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06ebb06d49
Check for cases when the caller requests 0 bytes instead of running off and dereferencing potentially invalid iovecs. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
112 lines
2.2 KiB
C
112 lines
2.2 KiB
C
#include <linux/uaccess.h>
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#include <linux/export.h>
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#include <linux/uio.h>
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/*
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* Copy iovec to kernel. Returns -EFAULT on error.
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*
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* Note: this modifies the original iovec.
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*/
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int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len)
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{
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while (len > 0) {
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if (iov->iov_len) {
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int copy = min_t(unsigned int, len, iov->iov_len);
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if (copy_from_user(kdata, iov->iov_base, copy))
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return -EFAULT;
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len -= copy;
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kdata += copy;
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iov->iov_base += copy;
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iov->iov_len -= copy;
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}
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iov++;
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}
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return 0;
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}
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EXPORT_SYMBOL(memcpy_fromiovec);
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/*
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* Copy kernel to iovec. Returns -EFAULT on error.
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*
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* Note: this modifies the original iovec.
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*/
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int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len)
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{
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while (len > 0) {
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if (iov->iov_len) {
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int copy = min_t(unsigned int, iov->iov_len, len);
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if (copy_to_user(iov->iov_base, kdata, copy))
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return -EFAULT;
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kdata += copy;
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len -= copy;
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iov->iov_len -= copy;
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iov->iov_base += copy;
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}
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iov++;
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}
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return 0;
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}
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EXPORT_SYMBOL(memcpy_toiovec);
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/*
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* Copy kernel to iovec. Returns -EFAULT on error.
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*/
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int memcpy_toiovecend(const struct iovec *iov, unsigned char *kdata,
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int offset, int len)
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{
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int copy;
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for (; len > 0; ++iov) {
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/* Skip over the finished iovecs */
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if (unlikely(offset >= iov->iov_len)) {
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offset -= iov->iov_len;
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continue;
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}
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copy = min_t(unsigned int, iov->iov_len - offset, len);
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if (copy_to_user(iov->iov_base + offset, kdata, copy))
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return -EFAULT;
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offset = 0;
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kdata += copy;
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len -= copy;
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}
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return 0;
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}
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EXPORT_SYMBOL(memcpy_toiovecend);
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/*
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* Copy iovec to kernel. Returns -EFAULT on error.
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*/
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int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
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int offset, int len)
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{
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/* No data? Done! */
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if (len == 0)
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return 0;
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/* Skip over the finished iovecs */
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while (offset >= iov->iov_len) {
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offset -= iov->iov_len;
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iov++;
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}
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while (len > 0) {
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u8 __user *base = iov->iov_base + offset;
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int copy = min_t(unsigned int, len, iov->iov_len - offset);
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offset = 0;
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if (copy_from_user(kdata, base, copy))
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return -EFAULT;
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len -= copy;
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kdata += copy;
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iov++;
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}
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return 0;
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}
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EXPORT_SYMBOL(memcpy_fromiovecend);
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