From ee29bd5dc5b08427a919ff84eeb06ee4158a3ae2 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Mon, 15 Feb 2021 22:49:36 +0100 Subject: [PATCH] socket-util: tighten parsing of ifnames Numeric ifnames should be acceptable only if that's enabled by flag, and refused otherwise. Hence, let's parse as ifindex first, and if that works decide. Finally, let's refuse any numeric ifnames that are not valid ifindexs, but look like them. --- src/basic/socket-util.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/src/basic/socket-util.c b/src/basic/socket-util.c index 59039bea4ff..8267988ad9c 100644 --- a/src/basic/socket-util.c +++ b/src/basic/socket-util.c @@ -721,6 +721,10 @@ bool ifname_valid_full(const char *p, IfnameValidFlags flags) { if (isempty(p)) return false; + /* A valid ifindex? If so, it's valid iff IFNAME_VALID_NUMERIC is set */ + if (parse_ifindex(p) >= 0) + return flags & IFNAME_VALID_NUMERIC; + if (flags & IFNAME_VALID_ALTERNATIVE) { if (strlen(p) >= ALTIFNAMSIZ) return false; @@ -745,14 +749,10 @@ bool ifname_valid_full(const char *p, IfnameValidFlags flags) { numeric = numeric && (*t >= '0' && *t <= '9'); } - if (numeric) { - if (!(flags & IFNAME_VALID_NUMERIC)) - return false; - - /* Verify that the number is well-formatted and in range. */ - if (parse_ifindex(p) < 0) - return false; - } + /* It's fully numeric but didn't parse as valid ifindex above? if so, it must be too large or zero or + * so, let's refuse that. */ + if (numeric) + return false; return true; } -- 2.47.3