From: "Darrick J. Wong" Subject: [PATCH 39/51] libext2fs: Add checksum to MMP block Date: Sat, 07 Jan 2012 00:37:05 -0800 Message-ID: <20120107083705.25788.17089.stgit@elm3c44.beaverton.ibm.com> References: <20120107083256.25788.41238.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 e1.ny.us.ibm.com ([32.97.182.141]:47960 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751894Ab2AGIhz (ORCPT ); Sat, 7 Jan 2012 03:37:55 -0500 Received: from /spool/local by e1.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sat, 7 Jan 2012 03:37:54 -0500 Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay05.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q078b84V255296 for ; Sat, 7 Jan 2012 03:37:08 -0500 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q078b7iP000985 for ; Sat, 7 Jan 2012 06:37:08 -0200 In-Reply-To: <20120107083256.25788.41238.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 | 34 ++++++++++++++++++++++++++++++++++ lib/ext2fs/ext2_err.et.in | 3 +++ lib/ext2fs/ext2fs.h | 3 +++ lib/ext2fs/mmp.c | 19 +++++++++++++++++-- lib/ext2fs/swapfs.c | 1 + 7 files changed, 60 insertions(+), 2 deletions(-) diff --git a/debugfs/debugfs.c b/debugfs/debugfs.c index 1d2b2f3..d2e2ff2 100644 --- a/debugfs/debugfs.c +++ b/debugfs/debugfs.c @@ -2248,6 +2248,7 @@ void do_dump_mmp(int argc EXT2FS_ATTR((unused)), char *argv[]) fprintf(stdout, "node_name: %s\n", mmp_s->mmp_nodename); fprintf(stdout, "device_name: %s\n", mmp_s->mmp_bdevname); fprintf(stdout, "magic: 0x%x\n", mmp_s->mmp_magic); + 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 871bf20..986e404 100644 --- a/debugfs/set_fields.c +++ b/debugfs/set_fields.c @@ -256,6 +256,7 @@ 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 }, }; static int check_suffix(const char *field) diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c index 6d8125e..99ca652 100644 --- a/lib/ext2fs/csum.c +++ b/lib/ext2fs/csum.c @@ -30,6 +30,40 @@ #define STATIC static #endif +static __u32 ext2fs_mmp_csum(ext2_filsys fs, struct mmp_struct *mmp) +{ + int offset = offsetof(struct mmp_struct, mmp_checksum); + + return ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)mmp, offset); +} + +int ext2fs_mmp_csum_verify(ext2_filsys fs, struct mmp_struct *mmp) +{ + __u32 calculated; + + if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) + return 1; + + calculated = ext2fs_mmp_csum(fs, mmp); + + return ext2fs_le32_to_cpu(mmp->mmp_checksum) == calculated; +} + +errcode_t ext2fs_mmp_csum_set(ext2_filsys fs, struct mmp_struct *mmp) +{ + __u32 crc; + + if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) + return 0; + + crc = ext2fs_mmp_csum(fs, mmp); + mmp->mmp_checksum = ext2fs_cpu_to_le32(crc); + + 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 01f9f7b..a42ed9a 100644 --- a/lib/ext2fs/ext2_err.et.in +++ b/lib/ext2fs/ext2_err.et.in @@ -467,4 +467,7 @@ ec EXT2_ET_SB_CSUM_INVALID, ec EXT2_ET_UNKNOWN_CSUM, "Unknown checksum algorithm" +ec EXT2_ET_MMP_CSUM_INVALID, + "MMP block checksum does not match MMP block" + end diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h index 22c614c..10113f7 100644 --- a/lib/ext2fs/ext2fs.h +++ b/lib/ext2fs/ext2fs.h @@ -943,6 +943,8 @@ 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); @@ -1431,6 +1433,7 @@ 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 b27d9a4..20a98f5 100644 --- a/lib/ext2fs/mmp.c +++ b/lib/ext2fs/mmp.c @@ -91,6 +91,11 @@ errcode_t ext2fs_mmp_read(ext2_filsys fs, blk64_t mmp_blk, void *buf) } mmp_cmp = fs->mmp_cmp; + + if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) && + !ext2fs_mmp_csum_verify(fs, mmp_cmp)) + retval = EXT2_ET_MMP_CSUM_INVALID; + #ifdef WORDS_BIGENDIAN ext2fs_swap_mmp(mmp_cmp); #endif @@ -125,6 +130,10 @@ errcode_t ext2fs_mmp_write(ext2_filsys fs, blk64_t mmp_blk, void *buf) ext2fs_swap_mmp(mmp_s); #endif + retval = ext2fs_mmp_csum_set(fs, mmp_s); + if (retval) + return retval; + /* I was tempted to make this use O_DIRECT and the mmp_fd, but * this caused no end of grief, while leaving it as-is works. */ retval = io_channel_write_blk64(fs->io, mmp_blk, -(int)sizeof(struct mmp_struct), buf); @@ -381,7 +390,7 @@ 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 +401,8 @@ 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 +422,8 @@ 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)