xfs_db: check for valid inode data pointer before dereferencing

When processing an inode, the code checks various flags to determine
whether to output messages or not. When checking the CLI provided
inode numbers to be verbose about, we fail to check if the inode
data structre returned is valid or not before dereferencing it.
Hence running xfs_check with the "serious errors only" flag, xfs_db
will crash. Fix up the "should we output" logic to be safe.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/db/check.c b/db/check.c
index c62321b51e49863ad5beca41901a2f08ba2a962d..4f8a62a7b5c3a055b57405e93c715cc3d786eb3e 100644 (file)
--- a/db/check.c
+++ b/db/check.c
@@ -2619,6 +2619,7 @@ process_inode(
        xfs_qcnt_t              ic = 0;
        xfs_qcnt_t              rc = 0;
        xfs_dqid_t              dqprid;
+       int                     v = 0;
        static char             okfmts[] = {
                0,                              /* type 0 unused */
                1 << XFS_DINODE_FMT_DEV,        /* FIFO */
@@ -2653,15 +2654,16 @@ process_inode(
                bno = XFS_INO_TO_FSB(mp, ino);
                blkmap = NULL;
        }
+       v = (!sflag || (id && id->ilist) || CHECK_BLIST(bno));
        if (idic.di_magic != XFS_DINODE_MAGIC) {
-               if (!sflag || isfree || id->ilist || CHECK_BLIST(bno))
+               if (isfree || v)
                        dbprintf(_("bad magic number %#x for inode %lld\n"),
                                idic.di_magic, ino);
                error++;
                return;
        }
        if (!XFS_DINODE_GOOD_VERSION(idic.di_version)) {
-               if (!sflag || isfree || id->ilist || CHECK_BLIST(bno))
+               if (isfree || v)
                        dbprintf(_("bad version number %#x for inode %lld\n"),
                                idic.di_version, ino);
                error++;
@@ -2669,7 +2671,7 @@ process_inode(
        }
        if (isfree) {
                if (idic.di_nblocks != 0) {
-                       if (!sflag || id->ilist || CHECK_BLIST(bno))
+                       if (v)
                                dbprintf(_("bad nblocks %lld for free inode "
                                         "%lld\n"),
                                        idic.di_nblocks, ino);
@@ -2680,21 +2682,22 @@ process_inode(
                else
                        nlink = idic.di_nlink;
                if (nlink != 0) {
-                       if (!sflag || id->ilist || CHECK_BLIST(bno))
+                       if (v)
                                dbprintf(_("bad nlink %d for free inode %lld\n"),
                                        nlink, ino);
                        error++;
                }
                if (idic.di_mode != 0) {
-                       if (!sflag || id->ilist || CHECK_BLIST(bno))
+                       if (v)
                                dbprintf(_("bad mode %#o for free inode %lld\n"),
                                        idic.di_mode, ino);
                        error++;
                }
                return;
        }
+
        if (be32_to_cpu(dip->di_next_unlinked) != NULLAGINO) {
-               if (!sflag || isfree || id->ilist || CHECK_BLIST(bno))
+               if (v)
                        dbprintf(_("bad next unlinked %#x for inode %lld\n"),
                                be32_to_cpu(dip->di_next_unlinked), ino);
                error++;
@@ -2704,27 +2707,27 @@ process_inode(
         */
        if ((((idic.di_mode & S_IFMT) >> 12) > 15) ||
            (!(okfmts[(idic.di_mode & S_IFMT) >> 12] & (1 << idic.di_format)))) {
-               if (!sflag || id->ilist || CHECK_BLIST(bno))
+               if (v)
                        dbprintf(_("bad format %d for inode %lld type %#o\n"),
                                idic.di_format, id->ino, idic.di_mode & S_IFMT);
                error++;
                return;
        }
        if ((unsigned int)XFS_DFORK_ASIZE(dip, mp) >= XFS_LITINO(mp))  {
-               if (!sflag || id->ilist)
+               if (v)
                        dbprintf(_("bad fork offset %d for inode %lld\n"),
                                idic.di_forkoff, id->ino);
                error++;
                return;
        }
        if ((unsigned int)idic.di_aformat > XFS_DINODE_FMT_BTREE)  {
-               if (!sflag || id->ilist)
+               if (v)
                        dbprintf(_("bad attribute format %d for inode %lld\n"),
                                idic.di_aformat, id->ino);
                error++;
                return;
        }
-       if (verbose || id->ilist || CHECK_BLIST(bno))
+       if (verbose || (id && id->ilist) || CHECK_BLIST(bno))
                dbprintf(_("inode %lld mode %#o fmt %s "
                         "afmt %s "
                         "nex %d anex %d nblk %lld sz %lld%s%s%s%s%s%s%s\n"),
@@ -2844,20 +2847,20 @@ process_inode(
        }
        totblocks = totdblocks + totiblocks + atotdblocks + atotiblocks;
        if (totblocks != idic.di_nblocks) {
-               if (!sflag || id->ilist || CHECK_BLIST(bno))
+               if (v)
                        dbprintf(_("bad nblocks %lld for inode %lld, counted "
                                 "%lld\n"),
                                idic.di_nblocks, id->ino, totblocks);
                error++;
        }
        if (nextents != idic.di_nextents) {
-               if (!sflag || id->ilist || CHECK_BLIST(bno))
+               if (v)
                        dbprintf(_("bad nextents %d for inode %lld, counted %d\n"),
                                idic.di_nextents, id->ino, nextents);
                error++;
        }
        if (anextents != idic.di_anextents) {
-               if (!sflag || id->ilist || CHECK_BLIST(bno))
+               if (v)
                        dbprintf(_("bad anextents %d for inode %lld, counted "
                                 "%d\n"),
                                idic.di_anextents, id->ino, anextents);