diff options
| -rw-r--r-- | Documentation/feature-removal-schedule.txt | 35 | ||||
| -rw-r--r-- | kernel/sysctl.c | 64 |
2 files changed, 76 insertions, 23 deletions
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 280ec06573e6..5b25162cd9a4 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -82,6 +82,41 @@ Who: Dominik Brodowski <linux@brodo.de> --------------------------- +What: sys_sysctl +When: September 2010 +Option: CONFIG_SYSCTL_SYSCALL +Why: The same information is available in a more convenient from + /proc/sys, and none of the sysctl variables appear to be + important performance wise. + + Binary sysctls are a long standing source of subtle kernel + bugs and security issues. + + When I looked several months ago all I could find after + searching several distributions were 5 user space programs and + glibc (which falls back to /proc/sys) using this syscall. + + The man page for sysctl(2) documents it as unusable for user + space programs. + + sysctl(2) is not generally ABI compatible to a 32bit user + space application on a 64bit and a 32bit kernel. + + For the last several months the policy has been no new binary + sysctls and no one has put forward an argument to use them. + + Binary sysctls issues seem to keep happening appearing so + properly deprecating them (with a warning to user space) and a + 2 year grace warning period will mean eventually we can kill + them and end the pain. + + In the mean time individual binary sysctls can be dealt with + in a piecewise fashion. + +Who: Eric Biederman <ebiederm@xmission.com> + +--------------------------- + What: a.out interpreter support for ELF executables When: 2.6.25 Files: fs/binfmt_elf.c diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 62e53a0de4a3..c25e67e19af7 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -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 :-) |