From efee590e4a3fa7b66f78aa06eff33f59570ca96d Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 5 Dec 2016 11:12:48 -0800 Subject: [PATCH] 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 Signed-off-by: Theodore Ts'o --- fs/crypto/policy.c | 54 ++++++++++++++++++++-------------------------- 1 file 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 #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; -- 2.30.2