This uses compat_alloc_userspace to remove the various hacks to allow do_sysctl to write to throuh oldlenp. The rest of our mature compat syscall helper facitilies are used as well to ensure we have a nice clean maintainable compat syscall that can be used on all architectures. The motiviation for a generic compat sysctl (besides the obvious hack removal) is to reduce the number of compat sysctl defintions out there so I can refactor the binary sysctl implementation. ppc already used the name compat_sys_sysctl so I remove the ppcs version here.
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| @@ -176,3 +176,53 @@ SYSCALL_DEFINE1(sysctl, struct __sysctl_args __user *, args) · 175 unmodified lines | |||
| 176 | 176 | ||
| 177 | return error; | 177 | return error; |
| 178 | } | 178 | } |
| 179 | |||
| 180 | #ifdef CONFIG_COMPAT | ||
| 181 | #include <asm/compat.h> | ||
| 182 | |||
| 183 | struct compat_sysctl_args { | ||
| 184 | compat_uptr_t name; | ||
| 185 | int nlen; | ||
| 186 | compat_uptr_t oldval; | ||
| 187 | compat_uptr_t oldlenp; | ||
| 188 | compat_uptr_t newval; | ||
| 189 | compat_size_t newlen; | ||
| 190 | compat_ulong_t __unused[4]; | ||
| 191 | }; | ||
| 192 | |||
| 193 | asmlinkage long compat_sys_sysctl(struct compat_sysctl_args __user *args) | ||
| 194 | { | ||
| 195 | struct compat_sysctl_args tmp; | ||
| 196 | compat_size_t __user *compat_oldlenp; | ||
| 197 | size_t __user *oldlenp = NULL; | ||
| 198 | size_t oldlen = 0; | ||
| 199 | ssize_t result; | ||
| 200 | |||
| 201 | if (copy_from_user(&tmp, args, sizeof(tmp))) | ||
| 202 | return -EFAULT; | ||
| 203 | |||
| 204 | compat_oldlenp = compat_ptr(tmp.oldlenp); | ||
| 205 | if (compat_oldlenp) { | ||
| 206 | oldlenp = compat_alloc_user_space(sizeof(*compat_oldlenp)); | ||
| 207 | |||
| 208 | if (get_user(oldlen, compat_oldlenp) || | ||
| 209 | put_user(oldlen, oldlenp)) | ||
| 210 | return -EFAULT; | ||
| 211 | } | ||
| 212 | |||
| 213 | lock_kernel(); | ||
| 214 | result = do_sysctl(compat_ptr(tmp.name), tmp.nlen, | ||
| 215 | compat_ptr(tmp.oldval), oldlenp, | ||
| 216 | compat_ptr(tmp.newval), tmp.newlen); | ||
| 217 | unlock_kernel(); | ||
| 218 | |||
| 219 | if (oldlenp && !result) { | ||
| 220 | if (get_user(oldlen, oldlenp) || | ||
| 221 | put_user(oldlen, compat_oldlenp)) | ||
| 222 | return -EFAULT; | ||
| 223 | } | ||
| 224 | |||
| 225 | return result; | ||
| 226 | } | ||
| 227 | |||
| 228 | #endif /* CONFIG_COMPAT */ | ||