On Fri, Jan 09, 2026 at 11:34:54AM +0100, Andy Spiegl wrote: > > That change was done here: > > https://salsa.debian.org/debian/dovecot/-/commit/74e7dcd8c01731861777005a6c49b9093aec19c6 > Thanks. > > > TIME_T_MAX_BITS is set to 31 because Debian on i386 uses a signed 32-bit > > integer for time_t. > Ok. But then, this line in ioloop.c has to be adapted on i386 as well? > > ioloop->next_max_time.tv_sec = (1ULL << (TIME_T_MAX_BITS-1)) - 1; > It is supposed to be a very large value, "infinity" but on i386 is 1073741823 > which corresponds to 2004-01-10 instead of 2038-01-19.
So, it turns out that dovecot doesn't correctly handle 32-bit signed time_t at all right now. If we attempt to make it work by setting TIME_T_MAX_BITS=31, it misbehaves in the manner described in this bug. If we set TIME_T_MAX_BITS=32, then the tm_is_too_large() function (src/lib-imap/imap-date.c) misbehaves by assuming that time_t is unsigned, in which case it ends up with a "maximum" value corresponding to Wed Dec 31 18:59:59 1969. The attached patch updates tm_is_too_large() to set the correct maximum unsigned 32-bit time_t correctly. In my testing, it resolves the issue described in this bug when TIME_T_MAX_BITS=32. Will you be able to test this patch? Trixie packages with version 1:2.4.1+dfsg1-6+deb13u2+32bit are available in my apt repo at https://people.debian.org/~noahm/repo/ The patch is also at https://salsa.debian.org/noahm/dovecot/-/commits/bug1124541 noah
From: Noah Meyerhans <[email protected]> Subject: [PATCH] Correctly handle signed 32-bit time_t types Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1124541 Forwarded: no dovecot handles 32-bit time_t in a couple of different ways, but neither quite works currently. Setting TIME_T_MAX_BITS to 31 isn't correctly handled in places where time_t values are constructed, for example in io_loop_get_wait_time(). Similarly, setting TIME_T_MAX_BITS = 32 and defining TIME_T_SIGNED is not correctly handled by tm_is_too_large(). This change fixes tm_is_too_large() to set max_time to the correct maximum date representable by a signed 32-bit time_t. Closes: #1124541 --- src/lib-imap/imap-date.c | 4 ++++ src/lib-imap/test-imap-date.c | 14 ++++++++------ 2 files changed, 12 insertions(+), 6 deletions(-) diff --git a/src/lib-imap/imap-date.c b/src/lib-imap/imap-date.c index c9262932c..df9d11605 100644 --- a/src/lib-imap/imap-date.c +++ b/src/lib-imap/imap-date.c @@ -86,7 +86,11 @@ static bool tm_is_too_large(const struct tm *tm, time_t *max_time_r) if (max_time == 0) { #if TIME_T_MAX_BITS == 32 +#ifdef TIME_T_SIGNED + max_time = ((time_t)1 << TIME_T_MAX_BITS - 1) - 1; +#else max_time = 0xffffffffUL; +#endif #elif TIME_T_MAX_BITS == 64 max_time = 0xffffffffffffffffULL; #else diff --git a/src/lib-imap/test-imap-date.c b/src/lib-imap/test-imap-date.c index 5a2a36402..94c1a820d 100644 --- a/src/lib-imap/test-imap-date.c +++ b/src/lib-imap/test-imap-date.c @@ -15,7 +15,7 @@ static void test_imap_date(void) } tests[] = { { "01-Jan-1970", 0 }, { "19-Jan-2038", 2147472000 }, -#if TIME_T_MAX_BITS >= 32 +#if TIME_T_MAX_BITS > 32 || !defined(TIME_T_SIGNED) { "07-Feb-2106", 4294944000 }, #endif #if TIME_T_MAX_BITS >= 37 @@ -25,10 +25,10 @@ static void test_imap_date(void) { "31-Dec-9999", 253402214400LL }, #endif /* conversions to maximum values */ -#if TIME_T_MAX_BITS == 31 +#if TIME_T_MAX_BITS == 32 && !defined(TIME_T_SIGNED) { "20-Jan-2038", 2147483647 }, { "31-Dec-9999", 2147483647 }, -#elif TIME_T_MAX_BITS == 32 +#elif TIME_T_MAX_BITS == 32 && !defined(TIME_T_SIGNED) { "08-Feb-2106", 4294967295 }, { "31-Dec-9999", 4294967295 }, #endif @@ -59,8 +59,10 @@ static void test_imap_datetime(void) } tests[] = { { "01-Jan-1970 00:00:00 +0000", 0, 0 }, { "19-Jan-2038 03:14:07 +0000", 2147483647, 0 }, - { "19-Jan-2038 05:14:07 +0200", 2147483647, 2*60 }, #if TIME_T_MAX_BITS >= 32 + { "19-Jan-2038 05:14:07 +0200", 2147483647, 2*60 }, +#endif +#if TIME_T_MAX_BITS > 32 || !defined(TIME_T_SIGNED) { "07-Feb-2106 06:28:15 +0000", 4294967295, 0 }, #endif #if TIME_T_MAX_BITS >= 37 @@ -71,10 +73,10 @@ static void test_imap_datetime(void) { "31-Dec-9999 23:59:59 -2359", 253402300799LL + 23*60*60 + 59*60, -23*60 - 59 }, #endif /* conversions to maximum values */ -#if TIME_T_MAX_BITS == 31 +#if TIME_T_MAX_BITS == 32 && defined(TIME_T_SIGNED) { "19-Jan-2038 03:14:08 +0000", 2147483647, 0 }, { "31-Dec-9999 23:59:59 -2359", 2147483647, -23*60 - 59 }, -#elif TIME_T_MAX_BITS == 32 +#elif TIME_T_MAX_BITS == 32 && !defined(TIME_T_SIGNED) { "07-Feb-2106 06:28:16 +0000", 4294967295, 0 }, { "31-Dec-9999 23:59:59 -2359", 4294967295, -23*60 - 59 }, #endif -- 2.47.3
