From patchwork Fri Jul 5 07:43:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lee Jones X-Patchwork-Id: 810731 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CBEE71442F4; Fri, 5 Jul 2024 07:43:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720165426; cv=none; b=s1odXfDM2mjFqxrjsTSqs9eG69la/Qz1CiiPu1oqkGQnE2NNp2SZAT6dv6UsrZQn3x+I5zXQTNCu43RJMnmJLeqXjTiYU7zpLx5rdG7DqV5Z8mpOVpu069wwpjnUnxZTPOIdLGkuhRRKKjbSao3Dl07Fwy8us2vtWCDypVRfrRs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720165426; c=relaxed/simple; bh=t4kXHg4frzsPSSTQ4jwgylMVLomLutzNdMNloKpmrgc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=WFaEGhHuTcN9itazeMEpAg4Pv4SG8sd3AFHuw9K7ZI6pua1b4vELsIVR2U22sTZKVoBfWQq9ZnLI9DBtSAdD74qPYDJgmYQ/PspOTKAb0Qw1ytgN7qkr2Y+mtxwfFamBnzlKiAcNn5AJx3JVS5sSkRkXAdRW63Bf9XSmWT4DgFE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=p3vaEXd4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="p3vaEXd4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 657D0C116B1; Fri, 5 Jul 2024 07:43:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720165426; bh=t4kXHg4frzsPSSTQ4jwgylMVLomLutzNdMNloKpmrgc=; h=From:To:Cc:Subject:Date:From; b=p3vaEXd48lD2RbryODvsQOyJuaC/Ld1MKO1HlXkg6KCn9JDRjMmFqZSGgSFVc5p5q Y6AYk/6gindaSpMl7jIXmTZNt34jyvMTcDSvTRkrfyl5RSfR9/KABGRmqCKeQJEmXm n7DoUZ0ll3PWj2HJDu8gou+M1yPSdNARNQb3CvjIIe/QPMWfwkdj12qScPEnp2/+yH 5XNGLO3St5IsmxT+Jr5fKlR8Sm5RkJzgXnqYJKYrJPT9r4xO98fsH+Z4Hel0SrQAAd P+hdURBAh/MP8jkXuXS0rNkggP9C5/EFe5CVww2z4MrNLJeau7AbpOfqVzCT3l6HO9 avm6+VpJXtzsA== From: Lee Jones To: lee@kernel.org, gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org Subject: [PATCH 1/1] usb: gadget: configfs: Prevent OOB read/write in usb_string_copy() Date: Fri, 5 Jul 2024 08:43:39 +0100 Message-ID: <20240705074339.633717-1-lee@kernel.org> X-Mailer: git-send-email 2.45.2.803.g4e1b14247a-goog Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Userspace provided string 's' could trivially have the length zero. Left unchecked this will firstly result in an OOB read in the form `if (str[0 - 1] == '\n') followed closely by an OOB write in the form `str[0 - 1] = '\0'`. There is already a validating check to catch strings that are too long. Let's supply an additional check for invalid strings that are too short. Signed-off-by: Lee Jones --- drivers/usb/gadget/configfs.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c index ce3cfa1f36f51..0e7c1e947c0a0 100644 --- a/drivers/usb/gadget/configfs.c +++ b/drivers/usb/gadget/configfs.c @@ -115,9 +115,12 @@ static int usb_string_copy(const char *s, char **s_copy) int ret; char *str; char *copy = *s_copy; + ret = strlen(s); if (ret > USB_MAX_STRING_LEN) return -EOVERFLOW; + if (ret < 1) + return -EINVAL; if (copy) { str = copy;