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

BugLink: https://bugs.launchpad.net/bugs/1787281
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>
(cherry picked from commit 14cb2c8a6c5dae57ee3e2da10fa3db2b9087e39e)
Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/block/partitions/aix.c b/block/partitions/aix.c
index 007f95eea0e1a9b6b79751ce6f109d151daa12f4..850cbd1860d4caea26d1fb861bc5f526744c6666 100644 (file)
--- 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);