diff options
| -rw-r--r-- | fs/compat.c | 130 | ||||
| -rw-r--r-- | include/linux/compat.h | 4 |
2 files changed, 81 insertions, 53 deletions
diff --git a/fs/compat.c b/fs/compat.c index 05448730f840..7b4aabb3bb36 100644 --- a/fs/compat.c +++ b/fs/compat.c @@ -568,6 +568,79 @@ out: return ret; } +/* A write operation does a read from user space and vice versa */ +#define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ) + +ssize_t compat_rw_copy_check_uvector(int type, + const struct compat_iovec __user *uvector, unsigned long nr_segs, + unsigned long fast_segs, struct iovec *fast_pointer, + struct iovec **ret_pointer) +{ + compat_ssize_t tot_len; + struct iovec *iov = *ret_pointer = fast_pointer; + ssize_t ret = 0; + int seg; + + /* + * SuS says "The readv() function *may* fail if the iovcnt argument + * was less than or equal to 0, or greater than {IOV_MAX}. Linux has + * traditionally returned zero for zero segments, so... + */ + if (nr_segs == 0) + goto out; + + ret = -EINVAL; + if (nr_segs > UIO_MAXIOV || nr_segs < 0) + goto out; + if (nr_segs > fast_segs) { + ret = -ENOMEM; + iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL); + if (iov == NULL) { + *ret_pointer = fast_pointer; + goto out; + } + } + *ret_pointer = iov; + + /* + * Single unix specification: + * We should -EINVAL if an element length is not >= 0 and fitting an + * ssize_t. The total length is fitting an ssize_t + * + * Be careful here because iov_len is a size_t not an ssize_t + */ + tot_len = 0; + ret = -EINVAL; + for (seg = 0; seg < nr_segs; seg++) { + compat_ssize_t tmp = tot_len; + compat_uptr_t buf; + compat_ssize_t len; + + if (__get_user(len, &uvector->iov_len) || + __get_user(buf, &uvector->iov_base)) { + ret = -EFAULT; + goto out; + } + if (len < 0) /* size_t not fitting in compat_ssize_t .. */ + goto out; + tot_len += len; + if (tot_len < tmp) /* maths overflow on the compat_ssize_t */ + goto out; + if (!access_ok(vrfy_dir(type), buf, len)) { + ret = -EFAULT; + goto out; + } + iov->iov_base = compat_ptr(buf); + iov->iov_len = (compat_size_t) len; + uvector++; + iov++; + } + ret = tot_len; + +out: + return ret; +} + static inline long copy_iocb(long nr, u32 __user *ptr32, struct iocb __user * __user *ptr64) { @@ -1077,70 +1150,21 @@ static ssize_t compat_do_readv_writev(int type, struct file *file, { compat_ssize_t tot_len; struct iovec iovstack[UIO_FASTIOV]; - struct iovec *iov=iovstack, *vector; + struct iovec *iov; ssize_t ret; - int seg; io_fn_t fn; iov_fn_t fnv; - /* - * SuS says "The readv() function *may* fail if the iovcnt argument - * was less than or equal to 0, or greater than {IOV_MAX}. Linux has - * traditionally returned zero for zero segments, so... - */ - ret = 0; - if (nr_segs == 0) - goto out; - - /* - * First get the "struct iovec" from user memory and - * verify all the pointers - */ ret = -EINVAL; - if ((nr_segs > UIO_MAXIOV) || (nr_segs <= 0)) - goto out; if (!file->f_op) goto out; - if (nr_segs > UIO_FASTIOV) { - ret = -ENOMEM; - iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL); - if (!iov) - goto out; - } + ret = -EFAULT; if (!access_ok(VERIFY_READ, uvector, nr_segs*sizeof(*uvector))) goto out; - /* - * Single unix specification: - * We should -EINVAL if an element length is not >= 0 and fitting an - * ssize_t. The total length is fitting an ssize_t - * - * Be careful here because iov_len is a size_t not an ssize_t - */ - tot_len = 0; - vector = iov; - ret = -EINVAL; - for (seg = 0 ; seg < nr_segs; seg++) { - compat_ssize_t tmp = tot_len; - compat_ssize_t len; - compat_uptr_t buf; - - if (__get_user(len, &uvector->iov_len) || - __get_user(buf, &uvector->iov_base)) { - ret = -EFAULT; - goto out; - } - if (len < 0) /* size_t not fitting an compat_ssize_t .. */ - goto out; - tot_len += len; - if (tot_len < tmp) /* maths overflow on the compat_ssize_t */ - goto out; - vector->iov_base = compat_ptr(buf); - vector->iov_len = (compat_size_t) len; - uvector++; - vector++; - } + tot_len = compat_rw_copy_check_uvector(type, uvector, nr_segs, + UIO_FASTIOV, iovstack, &iov); if (tot_len == 0) { ret = 0; goto out; diff --git a/include/linux/compat.h b/include/linux/compat.h index 717c691ecd8e..168f7daa7bde 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -356,5 +356,9 @@ asmlinkage long compat_sys_newfstatat(unsigned int dfd, char __user * filename, asmlinkage long compat_sys_openat(unsigned int dfd, const char __user *filename, int flags, int mode); +extern ssize_t compat_rw_copy_check_uvector(int type, + const struct compat_iovec __user *uvector, unsigned long nr_segs, + unsigned long fast_segs, struct iovec *fast_pointer, + struct iovec **ret_pointer); #endif /* CONFIG_COMPAT */ #endif /* _LINUX_COMPAT_H */ |