diff options
Diffstat (limited to 'net/core/iovec.c')
| -rw-r--r-- | net/core/iovec.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/net/core/iovec.c b/net/core/iovec.c new file mode 100644 index 00000000000..d57ace949ab --- /dev/null +++ b/net/core/iovec.c @@ -0,0 +1,239 @@ +/* + * 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/sched.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/slab.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 verify_area. copy_*_user will make this work + * in any case. + */ + +int verify_iovec(struct msghdr *m, struct iovec *iov, char *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 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; +} + +/* + * For use with ip_build_xmit + */ +int memcpy_fromiovecend(unsigned char *kdata, 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, int *csump) +{ + int 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); |