https://github.com/linux-pam/linux-pam/commit/e3b66a60e4209e019cf6a45f521858cec2dbefa1 From e3b66a60e4209e019cf6a45f521858cec2dbefa1 Mon Sep 17 00:00:00 2001 From: "Dmitry V. Levin" Date: Tue, 17 Jun 2025 13:00:00 +0000 Subject: [PATCH] pam_timestamp: fix compilation warning on some of 32-bit architectures On those of 32-bit architectures where glibc defines __WORDSIZE_TIME64_COMPAT32, struct utmp.ut_tv.tv_sec is unsigned, while time_t is signed, causing the following compiler diagnostics: pam_timestamp.c: In function 'check_login_time': pam_timestamp.c:247:55: warning: comparison of integer expressions of different signedness: 'time_t' {aka 'long int'} and '__uint32_t' {aka 'unsigned int'} [-Wsign-compare] 247 | if (oldest_login == 0 || oldest_login > ut->ut_tv.tv_sec) { Given that by its nature these values are treated as unsigned, fix this by zero-extending both values to unsigned long long before the comparison. --- modules/pam_timestamp/pam_timestamp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/modules/pam_timestamp/pam_timestamp.c b/modules/pam_timestamp/pam_timestamp.c index 0172d1ef9..030fa2b8f 100644 --- a/modules/pam_timestamp/pam_timestamp.c +++ b/modules/pam_timestamp/pam_timestamp.c @@ -244,7 +244,9 @@ check_login_time( if (strncmp(ruser, ut->ut_user, sizeof(ut->ut_user)) != 0) { continue; } - if (oldest_login == 0 || oldest_login > ut->ut_tv.tv_sec) { + if (oldest_login == 0 || + zero_extend_signed_to_ull(oldest_login) + > zero_extend_signed_to_ull(ut->ut_tv.tv_sec)) { oldest_login = ut->ut_tv.tv_sec; } }