[PATCH 5/6] sysvipc: Fix IPC_INFO and SHM_INFO handling [BZ #26636]
Adhemerval Zanella
adhemerval.zanella@linaro.org
Mon Sep 28 14:45:55 GMT 2020
Both commands are Linux extensions where the third argument is either
a 'struct shminfo' (IPC_INFO) or a 'struct shm_info' (SHM_INFO) instead
of 'struct shmid_ds'. And their information does not contain any time
related fields, so there is no need to extra conversion for __IPC_TIME64.
The regression testcase checks for Linux specifix SysV ipc message
control extension. For SHM_INFO it tries to match the values against the
tunable /proc values and for MSG_STAT/MSG_STAT_ANY it check if the create\
shared memory is within the global list returned by the kernel.
Checked on x86_64-linux-gnu and on i686-linux-gnu (Linux v5.4 and on
Linux v4.15).
---
sysdeps/unix/sysv/linux/Makefile | 2 +-
sysdeps/unix/sysv/linux/shmctl.c | 24 ++-
sysdeps/unix/sysv/linux/tst-sysvshm-linux.c | 195 ++++++++++++++++++++
3 files changed, 214 insertions(+), 7 deletions(-)
create mode 100644 sysdeps/unix/sysv/linux/tst-sysvshm-linux.c
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index a54eb75d74..5a78614457 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -101,7 +101,7 @@ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
tst-quota tst-sync_file_range tst-sysconf-iov_max tst-ttyname \
test-errno-linux tst-memfd_create tst-mlock2 tst-pkey \
tst-rlimit-infinity tst-ofdlocks tst-gettid tst-gettid-kill \
- tst-tgkill tst-sysvsem-linux tst-sysvmsg-linux
+ tst-tgkill tst-sysvsem-linux tst-sysvmsg-linux tst-sysvshm-linux
tests-internal += tst-ofdlocks-compat tst-sigcontext-get_pc
CFLAGS-tst-sigcontext-get_pc.c = -fasynchronous-unwind-tables
diff --git a/sysdeps/unix/sysv/linux/shmctl.c b/sysdeps/unix/sysv/linux/shmctl.c
index 76d88441f1..1d19a798b1 100644
--- a/sysdeps/unix/sysv/linux/shmctl.c
+++ b/sysdeps/unix/sysv/linux/shmctl.c
@@ -90,8 +90,15 @@ __shmctl64 (int shmid, int cmd, struct __shmid64_ds *buf)
struct kernel_shmid64_ds kshmid, *arg = NULL;
if (buf != NULL)
{
- shmid64_to_kshmid64 (buf, &kshmid);
- arg = &kshmid;
+ /* This is a Linux extension where kernel expects either a
+ 'struct shminfo' (IPC_INFO) or 'struct shm_info' (SHM_INFO). */
+ if (cmd == IPC_INFO || cmd == SHM_INFO)
+ arg = (struct kernel_shmid64_ds *) buf;
+ else
+ {
+ shmid64_to_kshmid64 (buf, &kshmid);
+ arg = &kshmid;
+ }
}
# ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
if (cmd == IPC_SET)
@@ -107,7 +114,6 @@ __shmctl64 (int shmid, int cmd, struct __shmid64_ds *buf)
switch (cmd)
{
- case IPC_INFO:
case IPC_STAT:
case SHM_STAT:
case SHM_STAT_ANY:
@@ -168,8 +174,15 @@ __shmctl (int shmid, int cmd, struct shmid_ds *buf)
struct __shmid64_ds shmid64, *buf64 = NULL;
if (buf != NULL)
{
- shmid_to_shmid64 (&shmid64, buf);
- buf64 = &shmid64;
+ /* This is a Linux extension where kernel expects either a
+ 'struct shminfo' (IPC_INFO) or 'struct shm_info' (SHM_INFO). */
+ if (cmd == IPC_INFO || cmd == SHM_INFO)
+ buf64 = (struct __shmid64_ds *) buf;
+ else
+ {
+ shmid_to_shmid64 (&shmid64, buf);
+ buf64 = &shmid64;
+ }
}
int ret = __shmctl64 (shmid, cmd, buf64);
@@ -178,7 +191,6 @@ __shmctl (int shmid, int cmd, struct shmid_ds *buf)
switch (cmd)
{
- case IPC_INFO:
case IPC_STAT:
case SHM_STAT:
case SHM_STAT_ANY:
diff --git a/sysdeps/unix/sysv/linux/tst-sysvshm-linux.c b/sysdeps/unix/sysv/linux/tst-sysvshm-linux.c
new file mode 100644
index 0000000000..0e89b5eeff
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-sysvshm-linux.c
@@ -0,0 +1,195 @@
+/* Basic tests for Linux SYSV shared memory extensions.
+ Copyright (C) 2020 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include <support/check.h>
+#include <support/temp_file.h>
+
+#define SHM_MODE 0644
+
+/* These are for the temporary file we generate. */
+static char *name;
+static int shmid;
+static long int pgsz;
+
+static void
+remove_shm (void)
+{
+ /* Enforce message queue removal in case of early test failure.
+ Ignore error since the shm may already have being removed. */
+ shmctl (shmid, IPC_RMID, NULL);
+}
+
+static void
+do_prepare (int argc, char *argv[])
+{
+ TEST_VERIFY_EXIT (create_temp_file ("tst-sysvshm.", &name) != -1);
+}
+
+#define PREPARE do_prepare
+
+struct test_shminfo
+{
+ unsigned long shmall;
+ unsigned long shmmax;
+ unsigned long shmmni;
+};
+
+/* It tries to obtain some system-wide SysV shared memory information from
+ /proc to check against IPC_INFO/SHM_INFO. The /proc only returns the
+ tunables value of SHMALL, SHMMAX, and SHMMNI. */
+
+static unsigned long
+read_proc_file (const char *file)
+{
+ FILE *f = fopen (file, "r");
+ if (f == NULL)
+ return -1;
+
+ unsigned long v;
+ int r = fscanf (f, "%lu", & v);
+ TEST_VERIFY_EXIT (r == 1);
+
+ fclose (f);
+ return v;
+}
+
+static bool
+read_shm_stat (struct test_shminfo *tipcinfo)
+{
+ tipcinfo->shmall = read_proc_file ("/proc/sys/kernel/shmall");
+ if (tipcinfo->shmall == -1)
+ return false;
+ tipcinfo->shmmax = read_proc_file ("/proc/sys/kernel/shmmax");
+ if (tipcinfo->shmmax == -1)
+ return false;
+ tipcinfo->shmmni = read_proc_file ("/proc/sys/kernel/shmmni");
+ if (tipcinfo->shmmni == -1)
+ return false;
+ return true;
+}
+
+
+/* Check if the message queue with IDX (index into the kernel's internal
+ array) matches the one with KEY. The CMD is either SHM_STAT or
+ SHM_STAT_ANY. */
+
+static bool
+check_shminfo (int idx, key_t key, int cmd)
+{
+ struct shmid_ds shminfo;
+ int sid = shmctl (idx, cmd, &shminfo);
+ /* Ignore unused array slot returned by the kernel or information from
+ unknown message queue. */
+ if ((sid == -1 && errno == EINVAL) || sid != shmid)
+ return false;
+
+ if (sid == -1)
+ FAIL_EXIT1 ("shmctl with %s failed: %m",
+ cmd == SHM_STAT ? "SHM_STAT" : "SHM_STAT_ANY");
+
+ if (shminfo.shm_perm.__key != key)
+ FAIL_EXIT1 ("shmid_ds::shm_perm::key (%d) != %d",
+ (int) shminfo.shm_perm.__key, (int) key);
+ if (shminfo.shm_perm.mode != SHM_MODE)
+ FAIL_EXIT1 ("shmid_ds::shm_perm::mode (%o) != %o",
+ shminfo.shm_perm.mode, SHM_MODE);
+ if (shminfo.shm_segsz != pgsz)
+ FAIL_EXIT1 ("shmid_ds::shm_segsz (%lu) != %lu",
+ (long unsigned) shminfo.shm_segsz, pgsz);
+
+ return true;
+}
+
+static int
+do_test (void)
+{
+ atexit (remove_shm);
+
+ pgsz = sysconf (_SC_PAGESIZE);
+ if (pgsz == -1)
+ FAIL_EXIT1 ("sysconf (_SC_PAGESIZE) failed: %m");
+
+ key_t key = ftok (name, 'G');
+ if (key == -1)
+ FAIL_EXIT1 ("ftok failed: %m");
+
+ shmid = shmget (key, pgsz, IPC_CREAT | IPC_EXCL | SHM_MODE);
+ if (shmid == -1)
+ FAIL_EXIT1 ("shmget failed: %m");
+
+ struct test_shminfo tipcinfo;
+ bool tipcget = read_shm_stat (&tipcinfo);
+
+ int shmidx;
+
+ /* Note: SHM_INFO does not return a shminfo, but rather a 'struct shm_info'
+ and it is tricky to verify it since it returns system resources consumed
+ by shared memory. The shmctl implementation handles SHM_INFO as
+ IPC_INFO, so the IPC_INFO test should validate SHM_INFO as well. */
+
+ {
+ struct shminfo ipcinfo;
+ shmidx = shmctl (shmid, IPC_INFO, (struct shmid_ds *) &ipcinfo);
+ if (shmidx == -1)
+ FAIL_EXIT1 ("shmctl with IPC_INFO failed: %m");
+
+ /* We only check if /proc is mounted. */
+ if (tipcget)
+ {
+ TEST_COMPARE (ipcinfo.shmall, tipcinfo.shmall);
+ TEST_COMPARE (ipcinfo.shmmax, tipcinfo.shmmax);
+ TEST_COMPARE (ipcinfo.shmmni, tipcinfo.shmmni);
+ }
+ }
+
+ /* We check if the created shared memory shows in the global list. */
+ bool found = false;
+ for (int i = 0; i <= shmidx; i++)
+ {
+ if (check_shminfo (i, key, SHM_STAT))
+ {
+ found = true;
+ break;
+ }
+
+ /* We can't tell apart if SHM_STAT_ANY is not supported (kernel older
+ than 4.17) or if the index used is invalid. So it just check if
+ value returned from a valid call matches the created message
+ queue. */
+ check_shminfo (i, key, SHM_STAT_ANY);
+ }
+
+ if (!found)
+ FAIL_EXIT1 ("shmctl with SHM_STAT/SHM_STAT_ANY could not find the "
+ "created shared memory");
+
+ if (shmctl (shmid, IPC_RMID, NULL) == -1)
+ FAIL_EXIT1 ("shmctl failed");
+
+ return 0;
+}
+
+#include <support/test-driver.c>
--
2.25.1
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