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sysctl: deprecate sys_sysctl in a user space visible fashion.

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After adding checking to register_sysctl_table and finding a whole new set
of bugs.  Missed by countless code reviews and testers I have finally lost
patience with the binary sysctl interface.

The binary sysctl interface has been sort of deprecated for years and
finding a user space program that uses the syscall is more difficult then
finding a needle in a haystack.  Problems continue to crop up, with the in
kernel implementation.  So since supporting something that no one uses is
silly, deprecate sys_sysctl with a sufficient grace period and notice that
the handful of user space applications that care can be fixed or replaced.

The /proc/sys sysctl interface that people use will continue to be
supported indefinitely.

This patch moves the tested warning about sysctls from the path where
sys_sysctl to a separate path called from both implementations of
sys_sysctl, and it adds a proper entry into
Documentation/feature-removal-schedule.

Allowing us to revisit this in a couple years time and actually kill
sys_sysctl.

[lethal@linux-sh.org: sysctl: Fix syscall disabled build]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Eric W. Biederman
2007-10-18 03:05:58 -07:00
committed by Linus Torvalds
parent 8ada720d89
commit 7058cb02dd
2 changed files with 76 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

64
kernel/sysctl.c
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@@ -55,6 +55,8 @@
#include <asm/stacktrace.h>
#endif
static int deprecated_sysctl_warning(struct __sysctl_args *args);
#if defined(CONFIG_SYSCTL)
/* External variables not in a header file. */
@@ -1347,10 +1349,15 @@ asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
if (copy_from_user(&tmp, args, sizeof(tmp)))
return -EFAULT;
error = deprecated_sysctl_warning(&tmp);
if (error)
goto out;
lock_kernel();
error = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, tmp.oldlenp,
tmp.newval, tmp.newlen);
unlock_kernel();
out:
return error;
}
#endif /* CONFIG_SYSCTL_SYSCALL */
@@ -2540,35 +2547,19 @@ int sysctl_ms_jiffies(struct ctl_table *table, int __user *name, int nlen,
asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
{
static int msg_count;
struct __sysctl_args tmp;
int name[CTL_MAXNAME];
int i;
int error;
/* Read in the sysctl name for better debug message logging */
if (copy_from_user(&tmp, args, sizeof(tmp)))
return -EFAULT;
if (tmp.nlen <= 0 || tmp.nlen >= CTL_MAXNAME)
return -ENOTDIR;
for (i = 0; i < tmp.nlen; i++)
if (get_user(name[i], tmp.name + i))
return -EFAULT;
/* Ignore accesses to kernel.version */
if ((tmp.nlen == 2) && (name[0] == CTL_KERN) && (name[1] == KERN_VERSION))
goto out;
error = deprecated_sysctl_warning(&tmp);
if (msg_count < 5) {
msg_count++;
printk(KERN_INFO
"warning: process `%s' used the removed sysctl "
"system call with ", current->comm);
for (i = 0; i < tmp.nlen; i++)
printk("%d.", name[i]);
printk("\n");
}
out:
return -ENOSYS;
/* If no error reading the parameters then just -ENOSYS ... */
if (!error)
error = -ENOSYS;
return error;
}
int sysctl_data(struct ctl_table *table, int __user *name, int nlen,
@@ -2608,6 +2599,33 @@ int sysctl_ms_jiffies(struct ctl_table *table, int __user *name, int nlen,
#endif /* CONFIG_SYSCTL_SYSCALL */
static int deprecated_sysctl_warning(struct __sysctl_args *args)
{
static int msg_count;
int name[CTL_MAXNAME];
int i;
/* Read in the sysctl name for better debug message logging */
for (i = 0; i < args->nlen; i++)
if (get_user(name[i], args->name + i))
return -EFAULT;
/* Ignore accesses to kernel.version */
if ((args->nlen == 2) && (name[0] == CTL_KERN) && (name[1] == KERN_VERSION))
return 0;
if (msg_count < 5) {
msg_count++;
printk(KERN_INFO
"warning: process `%s' used the deprecated sysctl "
"system call with ", current->comm);
for (i = 0; i < args->nlen; i++)
printk("%d.", name[i]);
printk("\n");
}
return 0;
}
/*
* No sense putting this after each symbol definition, twice,
* exception granted :-)