libblkid: (ext) reduce false positive

Signed-off-by: 胡玮文 <huweiwen.hww@alibaba-inc.com>
(cherry picked from commit 0c5d55e52d27be933e9e61b82bd386943bd9e05c)

diff --git a/libblkid/src/superblocks/ext.c b/libblkid/src/superblocks/ext.c
index c0779c2333b306dbdac20bf6406b9aa357929613..ab4d7a8274c24be023b8db39ed0a967d6ecaed0a 100644 (file)
--- a/libblkid/src/superblocks/ext.c
+++ b/libblkid/src/superblocks/ext.c
@@ -180,6 +180,15 @@ static struct ext2_super_block *ext_get_super(
                        return NULL;
 #endif
                }
+       } else {
+               /*
+                * For legacy fs without checksum, additionally verify the
+                * block size to reduce false positive. Currently max allowed
+                * block size is 64KiB (s_log_block_size <= 6), check for 256
+                * to be more future proof.
+                */
+               if (le32_to_cpu(es->s_log_block_size) >= 256)
+                       return NULL;
        }
        if (fc)
                *fc = le32_to_cpu(es->s_feature_compat);