If an agf has bad values in the freelist, this can wreak
havoc if, for example, first > last and the loop
never exits; we index agfl->agfl_bno[i] off into the weeds.
If they're off, warn about it and skip the scan.
Thisis done both in xfs_check and xfs_db's freespace cmd.
Also fix uninit'd variable "i" from previous, similar fix
for xfs_repair.
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---
diff --git a/db/check.c b/db/check.c
index e601e0a..35325b7 100644
--- a/db/check.c
+++ b/db/check.c
@@ -4112,6 +4112,16 @@ scan_freelist(
return;
}
i = be32_to_cpu(agf->agf_flfirst);
+
+ /* verify agf values before proceeding */
+ if (be32_to_cpu(agf->agf_flfirst) >= XFS_AGFL_SIZE(mp) ||
+ be32_to_cpu(agf->agf_fllast) >= XFS_AGFL_SIZE(mp)) {
+ dbprintf(_("agf %d freelist blocks bad, skipping "
+ "freelist scan\n"), i);
+ pop_cur();
+ return;
+ }
+
count = 0;
for (;;) {
bno = be32_to_cpu(agfl->agfl_bno[i]);
diff --git a/db/freesp.c b/db/freesp.c
index c4dabad..472b1f7 100644
--- a/db/freesp.c
+++ b/db/freesp.c
@@ -239,6 +239,16 @@ scan_freelist(
XFS_FSS_TO_BB(mp, 1), DB_RING_IGN, NULL);
agfl = iocur_top->data;
i = be32_to_cpu(agf->agf_flfirst);
+
+ /* verify agf values before proceeding */
+ if (be32_to_cpu(agf->agf_flfirst) >= XFS_AGFL_SIZE(mp) ||
+ be32_to_cpu(agf->agf_fllast) >= XFS_AGFL_SIZE(mp)) {
+ dbprintf(_("agf %d freelist blocks bad, skipping "
+ "freelist scan\n"), i);
+ pop_cur();
+ return;
+ }
+
for (;;) {
bno = be32_to_cpu(agfl->agfl_bno[i]);
addtohist(seqno, bno, 1);
diff --git a/repair/scan.c b/repair/scan.c
index 1d39bdc..6a62dff 100644
--- a/repair/scan.c
+++ b/repair/scan.c
@@ -1066,6 +1066,7 @@ scan_freelist(
return;
}
agfl = XFS_BUF_TO_AGFL(agflbuf);
+ i = be32_to_cpu(agf->agf_flfirst);
if (no_modify) {
/* agf values not fixed in verify_set_agf, so recheck */
@@ -1078,7 +1079,6 @@ scan_freelist(
} else /* should have been fixed in verify_set_agf() */
ASSERT(0);
- i = be32_to_cpu(agf->agf_flfirst);
count = 0;
for (;;) {
bno = be32_to_cpu(agfl->agfl_bno[i]);
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