/* * iovec manipulation routines. * * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Fixes: * Andrew Lunn : Errors in iovec copying. * Pedro Roque : Added memcpy_fromiovecend and * csum_..._fromiovecend. * Andi Kleen : fixed error handling for 2.1 * Alexey Kuznetsov: 2.1 optimisations * Andi Kleen : Fix csum*fromiovecend for IPv6. */ #include <linux/errno.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/net.h> #include <linux/in6.h> #include <asm/uaccess.h> #include <asm/byteorder.h> #include <net/checksum.h> #include <net/sock.h> /* * Verify iovec. The caller must ensure that the iovec is big enough * to hold the message iovec. * * Save time not doing access_ok. copy_*_user will make this work * in any case. */ int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr *address, int mode) { int size, err, ct; if (m->msg_namelen) { if (mode == VERIFY_READ) { err = move_addr_to_kernel(m->msg_name, m->msg_namelen, address); if (err < 0) return err; } m->msg_name = address; } else { m->msg_name = NULL; } size = m->msg_iovlen * sizeof(struct iovec); if (copy_from_user(iov, m->msg_iov, size)) return -EFAULT; m->msg_iov = iov; err = 0; for (ct = 0; ct < m->msg_iovlen; ct++) { err += iov[ct].iov_len; /* * Goal is not to verify user data, but to prevent returning * negative value, which is interpreted as errno. * Overflow is still possible, but it is harmless. */ if (err < 0) return -EMSGSIZE; } return err; } /* * Copy kernel to iovec. Returns -EFAULT on error. * * Note: this modifies the original iovec. */ int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len) { while (len > 0) { if (iov->iov_len) { int copy = min_t(unsigned int, iov->iov_len, len); if (copy_to_user(iov->iov_base, kdata, copy)) return -EFAULT; kdata += copy; len -= copy; iov->iov_len -= copy; iov->iov_base += copy; } iov++; } return 0; } /* * Copy kernel to iovec. Returns -EFAULT on error. */ int memcpy_toiovecend(const struct iovec *iov, unsigned char *kdata, int offset, int len) { int copy; for (; len > 0; ++iov) { /* Skip over the finished iovecs */ if (unlikely(offset >= iov->iov_len)) { offset -= iov->iov_len; continue; } copy = min_t(unsigned int, iov->iov_len - offset, len); if (copy_to_user(iov->iov_base + offset, kdata, copy)) return -EFAULT; offset = 0; kdata += copy; len -= copy; } return 0; } /* * Copy iovec to kernel. Returns -EFAULT on error. * * Note: this modifies the original iovec. */ int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len) { while (len > 0) { if (iov->iov_len) { int copy = min_t(unsigned int, len, iov->iov_len); if (copy_from_user(kdata, iov->iov_base, copy)) return -EFAULT; len -= copy; kdata += copy; iov->iov_base += copy; iov->iov_len -= copy; } iov++; } return 0; } /* * Copy iovec from kernel. Returns -EFAULT on error. */ int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov, int offset, int len) { /* Skip over the finished iovecs */ while (offset >= iov->iov_len) { offset -= iov->iov_len; iov++; } while (len > 0) { u8 __user *base = iov->iov_base + offset; int copy = min_t(unsigned int, len, iov->iov_len - offset); offset = 0; if (copy_from_user(kdata, base, copy)) return -EFAULT; len -= copy; kdata += copy; iov++; } return 0; } /* * And now for the all-in-one: copy and checksum from a user iovec * directly to a datagram * Calls to csum_partial but the last must be in 32 bit chunks * * ip_build_xmit must ensure that when fragmenting only the last * call to this function will be unaligned also. */ int csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov, int offset, unsigned int len, __wsum *csump) { __wsum csum = *csump; int partial_cnt = 0, err = 0; /* Skip over the finished iovecs */ while (offset >= iov->iov_len) { offset -= iov->iov_len; iov++; } while (len > 0) { u8 __user *base = iov->iov_base + offset; int copy = min_t(unsigned int, len, iov->iov_len - offset); offset = 0; /* There is a remnant from previous iov. */ if (partial_cnt) { int par_len = 4 - partial_cnt; /* iov component is too short ... */ if (par_len > copy) { if (copy_from_user(kdata, base, copy)) goto out_fault; kdata += copy; base += copy; partial_cnt += copy; len -= copy; iov++; if (len) continue; *csump = csum_partial(kdata - partial_cnt, partial_cnt, csum); goto out; } if (copy_from_user(kdata, base, par_len)) goto out_fault; csum = csum_partial(kdata - partial_cnt, 4, csum); kdata += par_len; base += par_len; copy -= par_len; len -= par_len; partial_cnt = 0; } if (len > copy) { partial_cnt = copy % 4; if (partial_cnt) { copy -= partial_cnt; if (copy_from_user(kdata + copy, base + copy, partial_cnt)) goto out_fault; } } if (copy) { csum = csum_and_copy_from_user(base, kdata, copy, csum, &err); if (err) goto out; } len -= copy + partial_cnt; kdata += copy + partial_cnt; iov++; } *csump = csum; out: return err; out_fault: err = -EFAULT; goto out; } EXPORT_SYMBOL(csum_partial_copy_fromiovecend); EXPORT_SYMBOL(memcpy_fromiovec); EXPORT_SYMBOL(memcpy_fromiovecend); EXPORT_SYMBOL(memcpy_toiovec); EXPORT_SYMBOL(memcpy_toiovecend);