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fscrypto: move ioctl processing more fully into common code

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Multiple bugs were recently fixed in the "set encryption policy" ioctl.
To make it clear that fscrypt_process_policy() and fscrypt_get_policy()
implement ioctls and therefore their implementations must take standard
security and correctness precautions, rename them to
fscrypt_ioctl_set_policy() and fscrypt_ioctl_get_policy().  Make the
latter take in a struct file * to make it consistent with the former.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Eric Biggers
2016-11-26 19:07:49 -05:00
committed by Theodore Ts'o
parent 8048123576
commit db717d8e26
6 changed files with 37 additions and 68 deletions
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34
fs/crypto/policy.c
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@@ -93,16 +93,19 @@ static int create_encryption_context_from_policy(struct inode *inode,
return inode->i_sb->s_cop->set_context(inode, &ctx, sizeof(ctx), NULL);
}
int fscrypt_process_policy(struct file *filp,
const struct fscrypt_policy *policy)
int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
{
struct fscrypt_policy policy;
struct inode *inode = file_inode(filp);
int ret;
if (copy_from_user(&policy, arg, sizeof(policy)))
return -EFAULT;
if (!inode_owner_or_capable(inode))
return -EACCES;
if (policy->version != 0)
if (policy.version != 0)
return -EINVAL;
ret = mnt_want_write_file(filp);
@@ -120,9 +123,9 @@ int fscrypt_process_policy(struct file *filp,
ret = -ENOTEMPTY;
else
ret = create_encryption_context_from_policy(inode,
policy);
&policy);
} else if (!is_encryption_context_consistent_with_policy(inode,
policy)) {
&policy)) {
printk(KERN_WARNING
"%s: Policy inconsistent with encryption context\n",
__func__);
@@ -134,11 +137,13 @@ int fscrypt_process_policy(struct file *filp,
mnt_drop_write_file(filp);
return ret;
}
EXPORT_SYMBOL(fscrypt_process_policy);
EXPORT_SYMBOL(fscrypt_ioctl_set_policy);
int fscrypt_get_policy(struct inode *inode, struct fscrypt_policy *policy)
int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
{
struct inode *inode = file_inode(filp);
struct fscrypt_context ctx;
struct fscrypt_policy policy;
int res;
if (!inode->i_sb->s_cop->get_context ||
@@ -151,15 +156,18 @@ int fscrypt_get_policy(struct inode *inode, struct fscrypt_policy *policy)
if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
return -EINVAL;
policy->version = 0;
policy->contents_encryption_mode = ctx.contents_encryption_mode;
policy->filenames_encryption_mode = ctx.filenames_encryption_mode;
policy->flags = ctx.flags;
memcpy(&policy->master_key_descriptor, ctx.master_key_descriptor,
policy.version = 0;
policy.contents_encryption_mode = ctx.contents_encryption_mode;
policy.filenames_encryption_mode = ctx.filenames_encryption_mode;
policy.flags = ctx.flags;
memcpy(policy.master_key_descriptor, ctx.master_key_descriptor,
FS_KEY_DESCRIPTOR_SIZE);
if (copy_to_user(arg, &policy, sizeof(policy)))
return -EFAULT;
return 0;
}
EXPORT_SYMBOL(fscrypt_get_policy);
EXPORT_SYMBOL(fscrypt_ioctl_get_policy);
int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
{