libext2fs: verify and calculate extended attribute block checksums

Calculate and verify the checksum for separate (i.e. not in the inode)
extended attribute blocks; the checksum lives in the header.

[ Merged in change from Tao so that we always use the fs checksum seed
  for the xattr blocks. ]

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index 2d39d03..06a5314 100644 (file)
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -1518,7 +1518,8 @@ static void adjust_extattr_refcount(e2fsck_t ctx, ext2_refcount_t refcount,
                if ((blk = ea_refcount_intr_next(refcount, &count)) == 0)
                        break;
                pctx.blk = blk;
-               pctx.errcode = ext2fs_read_ext_attr2(fs, blk, block_buf);
+               pctx.errcode = ext2fs_read_ext_attr3(fs, blk, block_buf,
+                                                    pctx.ino);
                if (pctx.errcode) {
                        fix_problem(ctx, PR_1_EXTATTR_READ_ABORT, &pctx);
                        return;
@@ -1529,8 +1530,9 @@ static void adjust_extattr_refcount(e2fsck_t ctx, ext2_refcount_t refcount,
                pctx.num = should_be;
                if (fix_problem(ctx, PR_1_EXTATTR_REFCOUNT, &pctx)) {
                        header->h_refcount = should_be;
-                       pctx.errcode = ext2fs_write_ext_attr2(fs, blk,
-                                                            block_buf);
+                       pctx.errcode = ext2fs_write_ext_attr3(fs, blk,
+                                                            block_buf,
+                                                            pctx.ino);
                        if (pctx.errcode) {
                                fix_problem(ctx, PR_1_EXTATTR_WRITE_ABORT,
                                            &pctx);
@@ -1628,7 +1630,7 @@ static int check_ext_attr(e2fsck_t ctx, struct problem_context *pctx,
         * validate it
         */
        pctx->blk = blk;
-       pctx->errcode = ext2fs_read_ext_attr2(fs, blk, block_buf);
+       pctx->errcode = ext2fs_read_ext_attr3(fs, blk, block_buf, pctx->ino);
        if (pctx->errcode && fix_problem(ctx, PR_1_READ_EA_BLOCK, pctx))
                goto clear_extattr;
        header = (struct ext2_ext_attr_header *) block_buf;

diff --git a/e2fsck/pass1b.c b/e2fsck/pass1b.c
index 93fb630..05cbd10 100644 (file)
--- a/e2fsck/pass1b.c
+++ b/e2fsck/pass1b.c
@@ -653,9 +653,9 @@ static void delete_file(e2fsck_t ctx, ext2_ino_t ino,
        if (ext2fs_file_acl_block(fs, &inode) &&
            (fs->super->s_feature_compat & EXT2_FEATURE_COMPAT_EXT_ATTR)) {
                count = 1;
-               pctx.errcode = ext2fs_adjust_ea_refcount2(fs,
+               pctx.errcode = ext2fs_adjust_ea_refcount3(fs,
                                        ext2fs_file_acl_block(fs, &inode),
-                                                  block_buf, -1, &count);
+                                       block_buf, -1, &count, ino);
                if (pctx.errcode == EXT2_ET_BAD_EA_BLOCK_NUM) {
                        pctx.errcode = 0;
                        count = 1;

diff --git a/e2fsck/pass2.c b/e2fsck/pass2.c
index be950de..e28af61 100644 (file)
--- a/e2fsck/pass2.c
+++ b/e2fsck/pass2.c
@@ -1290,9 +1290,9 @@ static void deallocate_inode(e2fsck_t ctx, ext2_ino_t ino, char* block_buf)
 
        if (ext2fs_file_acl_block(fs, &inode) &&
            (fs->super->s_feature_compat & EXT2_FEATURE_COMPAT_EXT_ATTR)) {
-               pctx.errcode = ext2fs_adjust_ea_refcount2(fs,
-                                       ext2fs_file_acl_block(fs, &inode),
-                                       block_buf, -1, &count);
+               pctx.errcode = ext2fs_adjust_ea_refcount3(fs,
+                               ext2fs_file_acl_block(fs, &inode),
+                               block_buf, -1, &count, ino);
                if (pctx.errcode == EXT2_ET_BAD_EA_BLOCK_NUM) {
                        pctx.errcode = 0;
                        count = 1;

diff --git a/e2fsck/super.c b/e2fsck/super.c
index a5e8005..a8fe571 100644 (file)
--- a/e2fsck/super.c
+++ b/e2fsck/super.c
@@ -199,9 +199,9 @@ static int release_inode_blocks(e2fsck_t ctx, ext2_ino_t ino,
                ext2fs_iblk_sub_blocks(fs, inode, pb.truncated_blocks);
 
        if (ext2fs_file_acl_block(fs, inode)) {
-               retval = ext2fs_adjust_ea_refcount2(fs,
-                                       ext2fs_file_acl_block(fs, inode),
-                                       block_buf, -1, &count);
+               retval = ext2fs_adjust_ea_refcount3(fs,
+                               ext2fs_file_acl_block(fs, inode),
+                               block_buf, -1, &count, ino);
                if (retval == EXT2_ET_BAD_EA_BLOCK_NUM) {
                        retval = 0;
                        count = 1;

diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c
index e92bac5..8325fb5 100644 (file)
--- a/lib/ext2fs/csum.c
+++ b/lib/ext2fs/csum.c
@@ -30,6 +30,62 @@
 #define STATIC static
 #endif
 
+static errcode_t ext2fs_ext_attr_block_csum(ext2_filsys fs, ext2_ino_t inum,
+                                           blk64_t block,
+                                           struct ext2_ext_attr_header *hdr,
+                                           __u32 *crc)
+{
+       errcode_t retval;
+       char *buf = (char *)hdr;
+       __u32 gen, old_crc = hdr->h_checksum;
+       struct ext2_inode inode;
+
+       hdr->h_checksum = 0;
+       block = ext2fs_cpu_to_le64(block);
+       *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&block,
+                               sizeof(block));
+       *crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, fs->blocksize);
+       hdr->h_checksum = old_crc;
+
+       return 0;
+}
+
+int ext2fs_ext_attr_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
+                                     blk64_t block,
+                                     struct ext2_ext_attr_header *hdr)
+{
+       __u32 calculated;
+       errcode_t retval;
+
+       if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+                                       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+               return 1;
+
+       retval = ext2fs_ext_attr_block_csum(fs, inum, block, hdr, &calculated);
+       if (retval)
+               return 0;
+
+       return ext2fs_le32_to_cpu(hdr->h_checksum) == calculated;
+}
+
+errcode_t ext2fs_ext_attr_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
+                                        blk64_t block,
+                                        struct ext2_ext_attr_header *hdr)
+{
+       errcode_t retval;
+       __u32 crc;
+
+       if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+               EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+               return 0;
+
+       retval = ext2fs_ext_attr_block_csum(fs, inum, block, hdr, &crc);
+       if (retval)
+               return retval;
+       hdr->h_checksum = ext2fs_cpu_to_le32(crc);
+       return 0;
+}
+
 static __u16 do_nothing16(__u16 x)
 {
        return x;

diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in
index 430d567..90be193 100644 (file)
--- a/lib/ext2fs/ext2_err.et.in
+++ b/lib/ext2fs/ext2_err.et.in
@@ -461,4 +461,7 @@ ec  EXT2_ET_DIR_NO_SPACE_FOR_CSUM,
 ec     EXT2_ET_DIR_CSUM_INVALID,
        "Directory block checksum does not match directory block"
 
+ec     EXT2_ET_EXT_ATTR_CSUM_INVALID,
+       "Extended attribute block checksum does not match block"
+
        end

diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index cc47399..b793885 100644 (file)
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -943,6 +943,12 @@ 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_ext_attr_block_csum_set(ext2_filsys fs,
+                                       ext2_ino_t inum, blk64_t block,
+                                       struct ext2_ext_attr_header *hdr);
+extern int ext2fs_ext_attr_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
+                                            blk64_t block,
+                                            struct ext2_ext_attr_header *hdr);
 #define EXT2_DIRENT_TAIL(block, blocksize) \
        ((struct ext2_dir_entry_tail *)(((void *)(block)) + \
        (blocksize) - sizeof(struct ext2_dir_entry_tail)))
@@ -1097,16 +1103,24 @@ extern __u32 ext2fs_ext_attr_hash_entry(struct ext2_ext_attr_entry *entry,
 extern errcode_t ext2fs_read_ext_attr(ext2_filsys fs, blk_t block, void *buf);
 extern errcode_t ext2fs_read_ext_attr2(ext2_filsys fs, blk64_t block,
                                       void *buf);
+extern errcode_t ext2fs_read_ext_attr3(ext2_filsys fs, blk64_t block,
+                                      void *buf, ext2_ino_t inum);
 extern errcode_t ext2fs_write_ext_attr(ext2_filsys fs, blk_t block,
                                       void *buf);
 extern errcode_t ext2fs_write_ext_attr2(ext2_filsys fs, blk64_t block,
                                       void *buf);
+extern errcode_t ext2fs_write_ext_attr3(ext2_filsys fs, blk64_t block,
+                                      void *buf, ext2_ino_t inum);
 extern errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk,
                                           char *block_buf,
                                           int adjust, __u32 *newcount);
 extern errcode_t ext2fs_adjust_ea_refcount2(ext2_filsys fs, blk64_t blk,
                                           char *block_buf,
                                           int adjust, __u32 *newcount);
+extern errcode_t ext2fs_adjust_ea_refcount3(ext2_filsys fs, blk64_t blk,
+                                          char *block_buf,
+                                          int adjust, __u32 *newcount,
+                                          ext2_ino_t inum);
 
 /* extent.c */
 extern errcode_t ext2fs_extent_header_verify(void *ptr, int size);

diff --git a/lib/ext2fs/ext_attr.c b/lib/ext2fs/ext_attr.c
index 1889824..9649a14 100644 (file)
--- a/lib/ext2fs/ext_attr.c
+++ b/lib/ext2fs/ext_attr.c
@@ -61,17 +61,29 @@ __u32 ext2fs_ext_attr_hash_entry(struct ext2_ext_attr_entry *entry, void *data)
 #undef NAME_HASH_SHIFT
 #undef VALUE_HASH_SHIFT
 
-errcode_t ext2fs_read_ext_attr2(ext2_filsys fs, blk64_t block, void *buf)
+errcode_t ext2fs_read_ext_attr3(ext2_filsys fs, blk64_t block, void *buf,
+                               ext2_ino_t inum)
 {
        errcode_t       retval;
 
        retval = io_channel_read_blk64(fs->io, block, 1, buf);
        if (retval)
                return retval;
+
+       if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
+           !ext2fs_ext_attr_block_csum_verify(fs, inum, block, buf))
+               retval = EXT2_ET_EXT_ATTR_CSUM_INVALID;
+
 #ifdef WORDS_BIGENDIAN
        ext2fs_swap_ext_attr(buf, buf, fs->blocksize, 1);
 #endif
-       return 0;
+
+       return retval;
+}
+
+errcode_t ext2fs_read_ext_attr2(ext2_filsys fs, blk64_t block, void *buf)
+{
+       return ext2fs_read_ext_attr3(fs, block, buf, 0);
 }
 
 errcode_t ext2fs_read_ext_attr(ext2_filsys fs, blk_t block, void *buf)
@@ -79,30 +91,40 @@ errcode_t ext2fs_read_ext_attr(ext2_filsys fs, blk_t block, void *buf)
        return ext2fs_read_ext_attr2(fs, block, buf);
 }
 
-errcode_t ext2fs_write_ext_attr2(ext2_filsys fs, blk64_t block, void *inbuf)
+errcode_t ext2fs_write_ext_attr3(ext2_filsys fs, blk64_t block, void *inbuf,
+                                ext2_ino_t inum)
 {
        errcode_t       retval;
        char            *write_buf;
-#ifdef WORDS_BIGENDIAN
-       char            *buf = NULL;
 
-       retval = ext2fs_get_mem(fs->blocksize, &buf);
+#ifdef WORDS_BIGENDIAN
+       retval = ext2fs_get_mem(fs->blocksize, &write_buf);
        if (retval)
                return retval;
-       write_buf = buf;
-       ext2fs_swap_ext_attr(buf, inbuf, fs->blocksize, 1);
+       ext2fs_swap_ext_attr(write_buf, inbuf, fs->blocksize, 1);
 #else
        write_buf = (char *) inbuf;
 #endif
+
+       retval = ext2fs_ext_attr_block_csum_set(fs, inum, block,
+                       (struct ext2_ext_attr_header *)write_buf);
+       if (retval)
+               return retval;
+
        retval = io_channel_write_blk64(fs->io, block, 1, write_buf);
 #ifdef WORDS_BIGENDIAN
-       ext2fs_free_mem(&buf);
+       ext2fs_free_mem(&write_buf);
 #endif
        if (!retval)
                ext2fs_mark_changed(fs);
        return retval;
 }
 
+errcode_t ext2fs_write_ext_attr2(ext2_filsys fs, blk64_t block, void *inbuf)
+{
+       return ext2fs_write_ext_attr3(fs, block, inbuf, 0);
+}
+
 errcode_t ext2fs_write_ext_attr(ext2_filsys fs, blk_t block, void *inbuf)
 {
        return ext2fs_write_ext_attr2(fs, block, inbuf);
@@ -111,9 +133,9 @@ errcode_t ext2fs_write_ext_attr(ext2_filsys fs, blk_t block, void *inbuf)
 /*
  * This function adjusts the reference count of the EA block.
  */
-errcode_t ext2fs_adjust_ea_refcount2(ext2_filsys fs, blk64_t blk,
+errcode_t ext2fs_adjust_ea_refcount3(ext2_filsys fs, blk64_t blk,
                                    char *block_buf, int adjust,
-                                   __u32 *newcount)
+                                   __u32 *newcount, ext2_ino_t inum)
 {
        errcode_t       retval;
        struct ext2_ext_attr_header *header;
@@ -130,7 +152,7 @@ errcode_t ext2fs_adjust_ea_refcount2(ext2_filsys fs, blk64_t blk,
                block_buf = buf;
        }
 
-       retval = ext2fs_read_ext_attr2(fs, blk, block_buf);
+       retval = ext2fs_read_ext_attr3(fs, blk, block_buf, inum);
        if (retval)
                goto errout;
 
@@ -139,7 +161,7 @@ errcode_t ext2fs_adjust_ea_refcount2(ext2_filsys fs, blk64_t blk,
        if (newcount)
                *newcount = header->h_refcount;
 
-       retval = ext2fs_write_ext_attr2(fs, blk, block_buf);
+       retval = ext2fs_write_ext_attr3(fs, blk, block_buf, inum);
        if (retval)
                goto errout;
 
@@ -149,9 +171,18 @@ errout:
        return retval;
 }
 
+errcode_t ext2fs_adjust_ea_refcount2(ext2_filsys fs, blk64_t blk,
+                                   char *block_buf, int adjust,
+                                   __u32 *newcount)
+{
+       return ext2fs_adjust_ea_refcount3(fs, blk, block_buf, adjust,
+                                         newcount, 0);
+}
+
 errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk,
                                        char *block_buf, int adjust,
                                        __u32 *newcount)
 {
-       return ext2fs_adjust_ea_refcount(fs, blk, block_buf, adjust, newcount);
+       return ext2fs_adjust_ea_refcount2(fs, blk, block_buf, adjust,
+                                         newcount);
 }

diff --git a/lib/ext2fs/swapfs.c b/lib/ext2fs/swapfs.c
index 69916e5..de178a4 100644 (file)
--- a/lib/ext2fs/swapfs.c
+++ b/lib/ext2fs/swapfs.c
@@ -157,7 +157,8 @@ void ext2fs_swap_ext_attr_header(struct ext2_ext_attr_header *to_header,
        to_header->h_blocks   = ext2fs_swab32(from_header->h_blocks);
        to_header->h_refcount = ext2fs_swab32(from_header->h_refcount);
        to_header->h_hash     = ext2fs_swab32(from_header->h_hash);
-       for (n = 0; n < 4; n++)
+       to_header->h_checksum = ext2fs_swab32(from_header->h_checksum);
+       for (n = 0; n < 3; n++)
                to_header->h_reserved[n] =
                        ext2fs_swab32(from_header->h_reserved[n]);
 }