lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20210203165009.6299-1-rf@opensource.cirrus.com>
Date:   Wed, 3 Feb 2021 16:50:06 +0000
From:   Richard Fitzgerald <rf@...nsource.cirrus.com>
To:     <pmladek@...e.com>, <rostedt@...dmis.org>,
        <sergey.senozhatsky@...il.com>,
        <andriy.shevchenko@...ux.intel.com>, <linux@...musvillemoes.dk>,
        <shuah@...nel.org>
CC:     <linux-kernel@...r.kernel.org>, <linux-kselftest@...r.kernel.org>,
        <patches@...nsource.cirrus.com>,
        Richard Fitzgerald <rf@...nsource.cirrus.com>
Subject: [PATCH v4 1/4] lib: vsprintf: scanf: Negative number must have field width > 1

If a signed number field starts with a '-' the field width must be > 1,
or unlimited, to allow at least one digit after the '-'.

This patch adds a check for this. If a signed field starts with '-'
and field_width == 1 the scanf will quit.

It is ok for a signed number field to have a field width of 1 if it
starts with a digit. In that case the single digit can be converted.

Signed-off-by: Richard Fitzgerald <rf@...nsource.cirrus.com>
Reviewed-by: Petr Mladek <pmladek@...e.com>
---
 lib/vsprintf.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 3b53c73580c5..28bb26cd1f67 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -3434,8 +3434,12 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
 		str = skip_spaces(str);
 
 		digit = *str;
-		if (is_sign && digit == '-')
+		if (is_sign && digit == '-') {
+			if (field_width == 1)
+				break;
+
 			digit = *(str + 1);
+		}
 
 		if (!digit
 		    || (base == 16 && !isxdigit(digit))
-- 
2.20.1

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ