[pbs-devel] [PATCH proxmox-backup] tape: changer: handle invalid descriptor data from library in status page

[Dominik Csapak <d.csapak@proxmox.com>]

We get the descriptor length from the library and use that in
'chunks_exact', which panics on length 0. Catch that case
and bail out, since that makes no sense here anyway.

This could prevent a panic, in case a library sends wrong data.

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
 src/tape/changer/sg_pt_changer.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/tape/changer/sg_pt_changer.rs b/src/tape/changer/sg_pt_changer.rs
index c94eaf2e..3124b96f 100644
--- a/src/tape/changer/sg_pt_changer.rs
+++ b/src/tape/changer/sg_pt_changer.rs
@@ -710,7 +710,13 @@ fn decode_element_status_page(
 
             let descr_data = reader.read_exact_allocated(len)?;
 
-            for descriptor in descr_data.chunks_exact(subhead.descriptor_length as usize) {
+            let descr_len = subhead.descriptor_length as usize;
+
+            if descr_len == 0 {
+                bail!("got elements, but descriptor length 0");
+            }
+
+            for descriptor in descr_data.chunks_exact(descr_len) {
                 let mut reader = &descriptor[..];
 
                 match subhead.element_type_code {
-- 
2.30.2