From 2eaea70111f65b16d55998386e4ceb4273c19eb4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= Date: Fri, 31 Mar 2023 14:46:50 +0200 Subject: [PATCH] Overhaul valid_field() e5905c4b ("Added control character check") introduced checking for control characters but had the logic inverted, so it rejects all characters that are not control ones. Cast the character to `unsigned char` before passing to the character checking functions to avoid UB. Use strpbrk(3) for the illegal character test and return early. Upstream-Status: Backport [https://github.com/shadow-maint/shadow/commit/2eaea70111f65b16d55998386e4ceb4273c19eb4] Signed-off-by: Xiangyu Chen --- lib/fields.c | 24 ++++++++++-------------- 1 file changed, 10 insertions(+), 14 deletions(-) diff --git a/lib/fields.c b/lib/fields.c index fb51b582..53929248 100644 --- a/lib/fields.c +++ b/lib/fields.c @@ -37,26 +37,22 @@ int valid_field (const char *field, const char *illegal) /* For each character of field, search if it appears in the list * of illegal characters. */ + if (illegal && NULL != strpbrk (field, illegal)) { + return -1; + } + + /* Search if there are non-printable or control characters */ for (cp = field; '\0' != *cp; cp++) { - if (strchr (illegal, *cp) != NULL) { + unsigned char c = *cp; + if (!isprint (c)) { + err = 1; + } + if (iscntrl (c)) { err = -1; break; } } - if (0 == err) { - /* Search if there are non-printable or control characters */ - for (cp = field; '\0' != *cp; cp++) { - if (!isprint (*cp)) { - err = 1; - } - if (!iscntrl (*cp)) { - err = -1; - break; - } - } - } - return err; } -- 2.34.1