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From: Florian Weimer <fw@sourceware.org>
To: glibc-cvs@sourceware.org
Subject: [glibc] Linux: Support __IPC_64 in sysvctl *ctl command arguments (bug 29771)
Date: Thu, 10 Nov 2022 13:23:26 +0000 (GMT) [thread overview]
Message-ID: <20221110132326.E59C33858CDA@sourceware.org> (raw)
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=22a46dee24351fd5f4f188ad80554cad79c82524
commit 22a46dee24351fd5f4f188ad80554cad79c82524
Author: Florian Weimer <fweimer@redhat.com>
Date: Tue Nov 8 14:15:02 2022 +0100
Linux: Support __IPC_64 in sysvctl *ctl command arguments (bug 29771)
Old applications pass __IPC_64 as part of the command argument because
old glibc did not check for unknown commands, and passed through the
arguments directly to the kernel, without adding __IPC_64.
Applications need to continue doing that for old glibc compatibility,
so this commit enables this approach in current glibc.
For msgctl and shmctl, if no translation is required, make
direct system calls, as we did before the time64 changes. If
translation is required, mask __IPC_64 from the command argument.
For semctl, the union-in-vararg argument handling means that
translation is needed on all architectures.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diff:
---
sysdeps/unix/sysv/linux/ipc_priv.h | 6 ++++++
sysdeps/unix/sysv/linux/msgctl.c | 38 +++++++++++++++++++++++++-------------
sysdeps/unix/sysv/linux/semctl.c | 7 +++++++
sysdeps/unix/sysv/linux/shmctl.c | 38 +++++++++++++++++++++++++-------------
4 files changed, 63 insertions(+), 26 deletions(-)
diff --git a/sysdeps/unix/sysv/linux/ipc_priv.h b/sysdeps/unix/sysv/linux/ipc_priv.h
index 87893a6757..2f50c31a8e 100644
--- a/sysdeps/unix/sysv/linux/ipc_priv.h
+++ b/sysdeps/unix/sysv/linux/ipc_priv.h
@@ -63,4 +63,10 @@ struct __old_ipc_perm
# define __IPC_TIME64 0
#endif
+#if __IPC_TIME64 || defined __ASSUME_SYSVIPC_BROKEN_MODE_T
+# define IPC_CTL_NEED_TRANSLATION 1
+#else
+# define IPC_CTL_NEED_TRANSLATION 0
+#endif
+
#include <ipc_ops.h>
diff --git a/sysdeps/unix/sysv/linux/msgctl.c b/sysdeps/unix/sysv/linux/msgctl.c
index e824ebb095..2072205252 100644
--- a/sysdeps/unix/sysv/linux/msgctl.c
+++ b/sysdeps/unix/sysv/linux/msgctl.c
@@ -85,11 +85,19 @@ msgctl_syscall (int msqid, int cmd, msgctl_arg_t *buf)
int
__msgctl64 (int msqid, int cmd, struct __msqid64_ds *buf)
{
-#if __IPC_TIME64
+#if IPC_CTL_NEED_TRANSLATION
+# if __IPC_TIME64
struct kernel_msqid64_ds ksemid, *arg = NULL;
-#else
+# else
msgctl_arg_t *arg;
-#endif
+# endif
+
+ /* Some applications pass the __IPC_64 flag in cmd, to invoke
+ previously unsupported commands back when there was no EINVAL
+ error checking in glibc. Mask the flag for the switch statements
+ below. msgctl_syscall adds back the __IPC_64 flag for the actual
+ system call. */
+ cmd &= ~__IPC_64;
switch (cmd)
{
@@ -101,19 +109,19 @@ __msgctl64 (int msqid, int cmd, struct __msqid64_ds *buf)
case IPC_STAT:
case MSG_STAT:
case MSG_STAT_ANY:
-#if __IPC_TIME64
+# if __IPC_TIME64
if (buf != NULL)
{
msqid64_to_kmsqid64 (buf, &ksemid);
arg = &ksemid;
}
-# ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
+# ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
if (cmd == IPC_SET)
arg->msg_perm.mode *= 0x10000U;
-# endif
-#else
+# endif
+# else
arg = buf;
-#endif
+# endif
break;
case IPC_INFO:
@@ -137,21 +145,25 @@ __msgctl64 (int msqid, int cmd, struct __msqid64_ds *buf)
case IPC_STAT:
case MSG_STAT:
case MSG_STAT_ANY:
-#ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
+# ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
arg->msg_perm.mode >>= 16;
-#else
+# else
/* Old Linux kernel versions might not clear the mode padding. */
if (sizeof ((struct msqid_ds){0}.msg_perm.mode)
!= sizeof (__kernel_mode_t))
arg->msg_perm.mode &= 0xFFFF;
-#endif
+# endif
-#if __IPC_TIME64
+# if __IPC_TIME64
kmsqid64_to_msqid64 (arg, buf);
-#endif
+# endif
}
return ret;
+
+#else /* !IPC_CTL_NEED_TRANSLATION */
+ return msgctl_syscall (msqid, cmd, buf);
+#endif
}
#if __TIMESIZE != 64
libc_hidden_def (__msgctl64)
diff --git a/sysdeps/unix/sysv/linux/semctl.c b/sysdeps/unix/sysv/linux/semctl.c
index 77a8130c18..3458b018bc 100644
--- a/sysdeps/unix/sysv/linux/semctl.c
+++ b/sysdeps/unix/sysv/linux/semctl.c
@@ -140,6 +140,13 @@ __semctl64 (int semid, int semnum, int cmd, ...)
union semun64 arg64 = { 0 };
va_list ap;
+ /* Some applications pass the __IPC_64 flag in cmd, to invoke
+ previously unsupported commands back when there was no EINVAL
+ error checking in glibc. Mask the flag for the switch statements
+ below. semctl_syscall adds back the __IPC_64 flag for the actual
+ system call. */
+ cmd &= ~__IPC_64;
+
/* Get the argument only if required. */
switch (cmd)
{
diff --git a/sysdeps/unix/sysv/linux/shmctl.c b/sysdeps/unix/sysv/linux/shmctl.c
index ea38935497..f00817a6f6 100644
--- a/sysdeps/unix/sysv/linux/shmctl.c
+++ b/sysdeps/unix/sysv/linux/shmctl.c
@@ -85,11 +85,19 @@ shmctl_syscall (int shmid, int cmd, shmctl_arg_t *buf)
int
__shmctl64 (int shmid, int cmd, struct __shmid64_ds *buf)
{
-#if __IPC_TIME64
+#if IPC_CTL_NEED_TRANSLATION
+# if __IPC_TIME64
struct kernel_shmid64_ds kshmid, *arg = NULL;
-#else
+# else
shmctl_arg_t *arg;
-#endif
+# endif
+
+ /* Some applications pass the __IPC_64 flag in cmd, to invoke
+ previously unsupported commands back when there was no EINVAL
+ error checking in glibc. Mask the flag for the switch statements
+ below. shmctl_syscall adds back the __IPC_64 flag for the actual
+ system call. */
+ cmd &= ~__IPC_64;
switch (cmd)
{
@@ -103,19 +111,19 @@ __shmctl64 (int shmid, int cmd, struct __shmid64_ds *buf)
case IPC_STAT:
case SHM_STAT:
case SHM_STAT_ANY:
-#if __IPC_TIME64
+# if __IPC_TIME64
if (buf != NULL)
{
shmid64_to_kshmid64 (buf, &kshmid);
arg = &kshmid;
}
-# ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
+# ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
if (cmd == IPC_SET)
arg->shm_perm.mode *= 0x10000U;
-# endif
-#else
+# endif
+# else
arg = buf;
-#endif
+# endif
break;
case IPC_INFO:
@@ -140,21 +148,25 @@ __shmctl64 (int shmid, int cmd, struct __shmid64_ds *buf)
case IPC_STAT:
case SHM_STAT:
case SHM_STAT_ANY:
-#ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
+# ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
arg->shm_perm.mode >>= 16;
-#else
+# else
/* Old Linux kernel versions might not clear the mode padding. */
if (sizeof ((struct shmid_ds){0}.shm_perm.mode)
!= sizeof (__kernel_mode_t))
arg->shm_perm.mode &= 0xFFFF;
-#endif
+# endif
-#if __IPC_TIME64
+# if __IPC_TIME64
kshmid64_to_shmid64 (arg, buf);
-#endif
+# endif
}
return ret;
+
+#else /* !IPC_CTL_NEED_TRANSLATION */
+ return shmctl_syscall (shmid, cmd, buf);
+#endif
}
#if __TIMESIZE != 64
libc_hidden_def (__shmctl64)
reply other threads:[~2022-11-10 13:23 UTC|newest]
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