From 11b3dda5e8b6cde957a6410233f30d6c48582998 Mon Sep 17 00:00:00 2001 From: Richard Fitzgerald Date: Fri, 14 May 2021 17:12:03 +0100 Subject: 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 Reviewed-by: Petr Mladek Acked-by: Andy Shevchenko Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210514161206.30821-1-rf@opensource.cirrus.com --- lib/vsprintf.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'lib/vsprintf.c') diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 6c56c62fd9a5..af307588ad8b 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -3526,8 +3526,12 @@ 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)) -- cgit v1.2.3