
unsigned long flags, int vm_write)
{
- struct iovec iovstack_l[UIO_FASTIOV];
- struct iovec iovstack_r[UIO_FASTIOV];
- struct iovec *iov_l = iovstack_l;
- struct iovec *iov_r = iovstack_r;
+ struct iovec_cache cache_l;
+ struct iovec_cache cache_r;
+ struct iovec *iov_l;
+ struct iovec *iov_r;
struct iov_iter iter_l, iter_r;
ssize_t rc;
int dir = vm_write ? WRITE : READ;
@@ -272,24 +272,25 @@ static ssize_t process_vm_rw(pid_t pid,
return -EINVAL;

/* Check iovecs */
- rc = import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter_l);
- if (rc < 0)
- return rc;
- if (!iov_iter_count(&iter_l))
- goto free_iovecs;
-
- rc = import_iovec(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV, &iov_r, &iter_r);
- if (rc <= 0)
- goto free_iovecs;
-
- rc = process_vm_rw_core(pid, &iter_l, iter_r.iov, iter_r.nr_segs,
- flags, vm_write);
+ iov_l = iovec_import(dir, lvec, liovcnt, &cache_l, &iter_l);
+ if (IS_ERR(iov_l))
+ return PTR_ERR(iov_l);
+ if (!iov_iter_count(&iter_l)) {
+ rc = 0;
+ goto free_iovec_l;
+ }

-free_iovecs:
- if (iov_r != iovstack_r)
+ iov_r = iovec_import(CHECK_IOVEC_ONLY, rvec, riovcnt, &cache_r, &iter_r);
+ if (IS_ERR(iov_r)) {
+ rc = PTR_ERR(iov_r);
+ } else {
+ rc = process_vm_rw_core(pid, &iter_l, iter_r.iov,
+ iter_r.nr_segs, flags, vm_write);
kfree(iov_r);
- if (iov_l != iovstack_l)
- kfree(iov_l);
+ }
+
+free_iovec_l:
+ kfree(iov_l);

return rc;
}
@@ -319,10 +320,10 @@ compat_process_vm_rw(compat_pid_t pid,
unsigned long riovcnt,
unsigned long flags, int vm_write)
{
- struct iovec iovstack_l[UIO_FASTIOV];
- struct iovec iovstack_r[UIO_FASTIOV];
- struct iovec *iov_l = iovstack_l;
- struct iovec *iov_r = iovstack_r;
+ struct iovec_cache cache_l;
+ struct iovec_cache cache_r;
+ struct iovec *iov_l;
+ struct iovec *iov_r;
struct iov_iter iter_l, iter_r;
ssize_t rc = -EFAULT;
int dir = vm_write ? WRITE : READ;
@@ -330,23 +331,25 @@ 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_l);
- if (rc < 0)
- return rc;
- if (!iov_iter_count(&iter_l))
- goto free_iovecs;
- rc = compat_import_iovec(0, rvec, riovcnt, UIO_FASTIOV, &iov_r, &iter_r);
- if (rc <= 0)
- goto free_iovecs;
-
- rc = process_vm_rw_core(pid, &iter_l, iter_r.iov, iter_r.nr_segs,
- flags, vm_write);
+ iov_l = compat_iovec_import(dir, lvec, liovcnt, &cache_l, &iter_l);
+ if (IS_ERR(iov_l))
+ return PTR_ERR(iov_l);
+ if (!iov_iter_count(&iter_l)) {
+ rc = 0;
+ goto free_iovec_l;
+ }

-free_iovecs:
- if (iov_r != iovstack_r)
+ iov_r = compat_iovec_import(0, rvec, riovcnt, &cache_r, &iter_r);
+ if (IS_ERR(iov_r)) {
+ rc = PTR_ERR(iov_r);
+ } else {
+ rc = process_vm_rw_core(pid, &iter_l, iter_r.iov,
+ iter_r.nr_segs, flags, vm_write);
kfree(iov_r);
- if (iov_l != iovstack_l)
- kfree(iov_l);
+ }
+
+free_iovec_l:
+ kfree(iov_l);
return rc;
}

--
2.25.1
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

\
 
 \ /
  Last update: 2020-09-16 01:03    [W:0.033 / U:9.764 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site