diff options
| -rw-r--r-- | Documentation/filesystems/fsverity.rst | 4 | ||||
| -rw-r--r-- | fs/verity/read_metadata.c | 40 | ||||
| -rw-r--r-- | include/uapi/linux/fsverity.h | 1 |
3 files changed, 45 insertions, 0 deletions
diff --git a/Documentation/filesystems/fsverity.rst b/Documentation/filesystems/fsverity.rst index 50b47a6d9ea1..6dc5772037ef 100644 --- a/Documentation/filesystems/fsverity.rst +++ b/Documentation/filesystems/fsverity.rst @@ -235,6 +235,7 @@ need this ioctl. 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 struct fsverity_read_metadata_arg { __u64 metadata_type; @@ -252,6 +253,9 @@ This ioctl takes in a pointer to the following structure:: the same order that their hashes are themselves hashed. See `Merkle tree`_ for more information. +- ``FS_VERITY_METADATA_TYPE_DESCRIPTOR`` reads the fs-verity + descriptor. See `fs-verity descriptor`_. + 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 diff --git a/fs/verity/read_metadata.c b/fs/verity/read_metadata.c index 0f8ad2991cf9..2dea6dd3bb05 100644 --- a/fs/verity/read_metadata.c +++ b/fs/verity/read_metadata.c @@ -76,6 +76,44 @@ static int fsverity_read_merkle_tree(struct inode *inode, } return retval ? retval : err; } + +/* Copy the requested portion of the buffer to userspace. */ +static int fsverity_read_buffer(void __user *dst, u64 offset, int length, + const void *src, size_t src_length) +{ + if (offset >= src_length) + return 0; + src += offset; + src_length -= offset; + + length = min_t(size_t, length, src_length); + + if (copy_to_user(dst, src, length)) + return -EFAULT; + + return length; +} + +static int fsverity_read_descriptor(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; + + /* don't include the signature */ + desc_size = offsetof(struct fsverity_descriptor, signature); + desc->sig_size = 0; + + res = fsverity_read_buffer(buf, offset, length, desc, desc_size); + + kfree(desc); + return res; +} /** * fsverity_ioctl_read_metadata() - read verity metadata from a file * @filp: file to read the metadata from @@ -118,6 +156,8 @@ int fsverity_ioctl_read_metadata(struct file *filp, const void __user *uarg) case FS_VERITY_METADATA_TYPE_MERKLE_TREE: return fsverity_read_merkle_tree(inode, vi, buf, arg.offset, length); + case FS_VERITY_METADATA_TYPE_DESCRIPTOR: + return fsverity_read_descriptor(inode, buf, arg.offset, length); default: return -EINVAL; } diff --git a/include/uapi/linux/fsverity.h b/include/uapi/linux/fsverity.h index 94003b153cb3..41abc283dbcc 100644 --- a/include/uapi/linux/fsverity.h +++ b/include/uapi/linux/fsverity.h @@ -84,6 +84,7 @@ struct fsverity_formatted_digest { }; #define FS_VERITY_METADATA_TYPE_MERKLE_TREE 1 +#define FS_VERITY_METADATA_TYPE_DESCRIPTOR 2 struct fsverity_read_metadata_arg { __u64 metadata_type; |