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sysvipc: Fix IPC_INFO and SHM_INFO handling [BZ #26636]

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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).
This commit is contained in:
Adhemerval Zanella 2020-09-29 14:51:36 -03:00
parent e11ed9d2b4
commit a49d7fd4f7
3 changed files with 204 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sysdeps/unix/sysv/linux/Makefile
View File

@ -103,7 +103,7 @@ 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

24
sysdeps/unix/sysv/linux/shmctl.c
View File

@ -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:

185
sysdeps/unix/sysv/linux/tst-sysvshm-linux.c Normal file
View File

@ -0,0 +1,185 @@
/* 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 <inttypes.h>
#include <limits.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 int shmall;
unsigned long int shmmax;
unsigned long int 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 uint64_t
read_proc_file (const char *file)
{
FILE *f = fopen (file, "r");
if (f == NULL)
FAIL_UNSUPPORTED ("/proc is not mounted or %s is not available", file);
/* Handle 32-bit binaries running on 64-bit kernels. */
uint64_t v;
int r = fscanf (f, "%" SCNu64, &v);
TEST_VERIFY_EXIT (r == 1);
fclose (f);
return v;
}
/* 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");
TEST_COMPARE (shminfo.shm_perm.__key, key);
TEST_COMPARE (shminfo.shm_perm.mode, SHM_MODE);
TEST_COMPARE (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;
{
uint64_t v = read_proc_file ("/proc/sys/kernel/shmmax");
#if LONG_MAX == INT_MAX
/* Kernel explicit clamp the value for shmmax on compat symbol (32-bit
binaries running on 64-bit kernels). */
if (v > INT_MAX)
v = INT_MAX;
#endif
tipcinfo.shmmax = v;
}
tipcinfo.shmall = read_proc_file ("/proc/sys/kernel/shmall");
tipcinfo.shmmni = read_proc_file ("/proc/sys/kernel/shmmni");
int shmidx;
/* Note: SHM_INFO does not return a shminfo, but rather a 'struct shm_info'.
It is tricky to verify its values since the syscall returns system wide
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");
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++)
{
/* 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 (check_shminfo (i, key, SHM_STAT))
{
found = true;
break;
}
}
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>