/*
 * Access kernel memory without faulting.
 */
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/uaccess.h>

/**
 * probe_kernel_read(): safely attempt to read from a location
 * @dst: pointer to the buffer that shall take the data
 * @src: address to read from
 * @size: size of the data chunk
 *
 * Safely read from address @src to the buffer at @dst.  If a kernel fault
 * happens, handle that and return -EFAULT.
 *
 * We ensure that the copy_from_user is executed in atomic context so that
 * do_page_fault() doesn't attempt to take mmap_sem.  This makes
 * probe_kernel_read() suitable for use within regions where the caller
 * already holds mmap_sem, or other locks which nest inside mmap_sem.
 */

long __weak probe_kernel_read(void *dst, const void *src, size_t size)
    __attribute__((alias("__probe_kernel_read")));

long __probe_kernel_read(void *dst, const void *src, size_t size)
{
	long ret;
	mm_segment_t old_fs = get_fs();

	set_fs(KERNEL_DS);
	pagefault_disable();
	ret = __copy_from_user_inatomic(dst,
			(__force const void __user *)src, size);
	pagefault_enable();
	set_fs(old_fs);

	return ret ? -EFAULT : 0;
}
EXPORT_SYMBOL_GPL(probe_kernel_read);

/**
 * probe_kernel_write(): safely attempt to write to a location
 * @dst: address to write to
 * @src: pointer to the data that shall be written
 * @size: size of the data chunk
 *
 * Safely write to address @dst from the buffer at @src.  If a kernel fault
 * happens, handle that and return -EFAULT.
 */
long __weak probe_kernel_write(void *dst, const void *src, size_t size)
    __attribute__((alias("__probe_kernel_write")));

long __probe_kernel_write(void *dst, const void *src, size_t size)
{
	long ret;
	mm_segment_t old_fs = get_fs();

	set_fs(KERNEL_DS);
	pagefault_disable();
	ret = __copy_to_user_inatomic((__force void __user *)dst, src, size);
	pagefault_enable();
	set_fs(old_fs);

	return ret ? -EFAULT : 0;
}
EXPORT_SYMBOL_GPL(probe_kernel_write);

/**
 * strncpy_from_unsafe: - Copy a NUL terminated string from unsafe address.
 * @dst:   Destination address, in kernel space.  This buffer must be at
 *         least @count bytes long.
 * @src:   Unsafe address.
 * @count: Maximum number of bytes to copy, including the trailing NUL.
 *
 * Copies a NUL-terminated string from unsafe address to kernel buffer.
 *
 * On success, returns the length of the string INCLUDING the trailing NUL.
 *
 * If access fails, returns -EFAULT (some data may have been copied
 * and the trailing NUL added).
 *
 * If @count is smaller than the length of the string, copies @count-1 bytes,
 * sets the last byte of @dst buffer to NUL and returns @count.
 */
long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count)
{
	mm_segment_t old_fs = get_fs();
	const void *src = unsafe_addr;
	long ret;

	if (unlikely(count <= 0))
		return 0;

	set_fs(KERNEL_DS);
	pagefault_disable();

	do {
		ret = __get_user(*dst++, (const char __user __force *)src++);
	} while (dst[-1] && ret == 0 && src - unsafe_addr < count);

	dst[-1] = '\0';
	pagefault_enable();
	set_fs(old_fs);

	return ret ? -EFAULT : src - unsafe_addr;
}
wmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
<tr><td><span title='2017-02-03 11:05:23 -0500'>2017-02-03</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include/uapi?id=013e8167899d389075160412a8c0c5e0581e1f13'>ipv6: sr: remove cleanup flag and fix HMAC computation</a></td><td>David Lebrun</td><td>1</td><td><span class='deletions'>-6</span>/<span class='insertions'>+3</span></td></tr>
 href='/cgit.cgi/linux/net-next.git/log/net/ieee802154/header_ops.c?h=nds-private-remove&amp;id=189addce85330208bea50ea7f1483b58822e93cf&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
on></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2016-10-15 12:17:50 -0700</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2016-10-15 12:17:50 -0700</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/core/Makefile?id=1001354ca34179f3db924eb66672442a173147dc'>1001354ca34179f3db924eb66672442a173147dc</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/core/Makefile?id=1001354ca34179f3db924eb66672442a173147dc'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=1001354ca34179f3db924eb66672442a173147dc'>000de57080b6bece6d336bc8c9d377a59b8129c9</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/core/Makefile?id=1001354ca34179f3db924eb66672442a173147dc'>net/core/Makefile</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/core/Makefile?id=df34d04a6f09ba41037e58c3df6d6fbed0ffcde9'>df34d04a6f09ba41037e58c3df6d6fbed0ffcde9</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/core/Makefile?id=1001354ca34179f3db924eb66672442a173147dc&amp;id2=df34d04a6f09ba41037e58c3df6d6fbed0ffcde9'>diff</a>)</td></tr></table>
<div class='commit-subject'>Linux 4.9-rc1</div><div class='commit-msg'></div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=1001354ca34179f3db924eb66672442a173147dc'>Diffstat</a> (limited to 'net/core/Makefile')</div><table summary='diffstat' class='diffstat'>