partitions/aix: fix usage of uninitialized lv_info and lvname structures

The if-block that sets a successful return value in aix_partition()
uses 'lvip[].pps_per_lv' and 'n[].name' potentially uninitialized.

For example, if 'numlvs' is zero or alloc_lvn() fails, neither is
initialized, but are used anyway if alloc_pvd() succeeds after it.

So, make the alloc_pvd() call conditional on their initialization.

This has been hit when attaching an apparently corrupted/stressed
AIX LUN, misleading the kernel to pr_warn() invalid data and hang.

    [...] partition (null) (11 pp's found) is not contiguous
    [...] partition (null) (2 pp's found) is not contiguous
    [...] partition (null) (3 pp's found) is not contiguous
    [...] partition (null) (64 pp's found) is not contiguous

Fixes: 6ceea22bbbc8 ("partitions: add aix lvm partition support files")
Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 3 insertions, 2 deletions

diff --git a/block/partitions/aix.c b/block/partitions/aix.c
index 007f95eea0e1..850cbd1860d4 100644
--- a/block/partitions/aix.c
+++ b/block/partitions/aix.c
@@ -178,7 +178,7 @@ int aix_partition(struct parsed_partitions *state)
         u32 vgda_sector = 0;
         u32 vgda_len = 0;
         int numlvs = 0;
-        struct pvd *pvd;
+        struct pvd *pvd = NULL;
         struct lv_info {
                 unsigned short pps_per_lv;
                 unsigned short pps_found;
@@ -232,10 +232,11 @@ int aix_partition(struct parsed_partitions *state)
                                 if (lvip[i].pps_per_lv)
                                         foundlvs += 1;
                         }
+                        /* pvd loops depend on n[].name and lvip[].pps_per_lv */
+                        pvd = alloc_pvd(state, vgda_sector + 17);
                 }
                 put_dev_sector(sect);
         }
-        pvd = alloc_pvd(state, vgda_sector + 17);
         if (pvd) {
                 int numpps = be16_to_cpu(pvd->pp_count);
                 int psn_part1 = be32_to_cpu(pvd->psn_part1);