Added warnings in checkpatch.pl script to :

1. Deprecate strcpy() in favor of strscpy().
2. Deprecate strlcpy() in favor of strscpy().
3. Deprecate strncpy() in favor of strscpy() or strscpy_pad().

Updated strncpy() section in Documentation/process/deprecated.rst
to cover strscpy_pad() case.

Signed-off-by: Nitin Gote <nitin.r.g...@intel.com>
---
 This patch is already reviewed by mailing list
 kernel-harden...@lists.openwall.com. Refer below link
 <https://www.openwall.com/lists/kernel-hardening/2019/07/03/4>
Acked-by: Kees Cook <keesc...@chromium.org>

 Documentation/process/deprecated.rst | 6 +++---
 scripts/checkpatch.pl                | 5 +++++
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/Documentation/process/deprecated.rst 
b/Documentation/process/deprecated.rst
index 49e0f64..f564de3 100644
--- a/Documentation/process/deprecated.rst
+++ b/Documentation/process/deprecated.rst
@@ -93,9 +93,9 @@ will be NUL terminated. This can lead to various linear read 
overflows
 and other misbehavior due to the missing termination. It also NUL-pads the
 destination buffer if the source contents are shorter than the destination
 buffer size, which may be a needless performance penalty for callers using
-only NUL-terminated strings. The safe replacement is :c:func:`strscpy`.
-(Users of :c:func:`strscpy` still needing NUL-padding will need an
-explicit :c:func:`memset` added.)
+only NUL-terminated strings. In this case, the safe replacement is
+:c:func:`strscpy`. If, however, the destination buffer still needs
+NUL-padding, the safe replacement is :c:func:`strscpy_pad`.
 
 If a caller is using non-NUL-terminated strings, :c:func:`strncpy()` can
 still be used, but destinations should be marked with the `__nonstring
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 342c7c7..3d80967 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -595,6 +595,11 @@ our %deprecated_apis = (
        "rcu_barrier_sched"                     => "rcu_barrier",
        "get_state_synchronize_sched"           => "get_state_synchronize_rcu",
        "cond_synchronize_sched"                => "cond_synchronize_rcu",
+       "strcpy"                                => "strscpy",
+       "strlcpy"                               => "strscpy",
+       "strncpy"                               => "strscpy, strscpy_pad or for
+       non-NUL-terminated strings, strncpy() can still be used, but
+       destinations should be marked with the __nonstring",
 );
 
 #Create a search pattern for all these strings to speed up a loop below
-- 
2.7.4

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