Add secure padding for save-image

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 - `save-image` now checks if the ELF contains the app descriptor (#920)
+- Add support for secure padding for save-image (#876)
 
 ### Changed
 

cargo-espflash/src/main.rs

@@ -373,6 +373,7 @@ fn flash(args: FlashArgs, config: &Config) -> Result<()> {
             config,
             chip,
             target_xtal_freq,
+            args.idf_format_args.secure_pad_v2,
         );
         let image_format = make_image_format(
             &elf_data,
@@ -643,6 +644,7 @@ fn save_image(args: SaveImageArgs, config: &Config) -> Result<()> {
         config,
         args.save_image_args.chip,
         xtal_freq,
+        args.idf_format_args.secure_pad_v2,
     );
     let image_format = make_image_format(
         &elf_data,

espflash/src/bin/espflash.rs

@@ -286,6 +286,7 @@ fn flash(args: FlashArgs, config: &Config) -> Result<()> {
             config,
             chip,
             target_xtal_freq,
+            args.idf_format_args.secure_pad_v2,
         );
         let image_format = make_image_format(
             &elf_data,
@@ -370,6 +371,7 @@ fn save_image(args: SaveImageArgs, config: &Config) -> Result<()> {
         config,
         args.save_image_args.chip,
         xtal_freq,
+        args.idf_format_args.secure_pad_v2,
     );
     let image_format = make_image_format(
         &elf_data,

espflash/src/cli/mod.rs

@@ -279,6 +279,9 @@ pub struct IdfFormatArgs {
     /// Label of target app partition
     #[arg(long, value_name = "LABEL")]
     pub target_app_partition: Option<String>,
+    /// Whether to apply padding for secure boot v2
+    #[arg(long)]
+    pub secure_pad_v2: bool,
 }
 
 /// Arguments for connection and monitoring
@@ -1100,6 +1103,7 @@ pub fn make_flash_data(
     config: &Config,
     chip: Chip,
     xtal_freq: XtalFrequency,
+    secure_pad_v2: bool,
 ) -> FlashData {
     // Create flash settings with precedence
     let mode = flash_config_args
@@ -1121,6 +1125,7 @@ pub fn make_flash_data(
         image_args.mmu_page_size,
         chip,
         xtal_freq,
+        secure_pad_v2,
     )
 }
 

espflash/src/flasher/mod.rs

@@ -488,6 +488,8 @@ pub struct FlashData {
     pub chip: Chip,
     /// Crystal frequency.
     pub xtal_freq: XtalFrequency,
+    /// Whether to add secure boot V2 padding.
+    pub secure_pad_v2: bool,
 }
 
 impl FlashData {
@@ -498,13 +500,15 @@ impl FlashData {
         mmu_page_size: Option<u32>,
         chip: Chip,
         xtal_freq: XtalFrequency,
+        secure_pad_v2: bool,
     ) -> Self {
         FlashData {
             flash_settings,
             min_chip_rev,
             mmu_page_size,
             chip,
             xtal_freq,
+            secure_pad_v2,
         }
     }
 }

espflash/src/image_format/idf.rs

@@ -514,6 +514,18 @@ impl<'a> IdfBootloaderFormat<'a> {
             segment_count += 1;
         }
 
+        if flash_data.secure_pad_v2 {
+            let current_size = data.len();
+            let padding_size = (65536 - ((current_size + 56) % 65536)) % 65536;
+            let padding_bytes = vec![0; padding_size];
+            let segment = Segment {
+                addr: 0,
+                data: Cow::Owned(padding_bytes),
+            };
+            checksum = save_segment(&mut data, &segment, checksum)?;
+            segment_count += 1;
+        }
+
         let padding = 15 - (data.len() % 16);
         let padding = &[0u8; 16][0..padding];
         data.write_all(padding)?;