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| author | Joe Perches <joe@perches.com> | 2017-05-08 15:55:36 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-05-08 17:15:10 -0700 |
| commit | 0b523769ebb9473c60df1b0f70615aa82ebac2c9 (patch) | |
| tree | 7e9d9ac957dffd3a98750d4a82ece52286692774 | |
| parent | cd8618ab3df3ac6018cecb9dc626ff72c39eb503 (diff) | |
| download | lwn-0b523769ebb9473c60df1b0f70615aa82ebac2c9.tar.gz lwn-0b523769ebb9473c60df1b0f70615aa82ebac2c9.zip | |
checkpatch: add ability to find bad uses of vsprintf %p<foo> extensions
%pK was at least once misused at %pk in an out-of-tree module. This
lead to some security concerns. Add the ability to track single and
multiple line statements for misuses of %p<foo>.
[akpm@linux-foundation.org: add helpful comment into lib/vsprintf.c]
[akpm@linux-foundation.org: text tweak]
Link: http://lkml.kernel.org/r/163a690510e636a23187c0dc9caa09ddac6d4cde.1488228427.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: William Roberts <william.c.roberts@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | lib/vsprintf.c | 3 | ||||
| -rwxr-xr-x | scripts/checkpatch.pl | 26 |
2 files changed, 29 insertions, 0 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 176641cc549d..2d41de3f98a1 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1477,6 +1477,9 @@ int kptr_restrict __read_mostly; * by an extra set of alphanumeric characters that are extended format * specifiers. * + * Please update scripts/checkpatch.pl when adding/removing conversion + * characters. (Search for "check for vsprintf extension"). + * * Right now we handle: * * - 'F' For symbolic function descriptor pointers with offset diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 30eeba4f1602..732bb3e2fe9a 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -5663,6 +5663,32 @@ sub process { } } + # check for vsprintf extension %p<foo> misuses + if ($^V && $^V ge 5.10.0 && + defined $stat && + $stat =~ /^\+(?![^\{]*\{\s*).*\b(\w+)\s*\(.*$String\s*,/s && + $1 !~ /^_*volatile_*$/) { + my $bad_extension = ""; + 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(?![\WFfSsBKRraEhMmIiUDdgVCbGN]).)/) { + $bad_extension = $1; + last; + } + } + if ($bad_extension ne "") { + my $stat_real = raw_line($linenr, 0); + for (my $count = $linenr + 1; $count <= $lc; $count++) { + $stat_real = $stat_real . "\n" . raw_line($count, 0); + } + WARN("VSPRINTF_POINTER_EXTENSION", + "Invalid vsprintf pointer extension '$bad_extension'\n" . "$here\n$stat_real\n"); + } + } + # Check for misused memsets if ($^V && $^V ge 5.10.0 && defined $stat && |