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authorEric Biggers <ebiggers@google.com>2016-12-05 11:12:48 -0800
committerTheodore Ts'o <tytso@mit.edu>2016-12-31 16:26:21 -0500
commitefee590e4a3fa7b66f78aa06eff33f59570ca96d (patch)
tree0bc8ffedf992cd2a6be13796baea2dfef67dfca6 /fs/crypto
parent868e1bc64d04294b76f1c0eedb79e0742be441c7 (diff)
downloadlinux-efee590e4a3fa7b66f78aa06eff33f59570ca96d.tar.bz2
fscrypt: pass up error codes from ->get_context()
It was possible for the ->get_context() operation to fail with a specific error code, which was then not returned to the caller of FS_IOC_SET_ENCRYPTION_POLICY or FS_IOC_GET_ENCRYPTION_POLICY. Make sure to pass through these error codes. Also reorganize the code so that ->get_context() only needs to be called one time when setting an encryption policy, and handle contexts of unrecognized sizes more appropriately. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/crypto')
-rw-r--r--fs/crypto/policy.c54
1 files changed, 23 insertions, 31 deletions
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 521b182dd902..4c99972899c7 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -13,37 +13,20 @@
#include <linux/mount.h>
#include "fscrypt_private.h"
-static int inode_has_encryption_context(struct inode *inode)
-{
- if (!inode->i_sb->s_cop->get_context)
- return 0;
- return (inode->i_sb->s_cop->get_context(inode, NULL, 0L) > 0);
-}
-
/*
- * check whether the policy is consistent with the encryption context
- * for the inode
+ * check whether an encryption policy is consistent with an encryption context
*/
-static int is_encryption_context_consistent_with_policy(struct inode *inode,
+static bool is_encryption_context_consistent_with_policy(
+ const struct fscrypt_context *ctx,
const struct fscrypt_policy *policy)
{
- struct fscrypt_context ctx;
- int res;
-
- if (!inode->i_sb->s_cop->get_context)
- return 0;
-
- res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
- if (res != sizeof(ctx))
- return 0;
-
- return (memcmp(ctx.master_key_descriptor, policy->master_key_descriptor,
- FS_KEY_DESCRIPTOR_SIZE) == 0 &&
- (ctx.flags == policy->flags) &&
- (ctx.contents_encryption_mode ==
- policy->contents_encryption_mode) &&
- (ctx.filenames_encryption_mode ==
- policy->filenames_encryption_mode));
+ return memcmp(ctx->master_key_descriptor, policy->master_key_descriptor,
+ FS_KEY_DESCRIPTOR_SIZE) == 0 &&
+ (ctx->flags == policy->flags) &&
+ (ctx->contents_encryption_mode ==
+ policy->contents_encryption_mode) &&
+ (ctx->filenames_encryption_mode ==
+ policy->filenames_encryption_mode);
}
static int create_encryption_context_from_policy(struct inode *inode,
@@ -90,6 +73,7 @@ int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
struct fscrypt_policy policy;
struct inode *inode = file_inode(filp);
int ret;
+ struct fscrypt_context ctx;
if (copy_from_user(&policy, arg, sizeof(policy)))
return -EFAULT;
@@ -106,7 +90,8 @@ int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
inode_lock(inode);
- if (!inode_has_encryption_context(inode)) {
+ ret = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
+ if (ret == -ENODATA) {
if (!S_ISDIR(inode->i_mode))
ret = -ENOTDIR;
else if (!inode->i_sb->s_cop->empty_dir)
@@ -116,8 +101,13 @@ int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
else
ret = create_encryption_context_from_policy(inode,
&policy);
- } else if (!is_encryption_context_consistent_with_policy(inode,
- &policy)) {
+ } else if (ret == sizeof(ctx) &&
+ is_encryption_context_consistent_with_policy(&ctx,
+ &policy)) {
+ /* The file already uses the same encryption policy. */
+ ret = 0;
+ } else if (ret >= 0 || ret == -ERANGE) {
+ /* The file already uses a different encryption policy. */
ret = -EEXIST;
}
@@ -140,8 +130,10 @@ int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
return -ENODATA;
res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
+ if (res < 0 && res != -ERANGE)
+ return res;
if (res != sizeof(ctx))
- return -ENODATA;
+ return -EINVAL;
if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
return -EINVAL;