diff --git a/tools/aconfig/aconfig_storage_file/src/flag_value.rs b/tools/aconfig/aconfig_storage_file/src/flag_value.rs index 86f75ce62a..c8b52a998f 100644 --- a/tools/aconfig/aconfig_storage_file/src/flag_value.rs +++ b/tools/aconfig/aconfig_storage_file/src/flag_value.rs @@ -18,7 +18,7 @@ //! and deserialization use crate::{read_str_from_bytes, read_u32_from_bytes, read_u8_from_bytes}; -use anyhow::Result; +use anyhow::{anyhow, Result}; /// Flag value header struct #[derive(PartialEq, Debug)] @@ -86,6 +86,29 @@ impl FlagValueList { } } +/// Query flag value +pub fn get_boolean_flag_value(buf: &[u8], flag_offset: u32) -> Result { + let interpreted_header = FlagValueHeader::from_bytes(buf)?; + if interpreted_header.version > crate::FILE_VERSION { + return Err(anyhow!( + "Cannot read storage file with a higher version of {} with lib version {}", + interpreted_header.version, + crate::FILE_VERSION + )); + } + + let mut head = (interpreted_header.boolean_value_offset + flag_offset) as usize; + + // TODO: right now, there is only boolean flags, with more flag value types added + // later, the end of boolean flag value section should be updated (b/322826265). + if head >= interpreted_header.file_size as usize { + return Err(anyhow!("Flag value offset goes beyond the end of the file.")); + } + + let val = read_u8_from_bytes(buf, &mut head)?; + Ok(val == 1) +} + #[cfg(test)] mod tests { use super::*; @@ -116,4 +139,47 @@ mod tests { assert!(reinterpreted_value_list.is_ok()); assert_eq!(&flag_value_list, &reinterpreted_value_list.unwrap()); } + + #[test] + // this test point locks down flag value query + fn test_flag_value_query() { + let flag_value_list = create_test_flag_value_list().unwrap().as_bytes(); + let baseline: Vec = vec![false, true, false, false, true, true, false, true]; + for (offset, expected_value) in baseline.into_iter().enumerate() { + let flag_value = + get_boolean_flag_value(&flag_value_list[..], offset as u32) + .unwrap(); + assert_eq!(flag_value, expected_value); + } + } + + #[test] + // this test point locks down query beyond the end of boolean section + fn test_boolean_out_of_range() { + let flag_value_list = create_test_flag_value_list().unwrap().as_bytes(); + let error = get_boolean_flag_value(&flag_value_list[..], 8) + .unwrap_err(); + assert_eq!( + format!("{:?}", error), + "Flag value offset goes beyond the end of the file." + ); + } + + #[test] + // this test point locks down query error when file has a higher version + fn test_higher_version_storage_file() { + let mut value_list = create_test_flag_value_list().unwrap(); + value_list.header.version = crate::FILE_VERSION + 1; + let flag_value = value_list.as_bytes(); + let error = get_boolean_flag_value(&flag_value[..], 4) + .unwrap_err(); + assert_eq!( + format!("{:?}", error), + format!( + "Cannot read storage file with a higher version of {} with lib version {}", + crate::FILE_VERSION + 1, + crate::FILE_VERSION + ) + ); + } }