From c7776e708e796587f8e264bd51a7ffe74422c26b Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Tue, 22 Apr 2014 20:09:56 -0400 Subject: perform minimal sanity checks on zoneinfo files loaded via TZ variable previously, setting TZ to the pathname of a file which was not a valid zoneinfo file would usually cause programs using local time zone based operations to crash. the new code checks the file size and magic at the beginning of the file, which seems sufficient to prevent accidental misconfiguration from causing crashes. attempting to make fully-robust validation would be futile unless we wanted to drop use of mmap (shared zoneinfo) and instead read it into a local buffer, since such validation would be subject to race conditions with modification of the file. (cherry picked from commit c3d9d172b1fcd56c4d356798f4e3b4653076bcc3) --- src/time/__tz.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'src/time') diff --git a/src/time/__tz.c b/src/time/__tz.c index 9d56a618..f56ef305 100644 --- a/src/time/__tz.c +++ b/src/time/__tz.c @@ -171,6 +171,11 @@ static void do_tzset() } } } + if (map && (map_size < 44 || memcmp(map, "TZif", 4))) { + __munmap((void *)map, map_size); + map = 0; + s = __gmt; + } zi = map; if (map) { -- cgit v1.2.1