From 6437685130b68670888db1d0551f5464d56c4cec Mon Sep 17 00:00:00 2001 From: Greg Hudson Date: Sat, 22 Apr 2017 09:49:12 -0400 Subject: [PATCH] Add timestamp helper functions Add k5-int.h helper functions to manipulate krb5_timestamp values, avoiding undefined behavior and treating negative timestamp values as times between 2038 and 2106. Add a doxygen comment for krb5_timestamp indicating how third-party code should use it safely. ticket: 8352 (cherry picked from commit 58e9155060cd93b1a7557e37fbc9b077b76465c2) Signed-off-by: Robbie Harwood --- src/include/k5-int.h | 31 +++++++++++++++++++++++++++++++ src/include/krb5/krb5.hin | 9 +++++++++ 2 files changed, 40 insertions(+) diff --git a/src/include/k5-int.h b/src/include/k5-int.h index 06ca2b66d..82ee20760 100644 --- a/src/include/k5-int.h +++ b/src/include/k5-int.h @@ -2353,6 +2353,37 @@ k5memdup0(const void *in, size_t len, krb5_error_code *code) return ptr; } +/* Convert a krb5_timestamp to a time_t value, treating the negative range of + * krb5_timestamp as times between 2038 and 2106 (if time_t is 64-bit). */ +static inline time_t +ts2tt(krb5_timestamp timestamp) +{ + return (time_t)(uint32_t)timestamp; +} + +/* Return the delta between two timestamps (a - b) as a signed 32-bit value, + * without relying on undefined behavior. */ +static inline krb5_deltat +ts_delta(krb5_timestamp a, krb5_timestamp b) +{ + return (krb5_deltat)((uint32_t)a - (uint32_t)b); +} + +/* Increment a timestamp by a signed 32-bit interval, without relying on + * undefined behavior. */ +static inline krb5_timestamp +ts_incr(krb5_timestamp ts, krb5_deltat delta) +{ + return (krb5_timestamp)((uint32_t)ts + (uint32_t)delta); +} + +/* Return true if a comes after b. */ +static inline krb5_boolean +ts_after(krb5_timestamp a, krb5_timestamp b) +{ + return (uint32_t)a > (uint32_t)b; +} + krb5_error_code KRB5_CALLCONV krb5_get_credentials_for_user(krb5_context context, krb5_flags options, krb5_ccache ccache, diff --git a/src/include/krb5/krb5.hin b/src/include/krb5/krb5.hin index cf60d6c41..53ad85384 100644 --- a/src/include/krb5/krb5.hin +++ b/src/include/krb5/krb5.hin @@ -187,7 +187,16 @@ typedef krb5_int32 krb5_cryptotype; typedef krb5_int32 krb5_preauthtype; /* This may change, later on */ typedef krb5_int32 krb5_flags; + +/** + * Represents a timestamp in seconds since the POSIX epoch. This legacy type + * is used frequently in the ABI, but cannot represent timestamps after 2038 as + * a positive number. Code which uses this type should cast values of it to + * uint32_t so that negative values are treated as timestamps between 2038 and + * 2106 on platforms with 64-bit time_t. + */ typedef krb5_int32 krb5_timestamp; + typedef krb5_int32 krb5_deltat; /**