diff options
| -rw-r--r-- | Documentation/filesystems/fsverity.rst | 9 | ||||
| -rw-r--r-- | fs/verity/read_metadata.c | 30 | ||||
| -rw-r--r-- | include/uapi/linux/fsverity.h | 1 |
3 files changed, 39 insertions, 1 deletions
diff --git a/Documentation/filesystems/fsverity.rst b/Documentation/filesystems/fsverity.rst index 6dc5772037ef..1d831e3cbcb3 100644 --- a/Documentation/filesystems/fsverity.rst +++ b/Documentation/filesystems/fsverity.rst @@ -236,6 +236,7 @@ This ioctl takes in a pointer to the following structure:: #define FS_VERITY_METADATA_TYPE_MERKLE_TREE 1 #define FS_VERITY_METADATA_TYPE_DESCRIPTOR 2 + #define FS_VERITY_METADATA_TYPE_SIGNATURE 3 struct fsverity_read_metadata_arg { __u64 metadata_type; @@ -256,6 +257,10 @@ This ioctl takes in a pointer to the following structure:: - ``FS_VERITY_METADATA_TYPE_DESCRIPTOR`` reads the fs-verity descriptor. See `fs-verity descriptor`_. +- ``FS_VERITY_METADATA_TYPE_SIGNATURE`` reads the signature which was + passed to FS_IOC_ENABLE_VERITY, if any. See `Built-in signature + verification`_. + The semantics are similar to those of ``pread()``. ``offset`` specifies the offset in bytes into the metadata item to read from, and ``length`` specifies the maximum number of bytes to read from the @@ -279,7 +284,9 @@ FS_IOC_READ_VERITY_METADATA can fail with the following errors: - ``EINTR``: the ioctl was interrupted before any data was read - ``EINVAL``: reserved fields were set, or ``offset + length`` overflowed -- ``ENODATA``: the file is not a verity file +- ``ENODATA``: the file is not a verity file, or + FS_VERITY_METADATA_TYPE_SIGNATURE was requested but the file doesn't + have a built-in signature - ``ENOTTY``: this type of filesystem does not implement fs-verity, or this ioctl is not yet implemented on it - ``EOPNOTSUPP``: the kernel was not configured with fs-verity diff --git a/fs/verity/read_metadata.c b/fs/verity/read_metadata.c index 2dea6dd3bb05..7e2d0c7bdf0d 100644 --- a/fs/verity/read_metadata.c +++ b/fs/verity/read_metadata.c @@ -114,6 +114,34 @@ static int fsverity_read_descriptor(struct inode *inode, kfree(desc); return res; } + +static int fsverity_read_signature(struct inode *inode, + void __user *buf, u64 offset, int length) +{ + struct fsverity_descriptor *desc; + size_t desc_size; + int res; + + res = fsverity_get_descriptor(inode, &desc, &desc_size); + if (res) + return res; + + if (desc->sig_size == 0) { + res = -ENODATA; + goto out; + } + + /* + * Include only the signature. Note that fsverity_get_descriptor() + * already verified that sig_size is in-bounds. + */ + res = fsverity_read_buffer(buf, offset, length, desc->signature, + le32_to_cpu(desc->sig_size)); +out: + kfree(desc); + return res; +} + /** * fsverity_ioctl_read_metadata() - read verity metadata from a file * @filp: file to read the metadata from @@ -158,6 +186,8 @@ int fsverity_ioctl_read_metadata(struct file *filp, const void __user *uarg) length); case FS_VERITY_METADATA_TYPE_DESCRIPTOR: return fsverity_read_descriptor(inode, buf, arg.offset, length); + case FS_VERITY_METADATA_TYPE_SIGNATURE: + return fsverity_read_signature(inode, buf, arg.offset, length); default: return -EINVAL; } diff --git a/include/uapi/linux/fsverity.h b/include/uapi/linux/fsverity.h index 41abc283dbcc..15384e22e331 100644 --- a/include/uapi/linux/fsverity.h +++ b/include/uapi/linux/fsverity.h @@ -85,6 +85,7 @@ struct fsverity_formatted_digest { #define FS_VERITY_METADATA_TYPE_MERKLE_TREE 1 #define FS_VERITY_METADATA_TYPE_DESCRIPTOR 2 +#define FS_VERITY_METADATA_TYPE_SIGNATURE 3 struct fsverity_read_metadata_arg { __u64 metadata_type; |