From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <1486783428.2192.44.camel@perches.com> From: Joe Perches Date: Fri, 10 Feb 2017 19:23:48 -0800 In-Reply-To: <476DC76E7D1DF2438D32BFADF679FC562305DC7B@ORSMSX103.amr.corp.intel.com> References: <1486755469-21573-1-git-send-email-william.c.roberts@intel.com> <1486757549.2192.20.camel@perches.com> <476DC76E7D1DF2438D32BFADF679FC562305C559@ORSMSX103.amr.corp.intel.com> <476DC76E7D1DF2438D32BFADF679FC562305C5BA@ORSMSX103.amr.corp.intel.com> <1486766996.2192.30.camel@perches.com> <476DC76E7D1DF2438D32BFADF679FC562305DC7B@ORSMSX103.amr.corp.intel.com> Content-Type: multipart/mixed; boundary="=-HI7W5xdedkxGCZmNQ6ML" Mime-Version: 1.0 Subject: [kernel-hardening] Re: [PATCH] checkpatch: add warning on %pk instead of %pK usage To: "Roberts, William C" , "linux-kernel@vger.kernel.org" , "apw@canonical.com" Cc: "kernel-hardening@lists.openwall.com" List-ID: --=-HI7W5xdedkxGCZmNQ6ML Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit On Sat, 2017-02-11 at 01:32 +0000, Roberts, William C wrote: > > > > By "normal" I'm referring to things that call into pointer(), just > > > casually looking I see bstr_printf vsnprintf kvasprintf, which would > > > be easy enough to add > > > > > > > What do you think is missing? sn?printf ? That's easy to add. > > > > > > The problem starts to get hairy when we think of how often folks roll > > > their own logging macros (see some small sampling at the end). > > > > > > I think we would want to add DEBUG DBG and sn?printf and maybe > > > consider dropping the \b on the regex so it's a bit more matchy but > > > still shouldn't end up matching on any ASM as you pointed out in the V2 nack. > > > > > > Ill break this down into: > > > 1. the patch as I know you'll take it, as you wrote it :-P 2. Adding > > > to the logging macros 3. exploring making it less matchy > > -Kees and Andrew they likely don't care about the rest of this... > > I have been working up a regex (I suck at these) to match C functions that have an invalid > %p format string and take arguments: > http://www.regexr.com/3f92k > > This could be a way to get better coverage in a more generic approach, thoughts? Maybe this: (attached too because Evolution is a bad email client) It's still kind of hacky, but it does find multiple line statements like: + printf(KERN_INFO + "a %pX", + foo); --- Subject: [PATCH] checkpatch: Add ability to find bad uses of vsprintf %p 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. Signed-off-by: Joe Perches --- scripts/checkpatch.pl | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index ad5ea5c545b2..0eaf6b8580d6 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -5676,6 +5676,32 @@ sub process { } } + # check for vsprintf extension %p 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 && -- --=-HI7W5xdedkxGCZmNQ6ML Content-Disposition: attachment; filename*0=0001-checkpatch-Add-ability-to-find-bad-uses-of-vsprintf-.pat; filename*1=ch Content-Type: text/x-patch; name="0001-checkpatch-Add-ability-to-find-bad-uses-of-vsprintf-.patch"; charset="ISO-8859-1" Content-Transfer-Encoding: base64 RnJvbSAzYmQ2ODY4NzExZWZlYjU4N2M1YzQ4ZTA2MGM0MTVhMTUwZmNjYWNhIE1vbiBTZXAgMTcg MDA6MDA6MDAgMjAwMQpNZXNzYWdlLUlkOiA8M2JkNjg2ODcxMWVmZWI1ODdjNWM0OGUwNjBjNDE1 YTE1MGZjY2FjYS4xNDg2NzgzMjI0LmdpdC5qb2VAcGVyY2hlcy5jb20+CkZyb206IEpvZSBQZXJj aGVzIDxqb2VAcGVyY2hlcy5jb20+CkRhdGU6IEZyaSwgMTAgRmViIDIwMTcgMTk6MTc6NDIgLTA4 MDAKU3ViamVjdDogW1BBVENIXSBjaGVja3BhdGNoOiBBZGQgYWJpbGl0eSB0byBmaW5kIGJhZCB1 c2VzIG9mIHZzcHJpbnRmICVwPGZvbz4KIGV4dGVuc2lvbnMKCiVwSyB3YXMgYXQgbGVhc3Qgb25j ZSBtaXN1c2VkIGF0ICVwayBpbiBhbiBvdXQtb2YtdHJlZSBtb2R1bGUuClRoaXMgbGVhZCB0byBz b21lIHNlY3VyaXR5IGNvbmNlcm5zLiAgQWRkIHRoZSBhYmlsaXR5IHRvIHRyYWNrCnNpbmdsZSBh bmQgbXVsdGlwbGUgbGluZSBzdGF0ZW1lbnRzIGZvciBtaXN1c2VzIG9mICVwPGZvbz4uCgpTaWdu ZWQtb2ZmLWJ5OiBKb2UgUGVyY2hlcyA8am9lQHBlcmNoZXMuY29tPgotLS0KIHNjcmlwdHMvY2hl Y2twYXRjaC5wbCB8IDI2ICsrKysrKysrKysrKysrKysrKysrKysrKysrCiAxIGZpbGUgY2hhbmdl ZCwgMjYgaW5zZXJ0aW9ucygrKQoKZGlmZiAtLWdpdCBhL3NjcmlwdHMvY2hlY2twYXRjaC5wbCBi L3NjcmlwdHMvY2hlY2twYXRjaC5wbAppbmRleCBhZDVlYTVjNTQ1YjIuLjBlYWY2Yjg1ODBkNiAx MDA3NTUKLS0tIGEvc2NyaXB0cy9jaGVja3BhdGNoLnBsCisrKyBiL3NjcmlwdHMvY2hlY2twYXRj aC5wbApAQCAtNTY3Niw3ICs1Njc2LDMyIEBAIHN1YiBwcm9jZXNzIHsKIAkJCX0KIAkJfQogCisJ CSMgY2hlY2sgZm9yIHZzcHJpbnRmIGV4dGVuc2lvbiAlcDxmb28+IG1pc3VzZXMKKwkJaWYgKCRe ViAmJiAkXlYgZ2UgNS4xMC4wICYmCisJCSAgICBkZWZpbmVkICRzdGF0ICYmCisJCSAgICAkc3Rh dCA9fiAvXlwrKD8hW15ce10qXHtccyopLipcYihcdyspXHMqXCguKiRTdHJpbmdccyosL3MgJiYK KwkJICAgICQxICF+IC9eXyp2b2xhdGlsZV8qJC8pIHsKKwkJCW15ICRiYWRfZXh0ZW5zaW9uID0g IiI7CisJCQlteSAkbGMgPSAkc3RhdCA9fiB0ckBcbkBAOworCQkJJGxjID0gJGxjICsgJGxpbmVu cjsKKwkJICAgICAgICBmb3IgKG15ICRjb3VudCA9ICRsaW5lbnI7ICRjb3VudCA8PSAkbGM7ICRj b3VudCsrKSB7CisJCQkJbXkgJGZtdCA9IGdldF9xdW90ZWRfc3RyaW5nKCRsaW5lc1skY291bnQg LSAxXSwgcmF3X2xpbmUoJGNvdW50LCAwKSk7CisJCQkJJGZtdCA9fiBzLyUlLy9nOworCQkJCWlm ICgkZm10ID1+IC8oXCVbXCpcZFwuXSpwKD8hW1xXRmZTc0JLUnJhRWhNbUlpVURkZ1ZDYkdOXSku KS8pIHsKKwkJCQkJJGJhZF9leHRlbnNpb24gPSAkMTsKKwkJCQkJbGFzdDsKKwkJCQl9CisJCQl9 CisJCQlpZiAoJGJhZF9leHRlbnNpb24gbmUgIiIpIHsKKwkJCQlteSAkc3RhdF9yZWFsID0gcmF3 X2xpbmUoJGxpbmVuciwgMCk7CisJCQkJZm9yIChteSAkY291bnQgPSAkbGluZW5yICsgMTsgJGNv dW50IDw9ICRsYzsgJGNvdW50KyspIHsKKwkJCQkJJHN0YXRfcmVhbCA9ICRzdGF0X3JlYWwgLiAi XG4iIC4gcmF3X2xpbmUoJGNvdW50LCAwKTsKKwkJCQl9CisJCQkJV0FSTigiVlNQUklOVEZfUE9J TlRFUl9FWFRFTlNJT04iLAorCQkJCSAgICAgIkludmFsaWQgdnNwcmludGYgcG9pbnRlciBleHRl bnNpb24gJyRiYWRfZXh0ZW5zaW9uJ1xuIiAuICIkaGVyZVxuJHN0YXRfcmVhbFxuIik7CisJCQl9 CisJCX0KKwogIyBDaGVjayBmb3IgbWlzdXNlZCBtZW1zZXRzCiAJCWlmICgkXlYgJiYgJF5WIGdl IDUuMTAuMCAmJgogCQkgICAgZGVmaW5lZCAkc3RhdCAmJgotLSAKMi4xMC4wLnJjMi4xLmcwNTM0 MzVjCgo= --=-HI7W5xdedkxGCZmNQ6ML--