pstore: fix potential logic issue in pstore read interface

1) in the calling of erst_read, the parameter of buffer size
maybe overflows and cause crash

2) the return value of erst_read should be checked more strictly

Signed-off-by: Chen Gong <gong.chen@linux.intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c
index ddb68c4f8d3e..e6cef8e1b534 100644
--- a/drivers/acpi/apei/erst.c
+++ b/drivers/acpi/apei/erst.c
@@ -1006,7 +1006,14 @@ skip:
         }
 
         len = erst_read(record_id, &rcd->hdr, sizeof(*rcd) +
-                          erst_erange.size);
+                        erst_info.bufsize);
+        /* The record may be cleared by others, try read next record */
+        if (len == -ENOENT)
+                goto skip;
+        else if (len < 0) {
+                rc = -1;
+                goto out;
+        }
         if (uuid_le_cmp(rcd->hdr.creator_id, CPER_CREATOR_PSTORE) != 0)
                 goto skip;