Messages in this thread | | | Date | Fri, 14 Jul 2023 12:29:35 +0800 | Subject | Re: [PATCH] erofs: deprecate superblock checksum feature | From | Gao Xiang <> |
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On 2023/7/14 11:38, Jingbo Xu wrote: > Later we're going to introduce fs-verity based verification for the > whole image. Make the superblock checksum feature deprecated.
I'd suggest that
"Later we're going to try the self-contained image verification. The current superblock checksum feature has quite limited functionality, instead, merkle trees can provide better protection for image integrity.
Since the superblock checksum is a compatible feature, just deprecate now. "
> > Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com> > --- > fs/erofs/Kconfig | 1 - > fs/erofs/super.c | 44 +++++--------------------------------------- > 2 files changed, 5 insertions(+), 40 deletions(-) > > diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig > index f259d92c9720..ebcb1f6a426a 100644 > --- a/fs/erofs/Kconfig > +++ b/fs/erofs/Kconfig > @@ -4,7 +4,6 @@ config EROFS_FS > tristate "EROFS filesystem support" > depends on BLOCK > select FS_IOMAP > - select LIBCRC32C > help > EROFS (Enhanced Read-Only File System) is a lightweight read-only > file system with modern designs (e.g. no buffer heads, inline > diff --git a/fs/erofs/super.c b/fs/erofs/super.c > index 9d6a3c6158bd..bb6a966ac4d4 100644 > --- a/fs/erofs/super.c > +++ b/fs/erofs/super.c > @@ -8,7 +8,6 @@ > #include <linux/statfs.h> > #include <linux/parser.h> > #include <linux/seq_file.h> > -#include <linux/crc32c.h> > #include <linux/fs_context.h> > #include <linux/fs_parser.h> > #include <linux/dax.h> > @@ -51,33 +50,6 @@ void _erofs_info(struct super_block *sb, const char *function, > va_end(args); > } > > -static int erofs_superblock_csum_verify(struct super_block *sb, void *sbdata) > -{ > - size_t len = 1 << EROFS_SB(sb)->blkszbits; > - struct erofs_super_block *dsb; > - u32 expected_crc, crc; > - > - if (len > EROFS_SUPER_OFFSET) > - len -= EROFS_SUPER_OFFSET; > - > - dsb = kmemdup(sbdata + EROFS_SUPER_OFFSET, len, GFP_KERNEL); > - if (!dsb) > - return -ENOMEM; > - > - expected_crc = le32_to_cpu(dsb->checksum); > - dsb->checksum = 0; > - /* to allow for x86 boot sectors and other oddities. */ > - crc = crc32c(~0, dsb, len); > - kfree(dsb); > - > - if (crc != expected_crc) { > - erofs_err(sb, "invalid checksum 0x%08x, 0x%08x expected", > - crc, expected_crc); > - return -EBADMSG; > - } > - return 0; > -} > - > static void erofs_inode_init_once(void *ptr) > { > struct erofs_inode *vi = ptr; > @@ -113,15 +85,16 @@ static void erofs_free_inode(struct inode *inode) > static bool check_layout_compatibility(struct super_block *sb, > struct erofs_super_block *dsb) > { > - const unsigned int feature = le32_to_cpu(dsb->feature_incompat); > + struct erofs_sb_info *sbi = EROFS_SB(sb); > > - EROFS_SB(sb)->feature_incompat = feature; > + sbi->feature_compat = le32_to_cpu(dsb->feature_compat); > + sbi->feature_incompat = le32_to_cpu(dsb->feature_incompat); > > /* check if current kernel meets all mandatory requirements */ > - if (feature & (~EROFS_ALL_FEATURE_INCOMPAT)) { > + if (sbi->feature_incompat & (~EROFS_ALL_FEATURE_INCOMPAT)) { > erofs_err(sb, > "unidentified incompatible feature %x, please upgrade kernel version", > - feature & ~EROFS_ALL_FEATURE_INCOMPAT); > + sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT); > return false; > } > return true; > @@ -365,13 +338,6 @@ static int erofs_read_superblock(struct super_block *sb) > goto out; > } > > - sbi->feature_compat = le32_to_cpu(dsb->feature_compat); > - if (erofs_sb_has_sb_chksum(sbi)) { > - ret = erofs_superblock_csum_verify(sb, data); > - if (ret) > - goto out; > - } > - > ret = -EINVAL; > if (!check_layout_compatibility(sb, dsb)) > goto out;
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