From: Eric Biggers <ebiggers@kernel.org> To: linux-fscrypt@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-integrity@vger.kernel.org, linux-api@vger.kernel.org, "Theodore Y . Ts'o" <tytso@mit.edu>, Jaegeuk Kim <jaegeuk@kernel.org>, Victor Hsieh <victorhsieh@google.com> Subject: [PATCH v3 10/15] fs-verity: implement FS_IOC_MEASURE_VERITY ioctl Date: Thu, 23 May 2019 09:18:06 -0700 [thread overview] Message-ID: <20190523161811.6259-11-ebiggers@kernel.org> (raw) In-Reply-To: <20190523161811.6259-1-ebiggers@kernel.org> From: Eric Biggers <ebiggers@google.com> Add a function for filesystems to call to implement the FS_IOC_MEASURE_VERITY ioctl. This ioctl retrieves the file measurement that fs-verity calculated for the given file and is enforcing for reads; i.e., reads that don't match this hash will fail. This ioctl can be used for authentication or logging of file measurements in userspace. See the "FS_IOC_MEASURE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Signed-off-by: Eric Biggers <ebiggers@google.com> --- fs/verity/Makefile | 1 + fs/verity/measure.c | 57 ++++++++++++++++++++++++++++++++++++++++ include/linux/fsverity.h | 11 ++++++++ 3 files changed, 69 insertions(+) create mode 100644 fs/verity/measure.c diff --git a/fs/verity/Makefile b/fs/verity/Makefile index 04b37475fd280..6f7675ae0a311 100644 --- a/fs/verity/Makefile +++ b/fs/verity/Makefile @@ -3,5 +3,6 @@ obj-$(CONFIG_FS_VERITY) += enable.o \ hash_algs.o \ init.o \ + measure.o \ open.o \ verify.o diff --git a/fs/verity/measure.c b/fs/verity/measure.c new file mode 100644 index 0000000000000..f29557c0ee3da --- /dev/null +++ b/fs/verity/measure.c @@ -0,0 +1,57 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * fs/verity/measure.c: ioctl to get a verity file's measurement + * + * Copyright 2019 Google LLC + */ + +#include "fsverity_private.h" + +#include <linux/uaccess.h> + +/** + * fsverity_ioctl_measure() - get a verity file's measurement + * + * Retrieve the file measurement that the kernel is enforcing for reads from a + * verity file. See the "FS_IOC_MEASURE_VERITY" section of + * Documentation/filesystems/fsverity.rst for the documentation. + * + * Return: 0 on success, -errno on failure + */ +int fsverity_ioctl_measure(struct file *filp, void __user *_uarg) +{ + const struct inode *inode = file_inode(filp); + struct fsverity_digest __user *uarg = _uarg; + const struct fsverity_info *vi; + const struct fsverity_hash_alg *hash_alg; + struct fsverity_digest arg; + + vi = get_verity_info(inode); + if (!vi) + return -ENODATA; /* not a verity file */ + hash_alg = vi->tree_params.hash_alg; + + /* + * The user specifies the digest_size their buffer has space for; we can + * return the digest if it fits in the available space. We write back + * the actual size, which may be shorter than the user-specified size. + */ + + if (get_user(arg.digest_size, &uarg->digest_size)) + return -EFAULT; + if (arg.digest_size < hash_alg->digest_size) + return -EOVERFLOW; + + memset(&arg, 0, sizeof(arg)); + arg.digest_algorithm = hash_alg - fsverity_hash_algs; + arg.digest_size = hash_alg->digest_size; + + if (copy_to_user(uarg, &arg, sizeof(arg))) + return -EFAULT; + + if (copy_to_user(uarg->digest, vi->measurement, hash_alg->digest_size)) + return -EFAULT; + + return 0; +} +EXPORT_SYMBOL_GPL(fsverity_ioctl_measure); diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h index 9a84fe4bcfc88..df0b620c6897f 100644 --- a/include/linux/fsverity.h +++ b/include/linux/fsverity.h @@ -110,6 +110,10 @@ struct fsverity_operations { extern int fsverity_ioctl_enable(struct file *filp, const void __user *arg); +/* measure.c */ + +extern int fsverity_ioctl_measure(struct file *filp, void __user *arg); + /* open.c */ extern int fsverity_file_open(struct inode *inode, struct file *filp); @@ -132,6 +136,13 @@ static inline int fsverity_ioctl_enable(struct file *filp, return -EOPNOTSUPP; } +/* measure.c */ + +static inline int fsverity_ioctl_measure(struct file *filp, void __user *arg) +{ + return -EOPNOTSUPP; +} + /* open.c */ static inline int fsverity_file_open(struct inode *inode, struct file *filp) -- 2.21.0
WARNING: multiple messages have this Message-ID (diff)
From: Eric Biggers <ebiggers@kernel.org> To: linux-fscrypt@vger.kernel.org Cc: "Theodore Y . Ts'o" <tytso@mit.edu>, linux-api@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, Jaegeuk Kim <jaegeuk@kernel.org>, linux-integrity@vger.kernel.org, linux-ext4@vger.kernel.org, Victor Hsieh <victorhsieh@google.com> Subject: [PATCH v3 10/15] fs-verity: implement FS_IOC_MEASURE_VERITY ioctl Date: Thu, 23 May 2019 09:18:06 -0700 [thread overview] Message-ID: <20190523161811.6259-11-ebiggers@kernel.org> (raw) In-Reply-To: <20190523161811.6259-1-ebiggers@kernel.org> From: Eric Biggers <ebiggers@google.com> Add a function for filesystems to call to implement the FS_IOC_MEASURE_VERITY ioctl. This ioctl retrieves the file measurement that fs-verity calculated for the given file and is enforcing for reads; i.e., reads that don't match this hash will fail. This ioctl can be used for authentication or logging of file measurements in userspace. See the "FS_IOC_MEASURE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Signed-off-by: Eric Biggers <ebiggers@google.com> --- fs/verity/Makefile | 1 + fs/verity/measure.c | 57 ++++++++++++++++++++++++++++++++++++++++ include/linux/fsverity.h | 11 ++++++++ 3 files changed, 69 insertions(+) create mode 100644 fs/verity/measure.c diff --git a/fs/verity/Makefile b/fs/verity/Makefile index 04b37475fd280..6f7675ae0a311 100644 --- a/fs/verity/Makefile +++ b/fs/verity/Makefile @@ -3,5 +3,6 @@ obj-$(CONFIG_FS_VERITY) += enable.o \ hash_algs.o \ init.o \ + measure.o \ open.o \ verify.o diff --git a/fs/verity/measure.c b/fs/verity/measure.c new file mode 100644 index 0000000000000..f29557c0ee3da --- /dev/null +++ b/fs/verity/measure.c @@ -0,0 +1,57 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * fs/verity/measure.c: ioctl to get a verity file's measurement + * + * Copyright 2019 Google LLC + */ + +#include "fsverity_private.h" + +#include <linux/uaccess.h> + +/** + * fsverity_ioctl_measure() - get a verity file's measurement + * + * Retrieve the file measurement that the kernel is enforcing for reads from a + * verity file. See the "FS_IOC_MEASURE_VERITY" section of + * Documentation/filesystems/fsverity.rst for the documentation. + * + * Return: 0 on success, -errno on failure + */ +int fsverity_ioctl_measure(struct file *filp, void __user *_uarg) +{ + const struct inode *inode = file_inode(filp); + struct fsverity_digest __user *uarg = _uarg; + const struct fsverity_info *vi; + const struct fsverity_hash_alg *hash_alg; + struct fsverity_digest arg; + + vi = get_verity_info(inode); + if (!vi) + return -ENODATA; /* not a verity file */ + hash_alg = vi->tree_params.hash_alg; + + /* + * The user specifies the digest_size their buffer has space for; we can + * return the digest if it fits in the available space. We write back + * the actual size, which may be shorter than the user-specified size. + */ + + if (get_user(arg.digest_size, &uarg->digest_size)) + return -EFAULT; + if (arg.digest_size < hash_alg->digest_size) + return -EOVERFLOW; + + memset(&arg, 0, sizeof(arg)); + arg.digest_algorithm = hash_alg - fsverity_hash_algs; + arg.digest_size = hash_alg->digest_size; + + if (copy_to_user(uarg, &arg, sizeof(arg))) + return -EFAULT; + + if (copy_to_user(uarg->digest, vi->measurement, hash_alg->digest_size)) + return -EFAULT; + + return 0; +} +EXPORT_SYMBOL_GPL(fsverity_ioctl_measure); diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h index 9a84fe4bcfc88..df0b620c6897f 100644 --- a/include/linux/fsverity.h +++ b/include/linux/fsverity.h @@ -110,6 +110,10 @@ struct fsverity_operations { extern int fsverity_ioctl_enable(struct file *filp, const void __user *arg); +/* measure.c */ + +extern int fsverity_ioctl_measure(struct file *filp, void __user *arg); + /* open.c */ extern int fsverity_file_open(struct inode *inode, struct file *filp); @@ -132,6 +136,13 @@ static inline int fsverity_ioctl_enable(struct file *filp, return -EOPNOTSUPP; } +/* measure.c */ + +static inline int fsverity_ioctl_measure(struct file *filp, void __user *arg) +{ + return -EOPNOTSUPP; +} + /* open.c */ static inline int fsverity_file_open(struct inode *inode, struct file *filp) -- 2.21.0
next prev parent reply other threads:[~2019-05-23 16:18 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-05-23 16:17 [f2fs-dev] [PATCH v3 00/15] fs-verity: read-only file-based authenticity protection Eric Biggers 2019-05-23 16:17 ` Eric Biggers 2019-05-23 16:17 ` Eric Biggers 2019-05-23 16:17 ` [PATCH v3 01/15] fs-verity: add a documentation file Eric Biggers 2019-05-23 16:17 ` Eric Biggers 2019-05-23 16:17 ` [PATCH v3 02/15] fs-verity: add MAINTAINERS file entry Eric Biggers 2019-05-23 16:17 ` Eric Biggers 2019-05-23 16:17 ` [PATCH v3 03/15] fs-verity: add UAPI header Eric Biggers 2019-05-23 16:17 ` Eric Biggers 2019-05-23 16:18 ` [f2fs-dev] [PATCH v3 04/15] fs-verity: add Kconfig and the helper functions for hashing Eric Biggers 2019-05-23 16:18 ` Eric Biggers 2019-05-23 16:18 ` Eric Biggers 2019-05-23 16:18 ` [PATCH v3 05/15] fs-verity: add inode and superblock fields Eric Biggers 2019-05-23 16:18 ` Eric Biggers 2019-05-23 16:18 ` [PATCH v3 06/15] fs-verity: add the hook for file ->open() Eric Biggers 2019-05-23 16:18 ` Eric Biggers 2019-05-23 16:18 ` [f2fs-dev] [PATCH v3 07/15] fs-verity: add the hook for file ->setattr() Eric Biggers 2019-05-23 16:18 ` Eric Biggers 2019-05-23 16:18 ` Eric Biggers 2019-05-23 16:18 ` [PATCH v3 08/15] fs-verity: add data verification hooks for ->readpages() Eric Biggers 2019-05-23 16:18 ` Eric Biggers 2019-05-23 16:18 ` [PATCH v3 09/15] fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Eric Biggers 2019-05-23 16:18 ` Eric Biggers 2019-05-23 16:18 ` Eric Biggers [this message] 2019-05-23 16:18 ` [PATCH v3 10/15] fs-verity: implement FS_IOC_MEASURE_VERITY ioctl Eric Biggers 2019-05-23 16:18 ` [PATCH v3 11/15] fs-verity: add SHA-512 support Eric Biggers 2019-05-23 16:18 ` Eric Biggers 2019-05-23 16:18 ` [PATCH v3 12/15] fs-verity: support builtin file signatures Eric Biggers 2019-05-23 16:18 ` Eric Biggers 2019-05-23 16:18 ` [PATCH v3 13/15] ext4: add basic fs-verity support Eric Biggers 2019-05-23 16:18 ` Eric Biggers 2019-05-23 16:18 ` [PATCH v3 14/15] ext4: add fs-verity read support Eric Biggers 2019-05-23 16:18 ` Eric Biggers 2019-05-23 16:18 ` [PATCH v3 15/15] f2fs: add fs-verity support Eric Biggers 2019-05-23 16:18 ` Eric Biggers 2019-05-30 18:54 ` [PATCH v3 00/15] fs-verity: read-only file-based authenticity protection Eric Biggers
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