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Merge pull request #22442 from DaanDeMeyer/fix-entry-iteration

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journal: Fix entry array iteration in case of corruption
This commit is contained in:
Lennart Poettering 2022-02-08 14:29:24 +01:00 committed by GitHub
commit 9eb0583feb
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1 changed files with 57 additions and 1 deletions
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58
src/libsystemd/sd-journal/journal-file.c
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@ -2163,6 +2163,41 @@ static int bump_array_index(uint64_t *i, direction_t direction, uint64_t n) {
return 1;
}
static int bump_entry_array(JournalFile *f, Object *o, uint64_t offset, uint64_t first, direction_t direction, uint64_t *ret) {
uint64_t p, q = 0;
int r;
assert(f);
assert(offset);
assert(ret);
if (direction == DIRECTION_DOWN)
return le64toh(o->entry_array.next_entry_array_offset);
/* Entry array chains are a singly linked list, so to find the previous array in the chain, we have
* to start iterating from the top. */
p = first;
while (p > 0 && p != offset) {
r = journal_file_move_to_object(f, OBJECT_ENTRY_ARRAY, p, &o);
if (r < 0)
return r;
q = p;
p = le64toh(o->entry_array.next_entry_array_offset);
}
/* If we can't find the previous entry array in the entry array chain, we're likely dealing with a
* corrupted journal file. */
if (p == 0)
return -EBADMSG;
*ret = q;
return 0;
}
static int generic_array_get(
JournalFile *f,
uint64_t first,
@ -2189,6 +2224,24 @@ static int generic_array_get(
while (a > 0) {
r = journal_file_move_to_object(f, OBJECT_ENTRY_ARRAY, a, &o);
if (IN_SET(r, -EBADMSG, -EADDRNOTAVAIL)) {
/* If there's corruption and we're going downwards, let's pretend we reached the
* final entry in the entry array chain. */
if (direction == DIRECTION_DOWN)
return 0;
/* If there's corruption and we're going upwards, move back to the previous entry
* array and start iterating entries from there. */
r = bump_entry_array(f, NULL, a, first, DIRECTION_UP, &a);
if (r < 0)
return r;
i = UINT64_MAX;
break;
}
if (r < 0)
return r;
@ -2240,8 +2293,11 @@ static int generic_array_get(
log_debug_errno(r, "Entry item %" PRIu64 " is bad, skipping over it.", i);
} while (bump_array_index(&i, direction, k) > 0);
r = bump_entry_array(f, o, a, first, direction, &a);
if (r < 0)
return r;
t += k;
a = le64toh(o->entry_array.next_entry_array_offset);
i = UINT64_MAX;
}