From 9d8713f622e545f7c6eb55270b5053242d2e62b6 Mon Sep 17 00:00:00 2001
From: Julian Mutter <julian.mutter@comumail.de>
Date: Sun, 8 Dec 2024 15:21:49 +0100
Subject: [PATCH] Prevent poppler page request for too large page numbers

---
 src/cache.rs | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/cache.rs b/src/cache.rs
index 2bdadd1..82a8323 100644
--- a/src/cache.rs
+++ b/src/cache.rs
@@ -51,25 +51,27 @@ impl PageCache {
         }
     }
 
-    pub fn cache_page(&mut self, page_number: PageNumber, height: i32) -> Option<CacheResponse> {
+    pub fn cache_page(&mut self, page_number: PageNumber, height: i32) -> Result<Option<CacheResponse>> {
         debug!("Caching page {}", page_number);
         if page_number.abs_diff(self.last_requested_page_number)
             > self.max_num_stored_pages.div_ceil(2)
         {
-            debug!("Page too far from reader, aborting caching call");
-            return None;
+            bail!("Page too far from reader, aborting caching call");
         }
-
-        let begin_of_cashing = Instant::now();
         if let Some(page) = self.pages.get(&page_number) {
             if page.height() >= height {
                 debug!("Page already in cache");
-                return None;
+                return Ok(None);
             }
         }
+        if page_number >= self.document.n_pages() as usize {
+            bail!("Requested page {} has too high number and is not in the document", page_number);
+        }
 
+        let begin_of_cashing = Instant::now();
         let mut response = None;
 
+        println!("Getting page form poppler: {}", page_number);
         if let Some(page) = self.document.page(page_number as i32) {
             let pages = vec![Rc::new(page)];
             let texture = draw::draw_pages_to_texture(&pages, height, &self.color_mode);
@@ -91,7 +93,7 @@ impl PageCache {
             page_number,
             begin_of_cashing.elapsed().as_millis()
         );
-        response
+        Ok(response)
     }
 
     fn remove_most_distant_page(&mut self) -> anyhow::Result<()> {
@@ -130,7 +132,7 @@ impl PageCache {
     fn process_command(&mut self, command: CacheCommand) -> Result<Option<CacheResponse>> {
         debug!("Processing command: {:?}...", command);
         match command {
-            CacheCommand::Cache(command) => Ok(self.cache_page(command.page, command.height)),
+            CacheCommand::Cache(command) => Ok(self.cache_page(command.page, command.height)?),
             CacheCommand::Retrieve(command) => match command {
                 RetrievePagesCommand::GetCurrentTwoPages { page_left_number } => {
                     let page_left = self.get_page_or_cache(page_left_number)?;