| Message ID | 20190522081910.7689-14-jthumshirn@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add support for other checksums | expand |
On Wed, May 22, 2019 at 10:19:10AM +0200, Johannes Thumshirn wrote: > Now that we everything in place, we can add SHA-256 as another checksum > algorithm. > > SHA-256 was taken as it was the cryptographically strongest algorithm that > can fit into the 32 Bytes we have left. > > Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> > > --- > changes to v2: > - Add pre dependency on sha256 > Changes to v1: > - Select SHA-256 in KConfig > - Minimalize switch() in btrfs_supported_super_csum() (Nikolay) > - Use enum for new on-disk checksum type (Nikolay/David) > - Format SHA256 using sprintf()'s hexdump mode > --- > fs/btrfs/Kconfig | 1 + > fs/btrfs/btrfs_inode.h | 3 +++ > fs/btrfs/ctree.h | 4 ++-- > fs/btrfs/disk-io.c | 1 + > fs/btrfs/super.c | 1 + > include/uapi/linux/btrfs_tree.h | 6 ++++-- > 6 files changed, 12 insertions(+), 4 deletions(-) > > diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig > index 212b4a854f2c..2521a24f74be 100644 > --- a/fs/btrfs/Kconfig > +++ b/fs/btrfs/Kconfig > @@ -4,6 +4,7 @@ config BTRFS_FS > tristate "Btrfs filesystem support" > select CRYPTO > select CRYPTO_CRC32C > + select CRYPTO_SHA256 > select ZLIB_INFLATE > select ZLIB_DEFLATE > select LZO_COMPRESS > diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h > index e79fd9129075..125bc7f3b871 100644 > --- a/fs/btrfs/btrfs_inode.h > +++ b/fs/btrfs/btrfs_inode.h > @@ -346,6 +346,9 @@ static inline void btrfs_csum_format(struct btrfs_super_block *sb, > case BTRFS_CSUM_TYPE_CRC32: > snprintf(cbuf, size, "0x%08x", *(u32 *)csum); > break; > + case BTRFS_CSUM_TYPE_SHA256: > + snprintf(cbuf, size, "%*phN", (int)size / 8, csum); This seems to print the buffer in the host order ('h', other formats use that). I wonder if there needs to be some caution about endianity here. Ideally we won't need to care and just use the right format that will printk handle transparently for us.
diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig index 212b4a854f2c..2521a24f74be 100644 --- a/fs/btrfs/Kconfig +++ b/fs/btrfs/Kconfig @@ -4,6 +4,7 @@ config BTRFS_FS tristate "Btrfs filesystem support" select CRYPTO select CRYPTO_CRC32C + select CRYPTO_SHA256 select ZLIB_INFLATE select ZLIB_DEFLATE select LZO_COMPRESS diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h index e79fd9129075..125bc7f3b871 100644 --- a/fs/btrfs/btrfs_inode.h +++ b/fs/btrfs/btrfs_inode.h @@ -346,6 +346,9 @@ static inline void btrfs_csum_format(struct btrfs_super_block *sb, case BTRFS_CSUM_TYPE_CRC32: snprintf(cbuf, size, "0x%08x", *(u32 *)csum); break; + case BTRFS_CSUM_TYPE_SHA256: + snprintf(cbuf, size, "%*phN", (int)size / 8, csum); + break; default: /* can't happen - csum type is validated at mount time */ break; } diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 8b635ca370f5..f2246aa2596a 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -72,8 +72,8 @@ struct btrfs_ref; #define BTRFS_LINK_MAX 65535U /* four bytes for CRC32 */ -static const int btrfs_csum_sizes[] = { 4 }; -static char *btrfs_csum_names[] = { "crc32c" }; +static const int btrfs_csum_sizes[] = { 4, 32 }; +static char *btrfs_csum_names[] = { "crc32c", "sha256" }; #define BTRFS_EMPTY_DIR_SIZE 0 diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 68cdee36b470..0c7ea5c7f0db 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -357,6 +357,7 @@ static bool btrfs_supported_super_csum(u16 csum_type) { switch (csum_type) { case BTRFS_CSUM_TYPE_CRC32: + case BTRFS_CSUM_TYPE_SHA256: return true; default: return false; diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index f40516ca5963..5d3687354fc7 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -2466,3 +2466,4 @@ module_exit(exit_btrfs_fs) MODULE_LICENSE("GPL"); MODULE_SOFTDEP("pre: crc32c"); +MODULE_SOFTDEP("pre: sha256"); diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h index 421239b98db2..8edb624410cb 100644 --- a/include/uapi/linux/btrfs_tree.h +++ b/include/uapi/linux/btrfs_tree.h @@ -300,8 +300,10 @@ #define BTRFS_CSUM_SIZE 32 /* csum types */ -#define BTRFS_CSUM_TYPE_CRC32 0 - +enum { + BTRFS_CSUM_TYPE_CRC32 = 0, + BTRFS_CSUM_TYPE_SHA256 = 1, +}; /* * flags definitions for directory entry item type *
Now that we everything in place, we can add SHA-256 as another checksum algorithm. SHA-256 was taken as it was the cryptographically strongest algorithm that can fit into the 32 Bytes we have left. Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> --- changes to v2: - Add pre dependency on sha256 Changes to v1: - Select SHA-256 in KConfig - Minimalize switch() in btrfs_supported_super_csum() (Nikolay) - Use enum for new on-disk checksum type (Nikolay/David) - Format SHA256 using sprintf()'s hexdump mode --- fs/btrfs/Kconfig | 1 + fs/btrfs/btrfs_inode.h | 3 +++ fs/btrfs/ctree.h | 4 ++-- fs/btrfs/disk-io.c | 1 + fs/btrfs/super.c | 1 + include/uapi/linux/btrfs_tree.h | 6 ++++-- 6 files changed, 12 insertions(+), 4 deletions(-)