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journal: Stop comparing hash values from entry items against data objects

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These checks don't achieve anything of value. Assuming they were added to
check for corruption, they don't actually achieve this goal since other parts
of the data object can still get corrupted and we wouldn't notice unless we'd
recalculate the hash every time.

In theory, we could use the entry item hash to avoid a random access lookup
for the data object hash in the journal file in the future to speed up searching,
but for finding all entry objects containing a specific data objects, we already
have entry arrays per data object to get fast access to this information.

This means that duplicating the hashes in the entry item doesn't result in any
added value. In this commit, we remove the checks so that in future commits we
can remove the hashes from the journal file format in the new compact mode.
This commit is contained in:
Daan De Meyer
2021-11-01 14:33:08 +00:00
parent c710944c83
commit 8bad545354
3 changed files with 2 additions and 27 deletions
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5
src/libsystemd/sd-journal/journal-file.c
View File

@@ -3565,21 +3565,16 @@ int journal_file_copy_entry(JournalFile *from, JournalFile *to, Object *o, uint6
for (uint64_t i = 0; i < n; i++) {
uint64_t l, h;
le64_t le_hash;
size_t t;
void *data;
Object *u;
q = le64toh(o->entry.items[i].object_offset);
le_hash = o->entry.items[i].hash;
r = journal_file_move_to_object(from, OBJECT_DATA, q, &o);
if (r < 0)
return r;
if (le_hash != o->data.hash)
return -EBADMSG;
l = le64toh(READ_NOW(o->object.size));
if (l < offsetof(Object, data.payload))
return -EBADMSG;

10
src/libsystemd/sd-journal/journal-verify.c
View File

@@ -645,11 +645,10 @@ static int verify_entry(
n = journal_file_entry_n_items(o);
for (i = 0; i < n; i++) {
uint64_t q, h;
uint64_t q;
Object *u;
q = le64toh(o->entry.items[i].object_offset);
h = le64toh(o->entry.items[i].hash);
if (!contains_uint64(cache_data_fd, n_data, q)) {
error(p, "Invalid data object of entry");
@@ -660,12 +659,7 @@ static int verify_entry(
if (r < 0)
return r;
if (le64toh(u->data.hash) != h) {
error(p, "Hash mismatch for data object of entry");
return -EBADMSG;
}
r = data_object_in_hash_table(f, h, q);
r = data_object_in_hash_table(f, le64toh(u->data.hash), q);
if (r < 0)
return r;
if (r == 0) {

14
src/libsystemd/sd-journal/sd-journal.c
View File

@@ -2303,12 +2303,10 @@ _public_ int sd_journal_get_data(sd_journal *j, const char *field, const void **
for (i = 0; i < n; i++) {
Object *d;
uint64_t p, l;
le64_t le_hash;
size_t t;
int compression;
p = le64toh(o->entry.items[i].object_offset);
le_hash = o->entry.items[i].hash;
r = journal_file_move_to_object(f, OBJECT_DATA, p, &d);
if (IN_SET(r, -EADDRNOTAVAIL, -EBADMSG)) {
log_debug_errno(r, "Entry item %"PRIu64" data object is bad, skipping over it: %m", i);
@@ -2317,11 +2315,6 @@ _public_ int sd_journal_get_data(sd_journal *j, const char *field, const void **
if (r < 0)
return r;
if (le_hash != d->data.hash) {
log_debug("Entry item %"PRIu64" hash is bad, skipping over it.", i);
continue;
}
l = le64toh(d->object.size) - offsetof(Object, data.payload);
compression = d->object.flags & OBJECT_COMPRESSION_MASK;
@@ -2450,10 +2443,8 @@ _public_ int sd_journal_enumerate_data(sd_journal *j, const void **data, size_t
for (uint64_t n = journal_file_entry_n_items(o); j->current_field < n; j->current_field++) {
uint64_t p;
le64_t le_hash;
p = le64toh(o->entry.items[j->current_field].object_offset);
le_hash = o->entry.items[j->current_field].hash;
r = journal_file_move_to_object(f, OBJECT_DATA, p, &o);
if (IN_SET(r, -EADDRNOTAVAIL, -EBADMSG)) {
log_debug_errno(r, "Entry item %"PRIu64" data object is bad, skipping over it: %m", j->current_field);
@@ -2462,11 +2453,6 @@ _public_ int sd_journal_enumerate_data(sd_journal *j, const void **data, size_t
if (r < 0)
return r;
if (le_hash != o->data.hash) {
log_debug("Entry item %"PRIu64" hash is bad, skipping over it.", j->current_field);
continue;
}
r = return_data(j, f, o, data, size);
if (r == -EBADMSG) {
log_debug("Entry item %"PRIu64" data payload is bad, skipping over it.", j->current_field);