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e2fsck: verify s_desc_size is power-of-two value 

Add a LOG2_CHECK mode for check_super_value() so that it is easy
to verify values that are supposed to be power-of-two values
(s_desc_size and s_inode_size so far).  In ext2fs_check_desc()
also check for a power-of-two s_desc_size.

Print out s_desc_size in debugfs "stats" and dumpe2fs output, if
it is non-zero.

It turns out that the s_desc_size validation in check_super_block()
is not currently used by e2fsck, because the group descriptors are
verified earlier by ext2fs_check_desc(), and even without an
explicit check of s_desc_size the group descriptors fail to align
correctly on disk.  It makes sense to keep the check_super_block()
regardless, in case the code changes at some point in the future.

Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
debian-1.42.9
Andreas Dilger 2013-12-23 16:03:41 -05:00 committed by Theodore Ts'o
parent fd5e00e1d0
commit 11d1116a7c
5 changed files with 15 additions and 12 deletions
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18
e2fsck/super.c
View File

@ -22,6 +22,7 @@
#define MIN_CHECK 1
#define MAX_CHECK 2
#define LOG2_CHECK 4
static void check_super_value(e2fsck_t ctx, const char *descr,
unsigned long value, int flags,
@ -30,7 +31,8 @@ static void check_super_value(e2fsck_t ctx, const char *descr,
struct problem_context pctx;
if (((flags & MIN_CHECK) && (value < min_val)) ||
((flags & MAX_CHECK) && (value > max_val))) {
((flags & MAX_CHECK) && (value > max_val)) ||
((flags & LOG2_CHECK) && (value & (value - 1) != 0))) {
clear_problem_context(&pctx);
pctx.num = value;
pctx.str = descr;
@ -527,14 +529,17 @@ void check_super_block(e2fsck_t ctx)
MAX_CHECK, 0, ext2fs_blocks_count(sb) / 2);
check_super_value(ctx, "reserved_gdt_blocks",
sb->s_reserved_gdt_blocks, MAX_CHECK, 0,
fs->blocksize/4);
fs->blocksize / sizeof(__u32));
check_super_value(ctx, "desc_size",
sb->s_desc_size, MAX_CHECK | LOG2_CHECK, 0,
EXT2_MAX_DESC_SIZE);
if (sb->s_rev_level > EXT2_GOOD_OLD_REV)
check_super_value(ctx, "first_ino", sb->s_first_ino,
MIN_CHECK | MAX_CHECK,
EXT2_GOOD_OLD_FIRST_INO, sb->s_inodes_count);
inode_size = EXT2_INODE_SIZE(sb);
check_super_value(ctx, "inode_size",
inode_size, MIN_CHECK | MAX_CHECK,
inode_size, MIN_CHECK | MAX_CHECK | LOG2_CHECK,
EXT2_GOOD_OLD_INODE_SIZE, fs->blocksize);
if (sb->s_blocks_per_group != (sb->s_clusters_per_group *
EXT2FS_CLUSTER_RATIO(fs))) {
@ -544,13 +549,6 @@ void check_super_block(e2fsck_t ctx)
ctx->flags |= E2F_FLAG_ABORT; /* never get here! */
return;
}
if (inode_size & (inode_size - 1)) {
pctx.num = inode_size;
pctx.str = "inode_size";
fix_problem(ctx, PR_0_MISC_CORRUPT_SUPER, &pctx);
ctx->flags |= E2F_FLAG_ABORT; /* never get here! */
return;
}
if ((ctx->flags & E2F_FLAG_GOT_DEVSIZE) &&
(ctx->num_blocks < ext2fs_blocks_count(sb))) {

2
lib/e2p/ls.c
View File

@ -259,6 +259,8 @@ void list_super2(struct ext2_super_block * sb, FILE *f)
else
fprintf(f, "Fragment size: %u\n",
EXT2_CLUSTER_SIZE(sb));
if (sb->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT)
fprintf(f, "Group descriptor size: %u\n", sb->s_desc_size);
if (sb->s_reserved_gdt_blocks)
fprintf(f, "Reserved GDT blocks: %u\n",
sb->s_reserved_gdt_blocks);

3
lib/ext2fs/check_desc.c
View File

@ -42,6 +42,9 @@ errcode_t ext2fs_check_desc(ext2_filsys fs)
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
if (EXT2_DESC_SIZE(fs->super) & (EXT2_DESC_SIZE(fs->super) - 1))
return EXT2_ET_BAD_DESC_SIZE;
retval = ext2fs_allocate_subcluster_bitmap(fs, "check_desc map", &bmap);
if (retval)
return retval;

2
lib/ext2fs/closefs.c
View File

@ -302,7 +302,7 @@ errcode_t ext2fs_flush2(ext2_filsys fs, int flags)
fs->desc_blocks);
/* swap the group descriptors */
for (j=0; j < fs->group_desc_count; j++) {
for (j = 0; j < fs->group_desc_count; j++) {
gdp = ext2fs_group_desc(fs, group_shadow, j);
ext2fs_swap_group_desc2(fs, gdp);
}

2
lib/ext2fs/ext2_fs.h
View File

@ -159,7 +159,7 @@ struct ext2_group_desc
__u16 bg_block_bitmap_csum_lo;/* crc32c(s_uuid+grp_num+bitmap) LSB */
__u16 bg_inode_bitmap_csum_lo;/* crc32c(s_uuid+grp_num+bitmap) LSB */
__u16 bg_itable_unused; /* Unused inodes count */
__u16 bg_checksum; /* crc16(s_uuid+grouo_num+group_desc)*/
__u16 bg_checksum; /* crc16(s_uuid+group_num+group_desc)*/
};
/*