diff options
| -rw-r--r-- | fs/compat.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/fs/compat.c b/fs/compat.c index 55ac0324aaf1..271b75d1597f 100644 --- a/fs/compat.c +++ b/fs/compat.c @@ -494,9 +494,21 @@ asmlinkage long compat_sys_fcntl64(unsigned int fd, unsigned int cmd, ret = sys_fcntl(fd, cmd, (unsigned long)&f); set_fs(old_fs); if (cmd == F_GETLK && ret == 0) { - if ((f.l_start >= COMPAT_OFF_T_MAX) || - ((f.l_start + f.l_len) > COMPAT_OFF_T_MAX)) + /* GETLK was successfule 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)); } @@ -515,9 +527,11 @@ asmlinkage long compat_sys_fcntl64(unsigned int fd, unsigned int cmd, (unsigned long)&f); set_fs(old_fs); if (cmd == F_GETLK64 && ret == 0) { - if ((f.l_start >= COMPAT_LOFF_T_MAX) || - ((f.l_start + f.l_len) > COMPAT_LOFF_T_MAX)) + /* 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)); } |