The patch titled
memdup_user(): introduce
has been added to the -mm tree. Its filename is
memdup_user-introduce.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: memdup_user(): introduce
From: Li Zefan <lizf@xxxxxxxxxxxxxx>
I notice there are many places doing copy_from_user() which follows
kmalloc():
dst = kmalloc(len, GFP_KERNEL);
if (!dst)
return -ENOMEM;
if (copy_from_user(dst, src, len)) {
kfree(dst);
return -EFAULT
}
memdup_user() is a wrapper of the above code. With this new function, we
don't have to write 'len' twice, which can lead to typos/mistakes. It
also produces smaller code and kernel text.
A quick grep shows 250+ places where memdup_user() *may* be used. I'll
prepare a patchset to do this conversion.
v1 -> v2: change the name from kmemdup_from_user to memdup_user.
Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Americo Wang <xiyou.wangcong@xxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/string.h | 1 +
mm/util.c | 26 ++++++++++++++++++++++++++
2 files changed, 27 insertions(+)
diff -puN include/linux/string.h~memdup_user-introduce include/linux/string.h
--- a/include/linux/string.h~memdup_user-introduce
+++ a/include/linux/string.h
@@ -12,6 +12,7 @@
#include <linux/stddef.h> /* for NULL */
extern char *strndup_user(const char __user *, long);
+extern void *memdup_user(const void __user *, size_t, gfp_t);
/*
* Include machine specific inline routines
diff -puN mm/util.c~memdup_user-introduce mm/util.c
--- a/mm/util.c~memdup_user-introduce
+++ a/mm/util.c
@@ -70,6 +70,32 @@ void *kmemdup(const void *src, size_t le
EXPORT_SYMBOL(kmemdup);
/**
+ * memdup_user - duplicate memory region from user space
+ *
+ * @src: source address in user space
+ * @len: number of bytes to copy
+ * @gfp: GFP mask to use
+ *
+ * Returns an ERR_PTR() on failure.
+ */
+void *memdup_user(const void __user *src, size_t len, gfp_t gfp)
+{
+ void *p;
+
+ p = kmalloc_track_caller(len, gfp);
+ if (!p)
+ return ERR_PTR(-ENOMEM);
+
+ if (copy_from_user(p, src, len)) {
+ kfree(p);
+ return ERR_PTR(-EFAULT);
+ }
+
+ return p;
+}
+EXPORT_SYMBOL(memdup_user);
+
+/**
* __krealloc - like krealloc() but don't free @p.
* @p: object to reallocate memory for.
* @new_size: how many bytes of memory are required.
_
Patches currently in -mm which might be from lizf@xxxxxxxxxxxxxx are
linux-next.patch
vfs-add-missing-unlock-in-sget.patch
memdup_user-introduce.patch
relax-ns_can_attach-checks-to-allow-attaching-to-grandchild-cgroups.patch
cgroup-css-id-support.patch
cgroup-css-id-support-remove-rcu_read_lock-from-css_get_next.patch
cgroup-fix-frequent-ebusy-at-rmdir.patch
cgroups-more-documentation-for-remount-and-release_agent.patch
cgroups-show-correct-file-mode.patch
cgroups-show-correct-file-mode-fix.patch
cgroups-dont-change-release_agent-when-remount-failed.patch
memcg-use-css-id.patch
memcg-hierarchical-stat.patch
memcg-fix-shrinking-memory-to-return-ebusy-by-fixing-retry-algorithm.patch
memcg-fix-oom-killer-under-memcg.patch
memcg-fix-oom-killer-under-memcg-fix2.patch
memcg-fix-oom-killer-under-memcg-fix.patch
memcg-show-memcg-information-during-oom.patch
memcg-show-memcg-information-during-oom-fix2.patch
memcg-show-memcg-information-during-oom-fix.patch
memcg-show-memcg-information-during-oom-fix-fix.patch
memcg-show-memcg-information-during-oom-fix-fix-checkpatch-fixes.patch
use-css-id-in-swap_cgroup-for-saving-memory-v4.patch
cpuset-fix-possible-races-in-cpu-memory-hotplug.patch
cgroups-add-data-field-to-struct-cgroup_scanner.patch
cpuset-rewrite-update_tasks_nodemask.patch
cpuset-avoid-changing-cpusets-mems-when-errno-returned.patch
cpuset-remove-struct-cpuset_hotplug_scanner.patch
cpusets-allow-cpusets-to-be-configured-built-on-non-smp-systems.patch
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