From: "Tobin C. Harding" <me@xxxxxxxx> Subject: checkpatch: warn for use of %px Usage of the new %px specifier potentially leaks sensitive inforamtion. Printing kernel addresses exposes the kernel layout in memory, this is potentially exploitable. We have tools in the kernel to help us do the right thing. We can have checkpatch warn developers of potential dangers of using %px. Have checkpatch emit a warning for usage of specifier %px. Link: http://lkml.kernel.org/r/1519700648-23108-5-git-send-email-me@xxxxxxxx Signed-off-by: Tobin C. Harding <me@xxxxxxxx> Signed-off-by: Joe Perches <joe@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- scripts/checkpatch.pl | 48 ++++++++++++++++++++++++++-------------- 1 file changed, 32 insertions(+), 16 deletions(-) diff -puN scripts/checkpatch.pl~checkpatch-warn-for-use-of-%px scripts/checkpatch.pl --- a/scripts/checkpatch.pl~checkpatch-warn-for-use-of-%px +++ a/scripts/checkpatch.pl @@ -5812,29 +5812,45 @@ sub process { defined $stat && $stat =~ /^\+(?![^\{]*\{\s*).*\b(\w+)\s*\(.*$String\s*,/s && $1 !~ /^_*volatile_*$/) { - my $bad_extension = ""; + my $specifier; + my $extension; + my $bad_specifier = ""; + my $stat_real; + my $lc = $stat =~ tr@\n@@; $lc = $lc + $linenr; for (my $count = $linenr; $count <= $lc; $count++) { my $fmt = get_quoted_string($lines[$count - 1], raw_line($count, 0)); $fmt =~ s/%%//g; - if ($fmt =~ /(\%[\*\d\.]*p(?![\WSsBKRraEhMmIiUDdgVCbGNOx]).)/) { - $bad_extension = $1; - last; - } - } - if ($bad_extension ne "") { - my $stat_real = get_stat_real($linenr, $lc); - my $ext_type = "Invalid"; - my $use = ""; - if ($bad_extension =~ /p[Ff]/) { - $ext_type = "Deprecated"; - $use = " - use %pS instead"; - $use =~ s/pS/ps/ if ($bad_extension =~ /pf/); + + while ($fmt =~ /(\%[\*\d\.]*p(\w))/g) { + $specifier = $1; + $extension = $2; + if ($extension !~ /[SsBKRraEhMmIiUDdgVCbGNOx]/) { + $bad_specifier = $specifier; + last; + } + if ($extension eq "x" && !defined($stat_real)) { + if (!defined($stat_real)) { + $stat_real = get_stat_real($linenr, $lc); + } + WARN("VSPRINTF_SPECIFIER_PX", + "Using vsprintf specifier '\%px' potentially exposes the kernel memory layout, if you don't really need the address please consider using '\%p'.\n" . "$here\n$stat_real\n"); + } } + if ($bad_specifier ne "") { + my $stat_real = get_stat_real($linenr, $lc); + my $ext_type = "Invalid"; + my $use = ""; + if ($bad_specifier =~ /p[Ff]/) { + $ext_type = "Deprecated"; + $use = " - use %pS instead"; + $use =~ s/pS/ps/ if ($bad_specifier =~ /pf/); + } - WARN("VSPRINTF_POINTER_EXTENSION", - "$ext_type vsprintf pointer extension '$bad_extension'$use\n" . "$here\n$stat_real\n"); + WARN("VSPRINTF_POINTER_EXTENSION", + "$ext_type vsprintf pointer extension '$bad_specifier'$use\n" . "$here\n$stat_real\n"); + } } } _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
