From: Nitin Gote <nitin.r.gote@xxxxxxxxx> 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. Acked-by: Kees Cook <keescook@xxxxxxxxxxxx> Signed-off-by: Nitin Gote <nitin.r.gote@xxxxxxxxx> --- Change log: v1->v2 - For string related apis, created different %deprecated_string_api and these will get emitted at CHECK Level using command line option -f/--file to avoid bad patched from novice script users. This patch is already reviewed by mailing list kernel-hardening@xxxxxxxxxxxxxxxxxx. Refer below link <https://www.openwall.com/lists/kernel-hardening/2019/07/03/4> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx> Documentation/process/deprecated.rst | 6 +++--- scripts/checkpatch.pl | 25 +++++++++++++++++++++++++ 2 files changed, 28 insertions(+), 3 deletions(-) diff --git a/Documentation/process/deprecated.rst b/Documentation/process/deprecated.rst index 49e0f64a3427..f564de3caf76 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 bb28b178d929..10bd72e99dc8 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -605,6 +605,21 @@ foreach my $entry (keys %deprecated_apis) { } $deprecated_apis_search = "(?:${deprecated_apis_search})"; +our %deprecated_string_apis = ( + "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 apis to speed up a loop below +our $deprecated_string_apis_search = ""; +foreach my $entry (keys %deprecated_string_apis) { + $deprecated_string_apis_search .= '|' if ($deprecated_string_apis_search ne ""); + $deprecated_string_apis_search .= $entry; +} +$deprecated_string_apis_search = "(?:${deprecated_string_apis_search})"; + our $mode_perms_world_writable = qr{ S_IWUGO | S_IWOTH | @@ -6446,6 +6461,16 @@ sub process { "Deprecated use of '$deprecated_api', prefer '$new_api' instead\n" . $herecurr); } +# check for string deprecated apis + if ($line =~ /\b($deprecated_string_apis_search)\b\s*\(/) { + my $deprecated_string_api = $1; + my $new_api = $deprecated_string_apis{$deprecated_string_api}; + $check = 1; + CHK("DEPRECATED_API", + "Deprecated use of '$deprecated_string_api', prefer '$new_api' instead\n" . $herecurr); + $check = 0; + } + # check for various structs that are normally const (ops, kgdb, device_tree) # and avoid what seem like struct definitions 'struct foo {' if ($line !~ /\bconst\b/ && -- 2.17.1
