linux-kernel - [PATCH v2] erofs: fix invalid unmapped accesses in z_erofs_fill_inode

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Date:   Wed,  5 Oct 2022 09:35:28 +0800
From:   Yue Hu <zbestahu@....com>
To:     xiang@...nel.org, chao@...nel.org
Cc:     linux-erofs@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        zhangwen@...lpad.com, Yue Hu <huyue2@...lpad.com>
Subject: [PATCH v2] erofs: fix invalid unmapped accesses in z_erofs_fill_inode_lazy()

From: Yue Hu <huyue2@...lpad.com>

Note that we are still accessing 'h_idata_size' and 'h_fragmentoff'
after calling erofs_put_metabuf(), that is not correct. Fix it.

Fixes: ab92184ff8f1 ("erofs: add on-disk compressed tail-packing inline support")
Fixes: b15b2e307c3a ("erofs: support on-disk compressed fragments data")
Signed-off-by: Yue Hu <huyue2@...lpad.com>
---
v2: refine the subject, jump label naming, code style (Xiang)

 fs/erofs/zmap.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 44c27ef39c43..0bb66927e3d0 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -57,8 +57,7 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 
 	pos = ALIGN(iloc(EROFS_SB(sb), vi->nid) + vi->inode_isize +
 		    vi->xattr_isize, 8);
-	kaddr = erofs_read_metabuf(&buf, sb, erofs_blknr(pos),
-				   EROFS_KMAP_ATOMIC);
+	kaddr = erofs_read_metabuf(&buf, sb, erofs_blknr(pos), EROFS_KMAP);
 	if (IS_ERR(kaddr)) {
 		err = PTR_ERR(kaddr);
 		goto out_unlock;
@@ -73,7 +72,7 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 		vi->z_advise = Z_EROFS_ADVISE_FRAGMENT_PCLUSTER;
 		vi->z_fragmentoff = le64_to_cpu(*(__le64 *)h) ^ (1ULL << 63);
 		vi->z_tailextent_headlcn = 0;
-		goto unmap_done;
+		goto done;
 	}
 	vi->z_advise = le16_to_cpu(h->h_advise);
 	vi->z_algorithmtype[0] = h->h_algorithmtype & 15;
@@ -85,7 +84,7 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 		erofs_err(sb, "unknown HEAD%u format %u for nid %llu, please upgrade kernel",
 			  headnr + 1, vi->z_algorithmtype[headnr], vi->nid);
 		err = -EOPNOTSUPP;
-		goto unmap_done;
+		goto out_put_metabuf;
 	}
 
 	vi->z_logical_clusterbits = LOG_BLOCK_SIZE + (h->h_clusterbits & 7);
@@ -95,7 +94,7 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 		erofs_err(sb, "per-inode big pcluster without sb feature for nid %llu",
 			  vi->nid);
 		err = -EFSCORRUPTED;
-		goto unmap_done;
+		goto out_put_metabuf;
 	}
 	if (vi->datalayout == EROFS_INODE_FLAT_COMPRESSION &&
 	    !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1) ^
@@ -103,12 +102,8 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 		erofs_err(sb, "big pcluster head1/2 of compact indexes should be consistent for nid %llu",
 			  vi->nid);
 		err = -EFSCORRUPTED;
-		goto unmap_done;
+		goto out_put_metabuf;
 	}
-unmap_done:
-	erofs_put_metabuf(&buf);
-	if (err)
-		goto out_unlock;
 
 	if (vi->z_advise & Z_EROFS_ADVISE_INLINE_PCLUSTER) {
 		struct erofs_map_blocks map = {
@@ -127,7 +122,7 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 			err = -EFSCORRUPTED;
 		}
 		if (err < 0)
-			goto out_unlock;
+			goto out_put_metabuf;
 	}
 
 	if (vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER &&
@@ -141,11 +136,14 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 					    EROFS_GET_BLOCKS_FINDTAIL);
 		erofs_put_metabuf(&map.buf);
 		if (err < 0)
-			goto out_unlock;
+			goto out_put_metabuf;
 	}
+done:
 	/* paired with smp_mb() at the beginning of the function */
 	smp_mb();
 	set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
+out_put_metabuf:
+	erofs_put_metabuf(&buf);
 out_unlock:
 	clear_and_wake_up_bit(EROFS_I_BL_Z_BIT, &vi->flags);
 	return err;
-- 
2.25.1