From: "Darrick J. Wong" Subject: [PATCH 39/47] libext2fs: Add checksum to MMP block Date: Sat, 08 Oct 2011 00:37:25 -0700 Message-ID: <20111008073725.17888.64536.stgit@elm3c44.beaverton.ibm.com> References: <20111008073315.17888.22132.stgit@elm3c44.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: Sunil Mushran , Amir Goldstein , Andi Kleen , Mingming Cao , Joel Becker , linux-ext4@vger.kernel.org, Coly Li To: Andreas Dilger , Theodore Tso , "Darrick J. Wong" Return-path: Received: from e6.ny.us.ibm.com ([32.97.182.146]:50006 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751612Ab1JHHjx (ORCPT ); Sat, 8 Oct 2011 03:39:53 -0400 Received: from d01relay03.pok.ibm.com (d01relay03.pok.ibm.com [9.56.227.235]) by e6.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p987DIY9024454 for ; Sat, 8 Oct 2011 03:13:18 -0400 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay03.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p987bSj5213814 for ; Sat, 8 Oct 2011 03:37:28 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p987bRWu026846 for ; Sat, 8 Oct 2011 04:37:28 -0300 In-Reply-To: <20111008073315.17888.22132.stgit@elm3c44.beaverton.ibm.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Calculate and verify a checksum of the MMP block. Signed-off-by: Darrick J. Wong --- debugfs/debugfs.c | 1 + debugfs/set_fields.c | 1 + lib/ext2fs/csum.c | 35 +++++++++++++++++++++++++++++++++++ lib/ext2fs/ext2_err.et.in | 3 +++ lib/ext2fs/ext2_fs.h | 3 ++- lib/ext2fs/ext2fs.h | 3 +++ lib/ext2fs/mmp.c | 20 ++++++++++++++++++-- lib/ext2fs/swapfs.c | 1 + 8 files changed, 64 insertions(+), 3 deletions(-) diff --git a/debugfs/debugfs.c b/debugfs/debugfs.c index d71de7d..693db62 100644 --- a/debugfs/debugfs.c +++ b/debugfs/debugfs.c @@ -2216,6 +2216,7 @@ void do_dump_mmp(int argc, char *argv[]) fprintf(stdout, "time: %lld -- %s", mmp_s->mmp_time, ctime(&t)); fprintf(stdout, "node_name: %s\n", mmp_s->mmp_nodename); fprintf(stdout, "device_name: %s\n", mmp_s->mmp_bdevname); + fprintf(stdout, "checksum: 0x%08x\n", mmp_s->mmp_checksum); } static int source_file(const char *cmd_file, int sci_idx) diff --git a/debugfs/set_fields.c b/debugfs/set_fields.c index 0103497..0daea66 100644 --- a/debugfs/set_fields.c +++ b/debugfs/set_fields.c @@ -753,6 +753,7 @@ static struct field_set_info mmp_fields[] = { { "bdevname", &set_mmp.mmp_bdevname, NULL, sizeof(set_mmp.mmp_bdevname), parse_string }, { "check_interval", &set_mmp.mmp_check_interval, NULL, 2, parse_uint }, + { "checksum", &set_mmp.mmp_checksum, NULL, 4, parse_uint }, }; void do_set_mmp_value(int argc, char *argv[]) diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c index 9694185..1429d9f 100644 --- a/lib/ext2fs/csum.c +++ b/lib/ext2fs/csum.c @@ -30,6 +30,41 @@ #define STATIC static #endif +static __u32 ext2fs_mmp_csum(ext2_filsys fs, struct mmp_struct *mmp) +{ + int offset = offsetof(struct mmp_struct, mmp_checksum); + __u32 crc; + +#ifdef WORDS_BIGENDIAN + struct mmp_struct swabmmp; + memcpy(&swabmmp, mmp, sizeof(struct mmp_struct)); + ext2fs_swap_mmp(&swabmmp); + mmp = &swabmmp; +#endif + crc = ext2fs_crc32c_le(~0, fs->super->s_uuid, + sizeof(fs->super->s_uuid)); + return ext2fs_crc32c_le(crc, (unsigned char *)mmp, offset); +} + +int ext2fs_mmp_csum_verify(ext2_filsys fs, struct mmp_struct *mmp) +{ + if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) && + (mmp->mmp_checksum != ext2fs_mmp_csum(fs, mmp))) + return 0; + return 1; +} + +errcode_t ext2fs_mmp_csum_set(ext2_filsys fs, struct mmp_struct *mmp) +{ + if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) + return 0; + + mmp->mmp_checksum = ext2fs_mmp_csum(fs, mmp); + return 0; +} + int ext2fs_verify_csum_type(ext2_filsys fs, struct ext2_super_block *sb) { if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in index 3b92eac..403bc61 100644 --- a/lib/ext2fs/ext2_err.et.in +++ b/lib/ext2fs/ext2_err.et.in @@ -461,4 +461,7 @@ ec EXT2_ET_SB_CSUM_INVALID, ec EXT2_ET_UNKNOWN_CSUM, "Unknown checksum algorithm" +ec EXT2_ET_MMP_CSUM_INVALID, + "MMP: invalid checksum" + end diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h index 709fc2f..ef0a288 100644 --- a/lib/ext2fs/ext2_fs.h +++ b/lib/ext2fs/ext2_fs.h @@ -876,7 +876,8 @@ struct mmp_struct { char mmp_bdevname[32]; /* Bdev which last updated MMP block */ __u16 mmp_check_interval; /* Changed mmp_check_interval */ __u16 mmp_pad1; - __u32 mmp_pad2[227]; + __u32 mmp_pad2[226]; + __u32 mmp_checksum; /* crc32c(uuid+mmp_block) */ }; /* diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h index d4d4ecf..ff7ee7b 100644 --- a/lib/ext2fs/ext2fs.h +++ b/lib/ext2fs/ext2fs.h @@ -931,6 +931,8 @@ extern __u32 ext2fs_crc32c_be(__u32 crc, unsigned char const *p, size_t len); extern __u32 ext2fs_crc32c_le(__u32 crc, unsigned char const *p, size_t len); /* csum.c */ +extern errcode_t ext2fs_mmp_csum_set(ext2_filsys fs, struct mmp_struct *mmp); +extern int ext2fs_mmp_csum_verify(ext2_filsys, struct mmp_struct *mmp); extern int ext2fs_verify_csum_type(ext2_filsys fs, struct ext2_super_block *sb); extern errcode_t ext2fs_superblock_csum_set(ext2_filsys fs, struct ext2_super_block *sb); @@ -1420,6 +1422,7 @@ errcode_t ext2fs_mmp_clear(ext2_filsys fs); errcode_t ext2fs_mmp_init(ext2_filsys fs); errcode_t ext2fs_mmp_start(ext2_filsys fs); errcode_t ext2fs_mmp_update(ext2_filsys fs); +errcode_t ext2fs_mmp_update2(ext2_filsys fs, int immediately); errcode_t ext2fs_mmp_stop(ext2_filsys fs); unsigned ext2fs_mmp_new_seq(void); diff --git a/lib/ext2fs/mmp.c b/lib/ext2fs/mmp.c index 91f4fb2..ea2e913 100644 --- a/lib/ext2fs/mmp.c +++ b/lib/ext2fs/mmp.c @@ -103,6 +103,12 @@ errcode_t ext2fs_mmp_read(ext2_filsys fs, blk64_t mmp_blk, void *buf) goto out; } + if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) && + !ext2fs_mmp_csum_verify(fs, mmp_cmp)) { + retval = EXT2_ET_MMP_CSUM_INVALID; + goto out; + } + out: return retval; } @@ -121,6 +127,10 @@ errcode_t ext2fs_mmp_write(ext2_filsys fs, blk64_t mmp_blk, void *buf) fs->super->s_mmp_block > ext2fs_blocks_count(fs->super)) return EXT2_ET_MMP_BAD_BLOCK; + retval = ext2fs_mmp_csum_set(fs, mmp_s); + if (retval) + return retval; + #ifdef WORDS_BIGENDIAN ext2fs_swap_mmp(mmp_s); #endif @@ -381,7 +391,7 @@ mmp_error: /* * Update the on-disk mmp buffer, after checking that it hasn't been changed. */ -errcode_t ext2fs_mmp_update(ext2_filsys fs) +errcode_t ext2fs_mmp_update2(ext2_filsys fs, int immediately) { struct mmp_struct *mmp, *mmp_cmp; struct timeval tv; @@ -392,7 +402,8 @@ errcode_t ext2fs_mmp_update(ext2_filsys fs) return 0; gettimeofday(&tv, 0); - if (tv.tv_sec - fs->mmp_last_written < EXT2_MIN_MMP_UPDATE_INTERVAL) + if (!immediately && + tv.tv_sec - fs->mmp_last_written < EXT2_MIN_MMP_UPDATE_INTERVAL) return 0; retval = ext2fs_mmp_read(fs, fs->super->s_mmp_block, NULL); @@ -412,3 +423,8 @@ errcode_t ext2fs_mmp_update(ext2_filsys fs) mmp_error: return retval; } + +errcode_t ext2fs_mmp_update(ext2_filsys fs) +{ + return ext2fs_mmp_update2(fs, 0); +} diff --git a/lib/ext2fs/swapfs.c b/lib/ext2fs/swapfs.c index de178a4..1295e81 100644 --- a/lib/ext2fs/swapfs.c +++ b/lib/ext2fs/swapfs.c @@ -349,6 +349,7 @@ void ext2fs_swap_mmp(struct mmp_struct *mmp) mmp->mmp_seq = ext2fs_swab32(mmp->mmp_seq); mmp->mmp_time = ext2fs_swab64(mmp->mmp_time); mmp->mmp_check_interval = ext2fs_swab16(mmp->mmp_check_interval); + mmp->mmp_checksum = ext2fs_swab32(mmp->mmp_checksum); } errcode_t ext2fs_dirent_swab_in(ext2_filsys fs, char *buf, int flags)