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libext2fs: check EA block headers when reading in the block

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When reading an EA block in from disk, do a quick sanity check of the
block header, and return an error if we think we have garbage.  Teach
e2fsck to ignore the new error code in favor of doing its own
checking, and remove the strict_csums bits while we're at it.

(Also document some assumptions in the new ext_attr code.)

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Darrick J. Wong 2014-08-02 22:32:11 -04:00 committed by Theodore Ts'o
parent 3466e95f0d
commit 5b9cbd76df
4 changed files with 31 additions and 20 deletions
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18
e2fsck/pass1.c
View File

@ -1748,12 +1748,16 @@ static int check_ext_attr(e2fsck_t ctx, struct problem_context *pctx,
pctx->blk = blk;
pctx->errcode = ext2fs_read_ext_attr3(fs, blk, block_buf, pctx->ino);
if (pctx->errcode == EXT2_ET_EXT_ATTR_CSUM_INVALID) {
if (fix_problem(ctx, PR_1_EA_BLOCK_CSUM_INVALID, pctx))
goto clear_extattr;
pctx->errcode = 0;
failed_csum = 1;
}
if (pctx->errcode && fix_problem(ctx, PR_1_READ_EA_BLOCK, pctx))
} else if (pctx->errcode == EXT2_ET_BAD_EA_HEADER)
pctx->errcode = 0;
if (pctx->errcode &&
fix_problem(ctx, PR_1_READ_EA_BLOCK, pctx)) {
pctx->errcode = 0;
goto clear_extattr;
}
header = (struct ext2_ext_attr_header *) block_buf;
pctx->blk = ext2fs_file_acl_block(fs, inode);
if (((ctx->ext_attr_ver == 1) &&
@ -1769,6 +1773,9 @@ static int check_ext_attr(e2fsck_t ctx, struct problem_context *pctx,
goto clear_extattr;
}
if (pctx->errcode && fix_problem(ctx, PR_1_READ_EA_BLOCK, pctx))
goto clear_extattr;
region = region_create(0, fs->blocksize);
if (!region) {
fix_problem(ctx, PR_1_EA_ALLOC_REGION_ABORT, pctx);
@ -2438,8 +2445,7 @@ static void check_blocks(e2fsck_t ctx, struct problem_context *pctx,
}
}
if (ext2fs_file_acl_block(fs, inode) &&
check_ext_attr(ctx, pctx, block_buf)) {
if (check_ext_attr(ctx, pctx, block_buf)) {
if (ctx->flags & E2F_FLAG_SIGNAL_MASK)
goto out;
pb.num_blocks++;

5
e2fsck/problem.c
View File

@ -992,11 +992,6 @@ static struct e2fsck_problem problem_table[] = {
"extent\n\t(logical @b %c, @n physical @b %b, len %N)\n"),
PROMPT_FIX, 0 },
/* Inode extended attribute block checksum does not match block. */
{ PR_1_EA_BLOCK_CSUM_INVALID,
N_("@i %i @a @b %b checksum does not match block. "),
PROMPT_CLEAR, 0 },
/*
* Inode extended attribute block passes checks, but checksum does not
* match block.

3
e2fsck/problem.h
View File

@ -583,9 +583,6 @@ struct problem_context {
/* extent block passes checks, but checksum does not match extent block */
#define PR_1_EXTENT_ONLY_CSUM_INVALID 0x01006A
/* ea block checksum invalid */
#define PR_1_EA_BLOCK_CSUM_INVALID 0x01006B
/* ea block passes checks, but checksum invalid */
#define PR_1_EA_BLOCK_ONLY_CSUM_INVALID 0x01006C

25
lib/ext2fs/ext_attr.c
View File

@ -58,12 +58,23 @@ __u32 ext2fs_ext_attr_hash_entry(struct ext2_ext_attr_entry *entry, void *data)
return hash;
}
static errcode_t check_ext_attr_header(struct ext2_ext_attr_header *header)
{
if ((header->h_magic != EXT2_EXT_ATTR_MAGIC_v1 &&
header->h_magic != EXT2_EXT_ATTR_MAGIC) ||
header->h_blocks != 1)
return EXT2_ET_BAD_EA_HEADER;
return 0;
}
#undef NAME_HASH_SHIFT
#undef VALUE_HASH_SHIFT
errcode_t ext2fs_read_ext_attr3(ext2_filsys fs, blk64_t block, void *buf,
ext2_ino_t inum)
{
int csum_failed = 0;
errcode_t retval;
retval = io_channel_read_blk64(fs->io, block, 1, buf);
@ -72,12 +83,16 @@ errcode_t ext2fs_read_ext_attr3(ext2_filsys fs, blk64_t block, void *buf,
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;
csum_failed = 1;
#ifdef WORDS_BIGENDIAN
ext2fs_swap_ext_attr(buf, buf, fs->blocksize, 1);
#endif
retval = check_ext_attr_header(buf);
if (retval == 0 && csum_failed)
retval = EXT2_ET_EXT_ATTR_CSUM_INVALID;
return retval;
}
@ -321,6 +336,7 @@ errcode_t ext2fs_free_ext_attr(ext2_filsys fs, ext2_ino_t ino,
if (err)
goto out2;
/* We only know how to deal with v2 EA blocks */
header = (struct ext2_ext_attr_header *) block_buf;
if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
err = EXT2_ET_BAD_EA_HEADER;
@ -380,6 +396,7 @@ static errcode_t prep_ea_block_for_write(ext2_filsys fs, ext2_ino_t ino,
if (err)
goto out2;
/* We only know how to deal with v2 EA blocks */
header = (struct ext2_ext_attr_header *) block_buf;
if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
err = EXT2_ET_BAD_EA_HEADER;
@ -763,17 +780,13 @@ read_ea_block:
if (err)
goto out3;
/* We only know how to deal with v2 EA blocks */
header = (struct ext2_ext_attr_header *) block_buf;
if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
err = EXT2_ET_BAD_EA_HEADER;
goto out3;
}
if (header->h_blocks != 1) {
err = EXT2_ET_BAD_EA_HEADER;
goto out3;
}
/* Read EAs */
storage_size = handle->fs->blocksize -
sizeof(struct ext2_ext_attr_header);