diff options
Diffstat (limited to 'fs/fcntl.c')
| -rw-r--r-- | fs/fcntl.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c index de1b16bb6a29..f4e7267d117f 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -23,6 +23,7 @@ #include <linux/pid_namespace.h> #include <linux/user_namespace.h> #include <linux/shmem_fs.h> +#include <linux/compat.h> #include <asm/poll.h> #include <asm/siginfo.h> @@ -420,6 +421,162 @@ out: } #endif +#ifdef CONFIG_COMPAT +static int get_compat_flock(struct flock *kfl, struct compat_flock __user *ufl) +{ + if (!access_ok(VERIFY_READ, ufl, sizeof(*ufl)) || + __get_user(kfl->l_type, &ufl->l_type) || + __get_user(kfl->l_whence, &ufl->l_whence) || + __get_user(kfl->l_start, &ufl->l_start) || + __get_user(kfl->l_len, &ufl->l_len) || + __get_user(kfl->l_pid, &ufl->l_pid)) + return -EFAULT; + return 0; +} + +static int put_compat_flock(struct flock *kfl, struct compat_flock __user *ufl) +{ + if (!access_ok(VERIFY_WRITE, ufl, sizeof(*ufl)) || + __put_user(kfl->l_type, &ufl->l_type) || + __put_user(kfl->l_whence, &ufl->l_whence) || + __put_user(kfl->l_start, &ufl->l_start) || + __put_user(kfl->l_len, &ufl->l_len) || + __put_user(kfl->l_pid, &ufl->l_pid)) + return -EFAULT; + return 0; +} + +#ifndef HAVE_ARCH_GET_COMPAT_FLOCK64 +static int get_compat_flock64(struct flock *kfl, struct compat_flock64 __user *ufl) +{ + if (!access_ok(VERIFY_READ, ufl, sizeof(*ufl)) || + __get_user(kfl->l_type, &ufl->l_type) || + __get_user(kfl->l_whence, &ufl->l_whence) || + __get_user(kfl->l_start, &ufl->l_start) || + __get_user(kfl->l_len, &ufl->l_len) || + __get_user(kfl->l_pid, &ufl->l_pid)) + return -EFAULT; + return 0; +} +#endif + +#ifndef HAVE_ARCH_PUT_COMPAT_FLOCK64 +static int put_compat_flock64(struct flock *kfl, struct compat_flock64 __user *ufl) +{ + if (!access_ok(VERIFY_WRITE, ufl, sizeof(*ufl)) || + __put_user(kfl->l_type, &ufl->l_type) || + __put_user(kfl->l_whence, &ufl->l_whence) || + __put_user(kfl->l_start, &ufl->l_start) || + __put_user(kfl->l_len, &ufl->l_len) || + __put_user(kfl->l_pid, &ufl->l_pid)) + return -EFAULT; + return 0; +} +#endif + +static unsigned int +convert_fcntl_cmd(unsigned int cmd) +{ + switch (cmd) { + case F_GETLK64: + return F_GETLK; + case F_SETLK64: + return F_SETLK; + case F_SETLKW64: + return F_SETLKW; + } + + return cmd; +} + +COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, + compat_ulong_t, arg) +{ + mm_segment_t old_fs; + struct flock f; + long ret; + unsigned int conv_cmd; + + switch (cmd) { + case F_GETLK: + case F_SETLK: + case F_SETLKW: + ret = get_compat_flock(&f, compat_ptr(arg)); + if (ret != 0) + break; + old_fs = get_fs(); + set_fs(KERNEL_DS); + ret = sys_fcntl(fd, cmd, (unsigned long)&f); + set_fs(old_fs); + if (cmd == F_GETLK && ret == 0) { + /* GETLK was successful and we need to return the data... + * but it needs to fit in the compat structure. + * l_start shouldn't be too big, unless the original + * start + end is greater than COMPAT_OFF_T_MAX, in which + * case the app was asking for trouble, so we return + * -EOVERFLOW in that case. + * l_len could be too big, in which case we just truncate it, + * and only allow the app to see that part of the conflicting + * lock that might make sense to it anyway + */ + + if (f.l_start > COMPAT_OFF_T_MAX) + ret = -EOVERFLOW; + if (f.l_len > COMPAT_OFF_T_MAX) + f.l_len = COMPAT_OFF_T_MAX; + if (ret == 0) + ret = put_compat_flock(&f, compat_ptr(arg)); + } + break; + + case F_GETLK64: + case F_SETLK64: + case F_SETLKW64: + case F_OFD_GETLK: + case F_OFD_SETLK: + case F_OFD_SETLKW: + ret = get_compat_flock64(&f, compat_ptr(arg)); + if (ret != 0) + break; + old_fs = get_fs(); + set_fs(KERNEL_DS); + conv_cmd = convert_fcntl_cmd(cmd); + ret = sys_fcntl(fd, conv_cmd, (unsigned long)&f); + set_fs(old_fs); + if ((conv_cmd == F_GETLK || conv_cmd == F_OFD_GETLK) && ret == 0) { + /* need to return lock information - see above for commentary */ + if (f.l_start > COMPAT_LOFF_T_MAX) + ret = -EOVERFLOW; + if (f.l_len > COMPAT_LOFF_T_MAX) + f.l_len = COMPAT_LOFF_T_MAX; + if (ret == 0) + ret = put_compat_flock64(&f, compat_ptr(arg)); + } + break; + + default: + ret = sys_fcntl(fd, cmd, arg); + break; + } + return ret; +} + +COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, + compat_ulong_t, arg) +{ + switch (cmd) { + case F_GETLK64: + case F_SETLK64: + case F_SETLKW64: + case F_OFD_GETLK: + case F_OFD_SETLK: + case F_OFD_SETLKW: + return -EINVAL; + } + return compat_sys_fcntl64(fd, cmd, arg); +} +#endif + /* Table to convert sigio signal codes into poll band bitmaps */ static const long band_table[NSIGPOLL] = { |