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From: "Mickaël Salaün" <mic@digikod.net>
To: David Howells <dhowells@redhat.com>,
	David Woodhouse <dwmw2@infradead.org>
Cc: "Mickaël Salaün" <mic@digikod.net>,
	"David S . Miller" <davem@davemloft.net>,
	"Herbert Xu" <herbert@gondor.apana.org.au>,
	"James Morris" <jmorris@namei.org>,
	"Jarkko Sakkinen" <jarkko@kernel.org>,
	"Mickaël Salaün" <mic@linux.microsoft.com>,
	"Mimi Zohar" <zohar@linux.ibm.com>,
	"Serge E . Hallyn" <serge@hallyn.com>,
	keyrings@vger.kernel.org, linux-crypto@vger.kernel.org,
	linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-security-module@vger.kernel.org
Subject: [PATCH v1 1/9] certs: Fix blacklisted hexadecimal hash string check
Date: Fri, 20 Nov 2020 19:04:18 +0100	[thread overview]
Message-ID: <20201120180426.922572-2-mic@digikod.net> (raw)
In-Reply-To: <20201120180426.922572-1-mic@digikod.net>

From: Mickaël Salaün <mic@linux.microsoft.com>

When looking for a blacklisted hash, bin2hex() is used to transform a
binary hash to an ascii (lowercase) hexadecimal string.  This string is
then search for in the description of the keys from the blacklist
keyring.  When adding a key to the blacklist keyring,
blacklist_vet_description() checks the hash prefix and the hexadecimal
string, but not that this string is lowercase.  It is then valid to set
hashes with uppercase hexadecimal, which will be silently ignored by the
kernel.

Add an additional check to blacklist_vet_description() to check that
hexadecimal strings are in lowercase.

Cc: David Howells <dhowells@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
---
 certs/blacklist.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/certs/blacklist.c b/certs/blacklist.c
index 6514f9ebc943..4e1a58170d5c 100644
--- a/certs/blacklist.c
+++ b/certs/blacklist.c
@@ -37,7 +37,7 @@ static int blacklist_vet_description(const char *desc)
 found_colon:
 	desc++;
 	for (; *desc; desc++) {
-		if (!isxdigit(*desc))
+		if (!isxdigit(*desc) || isupper(*desc))
 			return -EINVAL;
 		n++;
 	}
-- 
2.29.2


  reply	other threads:[~2020-11-20 18:05 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-20 18:04 [PATCH v1 0/9] Enable root to update the blacklist keyring Mickaël Salaün
2020-11-20 18:04 ` Mickaël Salaün [this message]
2020-11-20 18:04 ` [PATCH v1 2/9] certs: Make blacklist_vet_description() more strict Mickaël Salaün
2020-11-20 18:04 ` [PATCH v1 3/9] certs: Factor out the blacklist hash creation Mickaël Salaün
2020-11-20 18:04 ` [PATCH v1 4/9] certs: Check that builtin blacklist hashes are valid Mickaël Salaün
2020-11-20 18:04 ` [PATCH v1 5/9] PKCS#7: Fix missing include Mickaël Salaün
2020-11-20 18:04 ` [PATCH v1 6/9] certs: Fix blacklist flag type confusion Mickaël Salaün
2020-11-20 18:04 ` [PATCH v1 7/9] certs: Allow root user to append signed hashes to the blacklist keyring Mickaël Salaün
2020-11-20 18:04 ` [PATCH v1 8/9] certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID Mickaël Salaün
2020-11-20 18:04 ` [PATCH v1 9/9] tools/certs: Add print-cert-tbs-hash.sh Mickaël Salaün
2020-11-30  2:40 ` [PATCH v1 0/9] Enable root to update the blacklist keyring Jarkko Sakkinen
2020-11-30  8:23   ` Mickaël Salaün
2020-12-02 16:44     ` Jarkko Sakkinen
2020-12-04 14:01   ` David Howells
2020-12-04 15:38     ` Jarkko Sakkinen
2020-12-04 14:05 ` [PATCH v1 1/9] certs: Fix blacklisted hexadecimal hash string check David Howells
2020-12-04 14:48   ` Mickaël Salaün
2020-12-04 14:06 ` [PATCH v1 5/9] PKCS#7: Fix missing include David Howells
2020-12-04 14:58   ` Mickaël Salaün
2020-12-04 14:09 ` [PATCH v1 2/9] certs: Make blacklist_vet_description() more strict David Howells
2020-12-04 14:59   ` Mickaël Salaün
2020-12-11 18:35   ` Mickaël Salaün
2020-12-04 14:11 ` [PATCH v1 8/9] certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID David Howells
2020-12-09 11:58 ` [PATCH v1 4/9] certs: Check that builtin blacklist hashes are valid David Howells
2020-12-11 18:32   ` Mickaël Salaün

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