File util-linux-ipcs-shmall-overflow-1.patch of Package util-linux.12160

From 7a08784ab053d6aa30db990cbec1fd35b34ed00a Mon Sep 17 00:00:00 2001
From: Vasilis Liaskovitis <vliaskovitis@suse.com>
Date: Fri, 15 Jan 2021 15:00:11 +0100
Subject: [PATCH 1/2] ipcs: Avoid shmall overflows

Avoid computing the number of bytes in shmall, by only
computing and printing the number of Kbytes. This avoids
some overflows, e.g.

$ echo "4503599627370496" > /proc/sys/kernel/shmall
$ ipcs -l | grep 'max total shared memory'
Before:
max total shared memory (kbytes) = 18014398509481980
After:
max total shared memory (kbytes) = 18014398509481984

$ echo "99993599627370500" > /proc/sys/kernel/shmall
99993599627370500
$ ipcs -l | grep 'max total shared memory'
Before:
max total shared memory (kbytes) = 18014398509481980
After:
max total shared memory (kbytes) = 399974398509482000

v1->v2:
  Print the non-overflow KB value only for IPC_UNIT_KB and
IPC_UNIT_DEFAULT.
  This way --bytes and --human options will still get an expected
output
  (but not avoiding the overflow).

Signed-off-by: Vasilis Liaskovitis <vliaskovitis@suse.com>
Signed-off-by: Karel Zak <kzak@redhat.com>
---
 sys-utils/ipcs.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

Index: util-linux-2.29.2/sys-utils/ipcs.c
===================================================================
--- util-linux-2.29.2.orig/sys-utils/ipcs.c
+++ util-linux-2.29.2/sys-utils/ipcs.c
@@ -198,6 +198,7 @@ static void do_shm (char format, int uni
 	case LIMITS:
 	{
 		struct ipc_limits lim;
+		uint64_t tmp, pgsz = getpagesize();
 
 		if (ipc_shm_get_limits(&lim)) {
 			printf (_("unable to fetch shared memory limits\n"));
@@ -207,6 +208,25 @@ static void do_shm (char format, int uni
 		printf (_("max number of segments = %ju\n"), lim.shmmni);
 		ipc_print_size(unit == IPC_UNIT_DEFAULT ? IPC_UNIT_KB : unit,
 			       _("max seg size"), lim.shmmax, "\n", 0);
+ 
+		if (unit == IPC_UNIT_KB || unit == IPC_UNIT_DEFAULT) {
+			ipc_print_size(IPC_UNIT_DEFAULT,
+			       _("max total shared memory (kbytes)"), (pgsz / 1024) *
+			       (uint64_t) lim.shmall, "\n", 0);
+		}
+		else {
+			tmp = (uint64_t) lim.shmall * pgsz;
+			/* overflow handling, at least we don't print ridiculous small values */
+			if (lim.shmall != 0 && tmp / lim.shmall != pgsz)
+			        tmp = UINT64_MAX - (UINT64_MAX % pgsz);
+
+			ipc_print_size(unit, _("max total shared memory"), tmp, "\n", 0);
+ 		}
+ 		ipc_print_size(unit == IPC_UNIT_DEFAULT ? IPC_UNIT_BYTES : unit,
+ 			       _("min seg size"), lim.shmmin, "\n", 0);
+
+
+
 		ipc_print_size(unit == IPC_UNIT_DEFAULT ? IPC_UNIT_KB : unit,
 			       _("max total shared memory"),
 			       (uint64_t) lim.shmall * getpagesize(), "\n", 0);