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xfs: verify dir2 block format buffers 

Add a dir2 block format read verifier. To fully verify every block
when read, call xfs_dir2_data_check() on them. Change
xfs_dir2_data_check() to do runtime checking, convert ASSERT()
checks to XFS_WANT_CORRUPTED_RETURN(), which will trigger an ASSERT
failure on debug kernels, but on production kernels will dump an
error to dmesg and return EFSCORRUPTED to the caller.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Phil White <pwhite@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
This commit is contained in:
Dave Chinner 2012-11-12 22:54:12 +11:00 committed by Ben Myers
parent 20f7e9f372
commit 82025d7f79
3 changed files with 68 additions and 31 deletions
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22
fs/xfs/xfs_dir2_block.c
View File

@ -56,6 +56,26 @@ xfs_dir_startup(void)
xfs_dir_hash_dotdot = xfs_da_hashname((unsigned char *)"..", 2);
}
static void
xfs_dir2_block_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_target->bt_mount;
struct xfs_dir2_data_hdr *hdr = bp->b_addr;
int block_ok = 0;
block_ok = hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC);
block_ok = block_ok && __xfs_dir2_data_check(NULL, bp) == 0;
if (!block_ok) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, hdr);
xfs_buf_ioerror(bp, EFSCORRUPTED);
}
bp->b_iodone = NULL;
xfs_buf_ioend(bp, 0);
}
static int
xfs_dir2_block_read(
struct xfs_trans *tp,
@ -65,7 +85,7 @@ xfs_dir2_block_read(
struct xfs_mount *mp = dp->i_mount;
return xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, bpp,
XFS_DATA_FORK, NULL);
XFS_DATA_FORK, xfs_dir2_block_verify);
}
static void

73
fs/xfs/xfs_dir2_data.c
View File

@ -34,14 +34,13 @@
STATIC xfs_dir2_data_free_t *
xfs_dir2_data_freefind(xfs_dir2_data_hdr_t *hdr, xfs_dir2_data_unused_t *dup);
#ifdef DEBUG
/*
* Check the consistency of the data block.
* The input can also be a block-format directory.
* Pop an assert if we find anything bad.
* Return 0 is the buffer is good, otherwise an error.
*/
void
xfs_dir2_data_check(
int
__xfs_dir2_data_check(
struct xfs_inode *dp, /* incore inode pointer */
struct xfs_buf *bp) /* data block's buffer */
{
@ -64,18 +63,23 @@ xfs_dir2_data_check(
int stale; /* count of stale leaves */
struct xfs_name name;
mp = dp->i_mount;
mp = bp->b_target->bt_mount;
hdr = bp->b_addr;
bf = hdr->bestfree;
p = (char *)(hdr + 1);
if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC)) {
switch (hdr->magic) {
case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
btp = xfs_dir2_block_tail_p(mp, hdr);
lep = xfs_dir2_block_leaf_p(btp);
endp = (char *)lep;
} else {
ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC));
break;
case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
endp = (char *)hdr + mp->m_dirblksize;
break;
default:
XFS_ERROR_REPORT("Bad Magic", XFS_ERRLEVEL_LOW, mp);
return EFSCORRUPTED;
}
count = lastfree = freeseen = 0;
@ -83,19 +87,22 @@ xfs_dir2_data_check(
* Account for zero bestfree entries.
*/
if (!bf[0].length) {
ASSERT(!bf[0].offset);
XFS_WANT_CORRUPTED_RETURN(!bf[0].offset);
freeseen |= 1 << 0;
}
if (!bf[1].length) {
ASSERT(!bf[1].offset);
XFS_WANT_CORRUPTED_RETURN(!bf[1].offset);
freeseen |= 1 << 1;
}
if (!bf[2].length) {
ASSERT(!bf[2].offset);
XFS_WANT_CORRUPTED_RETURN(!bf[2].offset);
freeseen |= 1 << 2;
}
ASSERT(be16_to_cpu(bf[0].length) >= be16_to_cpu(bf[1].length));
ASSERT(be16_to_cpu(bf[1].length) >= be16_to_cpu(bf[2].length));
XFS_WANT_CORRUPTED_RETURN(be16_to_cpu(bf[0].length) >=
be16_to_cpu(bf[1].length));
XFS_WANT_CORRUPTED_RETURN(be16_to_cpu(bf[1].length) >=
be16_to_cpu(bf[2].length));
/*
* Loop over the data/unused entries.
*/
@ -107,17 +114,20 @@ xfs_dir2_data_check(
* doesn't need to be there.
*/
if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
ASSERT(lastfree == 0);
ASSERT(be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) ==
(char *)dup - (char *)hdr);
XFS_WANT_CORRUPTED_RETURN(lastfree == 0);
XFS_WANT_CORRUPTED_RETURN(
be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) ==
(char *)dup - (char *)hdr);
dfp = xfs_dir2_data_freefind(hdr, dup);
if (dfp) {
i = (int)(dfp - bf);
ASSERT((freeseen & (1 << i)) == 0);
XFS_WANT_CORRUPTED_RETURN(
(freeseen & (1 << i)) == 0);
freeseen |= 1 << i;
} else {
ASSERT(be16_to_cpu(dup->length) <=
be16_to_cpu(bf[2].length));
XFS_WANT_CORRUPTED_RETURN(
be16_to_cpu(dup->length) <=
be16_to_cpu(bf[2].length));
}
p += be16_to_cpu(dup->length);
lastfree = 1;
@ -130,10 +140,12 @@ xfs_dir2_data_check(
* The linear search is crude but this is DEBUG code.
*/
dep = (xfs_dir2_data_entry_t *)p;
ASSERT(dep->namelen != 0);
ASSERT(xfs_dir_ino_validate(mp, be64_to_cpu(dep->inumber)) == 0);
ASSERT(be16_to_cpu(*xfs_dir2_data_entry_tag_p(dep)) ==
(char *)dep - (char *)hdr);
XFS_WANT_CORRUPTED_RETURN(dep->namelen != 0);
XFS_WANT_CORRUPTED_RETURN(
!xfs_dir_ino_validate(mp, be64_to_cpu(dep->inumber)));
XFS_WANT_CORRUPTED_RETURN(
be16_to_cpu(*xfs_dir2_data_entry_tag_p(dep)) ==
(char *)dep - (char *)hdr);
count++;
lastfree = 0;
if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC)) {
@ -148,27 +160,30 @@ xfs_dir2_data_check(
be32_to_cpu(lep[i].hashval) == hash)
break;
}
ASSERT(i < be32_to_cpu(btp->count));
XFS_WANT_CORRUPTED_RETURN(i < be32_to_cpu(btp->count));
}
p += xfs_dir2_data_entsize(dep->namelen);
}
/*
* Need to have seen all the entries and all the bestfree slots.
*/
ASSERT(freeseen == 7);
XFS_WANT_CORRUPTED_RETURN(freeseen == 7);
if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC)) {
for (i = stale = 0; i < be32_to_cpu(btp->count); i++) {
if (lep[i].address ==
cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
stale++;
if (i > 0)
ASSERT(be32_to_cpu(lep[i].hashval) >= be32_to_cpu(lep[i - 1].hashval));
XFS_WANT_CORRUPTED_RETURN(
be32_to_cpu(lep[i].hashval) >=
be32_to_cpu(lep[i - 1].hashval));
}
ASSERT(count == be32_to_cpu(btp->count) - be32_to_cpu(btp->stale));
ASSERT(stale == be32_to_cpu(btp->stale));
XFS_WANT_CORRUPTED_RETURN(count ==
be32_to_cpu(btp->count) - be32_to_cpu(btp->stale));
XFS_WANT_CORRUPTED_RETURN(stale == be32_to_cpu(btp->stale));
}
return 0;
}
#endif
/*
* Given a data block and an unused entry from that block,

4
fs/xfs/xfs_dir2_priv.h
View File

@ -41,10 +41,12 @@ extern int xfs_dir2_leaf_to_block(struct xfs_da_args *args,
/* xfs_dir2_data.c */
#ifdef DEBUG
extern void xfs_dir2_data_check(struct xfs_inode *dp, struct xfs_buf *bp);
#define xfs_dir2_data_check(dp,bp) __xfs_dir2_data_check(dp, bp);
#else
#define xfs_dir2_data_check(dp,bp)
#endif
extern int __xfs_dir2_data_check(struct xfs_inode *dp, struct xfs_buf *bp);
extern struct xfs_dir2_data_free *
xfs_dir2_data_freeinsert(struct xfs_dir2_data_hdr *hdr,
struct xfs_dir2_data_unused *dup, int *loghead);