#include "reiserfs.h"
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/xattr.h>
#include <linux/slab.h>
#include "xattr.h"
#include <linux/security.h>
#include <linux/uaccess.h>

static int
security_get(const struct xattr_handler *handler, struct dentry *unused,
	     struct inode *inode, const char *name, void *buffer, size_t size)
{
	if (IS_PRIVATE(inode))
		return -EPERM;

	return reiserfs_xattr_get(inode, xattr_full_name(handler, name),
				  buffer, size);
}

static int
security_set(const struct xattr_handler *handler, struct dentry *unused,
	     struct inode *inode, const char *name, const void *buffer,
	     size_t size, int flags)
{
	if (IS_PRIVATE(inode))
		return -EPERM;

	return reiserfs_xattr_set(inode,
				  xattr_full_name(handler, name),
				  buffer, size, flags);
}

static bool security_list(struct dentry *dentry)
{
	return !IS_PRIVATE(d_inode(dentry));
}

/* Initializes the security context for a new inode and returns the number
 * of blocks needed for the transaction. If successful, reiserfs_security
 * must be released using reiserfs_security_free when the caller is done. */
int reiserfs_security_init(struct inode *dir, struct inode *inode,
			   const struct qstr *qstr,
			   struct reiserfs_security_handle *sec)
{
	int blocks = 0;
	int error;

	sec->name = NULL;

	/* Don't add selinux attributes on xattrs - they'll never get used */
	if (IS_PRIVATE(dir))
		return 0;

	error = security_old_inode_init_security(inode, dir, qstr, &sec->name,
						 &sec->value, &sec->length);
	if (error) {
		if (error == -EOPNOTSUPP)
			error = 0;

		sec->name = NULL;
		sec->value = NULL;
		sec->length = 0;
		return error;
	}

	if (sec->length && reiserfs_xattrs_initialized(inode->i_sb)) {
		blocks = reiserfs_xattr_jcreate_nblocks(inode) +
			 reiserfs_xattr_nblocks(inode, sec->length);
		/* We don't want to count the directories twice if we have
		 * a default ACL. */
		REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
	}
	return blocks;
}

int reiserfs_security_write(struct reiserfs_transaction_handle *th,
			    struct inode *inode,
			    struct reiserfs_security_handle *sec)
{
	int error;
	if (strlen(sec->name) < sizeof(XATTR_SECURITY_PREFIX))
		return -EINVAL;

	error = reiserfs_xattr_set_handle(th, inode, sec->name, sec->value,
					  sec->length, XATTR_CREATE);
	if (error == -ENODATA || error == -EOPNOTSUPP)
		error = 0;

	return error;
}

void reiserfs_security_free(struct reiserfs_security_handle *sec)
{
	kfree(sec->name);
	kfree(sec->value);
	sec->name = NULL;
	sec->value = NULL;
}

const struct xattr_handler reiserfs_xattr_security_handler = {
	.prefix = XATTR_SECURITY_PREFIX,
	.get = security_get,
	.set = security_set,
	.list = security_list,
};
inux/net-next.git/commit/?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>drivers</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>usb</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/misc?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>misc</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/misc/rio500_usb.h?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>rio500_usb.h</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='c8f325a59cfc718d13a50fbc746ed9b415c25e92'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></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>Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;</td><td class='right'>2017-02-01 17:45:02 +0000</td></tr>
<tr><th>committer</th><td>Ingo Molnar &lt;mingo@kernel.org&gt;</td><td class='right'>2017-02-01 21:17:49 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/misc/rio500_usb.h?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>c8f325a59cfc718d13a50fbc746ed9b415c25e92</a> (<a href='/cgit.cgi/linux/net-next.git/patch/drivers/usb/misc/rio500_usb.h?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>d53fbdac9d0781e39a13b2ac6b2bd258cf3b4140</a> /<a href='/cgit.cgi/linux/net-next.git/tree/drivers/usb/misc/rio500_usb.h?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>drivers/usb/misc/rio500_usb.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/misc/rio500_usb.h?id=bf29bddf0417a4783da3b24e8c9e017ac649326f'>bf29bddf0417a4783da3b24e8c9e017ac649326f</a> (<a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/misc/rio500_usb.h?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92&amp;id2=bf29bddf0417a4783da3b24e8c9e017ac649326f'>diff</a>)</td></tr></table>
<div class='commit-subject'>efi/fdt: Avoid FDT manipulation after ExitBootServices()</div><div class='commit-msg'>Some AArch64 UEFI implementations disable the MMU in ExitBootServices(),
after which unaligned accesses to RAM are no longer supported.

Commit:

  abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel")

fixed an issue in the memory map handling of the stub FDT code, but
inadvertently created an issue with such firmware, by moving some
of the FDT manipulation to after the invocation of ExitBootServices().

Given that the stub's libfdt implementation uses the ordinary, accelerated
string functions, which rely on hardware handling of unaligned accesses,
manipulating the FDT with the MMU off may result in alignment faults.

So fix the situation by moving the update_fdt_memmap() call into the
callback function invoked by efi_exit_boot_services() right before it
calls the ExitBootServices() UEFI service (which is arguably a better
place for it anyway)

Note that disabling the MMU in ExitBootServices() is not compliant with
the UEFI spec, and carries great risk due to the fact that switching from
cached to uncached memory accesses halfway through compiler generated code
(i.e., involving a stack) can never be done in a way that is architecturally
safe.

Fixes: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel")
Signed-off-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Tested-by: Riku Voipio &lt;riku.voipio@linaro.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Cc: mark.rutland@arm.com
Cc: linux-efi@vger.kernel.org
Cc: matt@codeblueprint.co.uk
Cc: leif.lindholm@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1485971102-23330-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>Diffstat</a> (limited to 'drivers/usb/misc/rio500_usb.h')</div><table summary='diffstat' class='diffstat'>