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Commit aaf27b60 authored by Oriol Prieto Gascó's avatar Oriol Prieto Gascó
Browse files

Check remaining bytes before attempting to read from buffer 

Test: cargo test
Bug:374338212

Change-Id: I8bd94b6613cf847a4261db65179a875d67177e0a
parent 490590b7

tools/aconfig/aconfig_storage_file/src/lib.rs

+81 −18
Original line number Diff line number Diff line
@@ -228,10 +228,14 @@ pub(crate) fn get_bucket_index(val: &[u8], num_buckets: u32) -> u32 { 


/// Read and parse bytes as u8

pub fn read_u8_from_bytes(buf: &[u8], head: &mut usize) -> Result<u8, AconfigStorageError> {

    let val =

        u8::from_le_bytes(buf[*head..*head + 1].try_into().map_err(|errmsg| {

            BytesParseFail(anyhow!("fail to parse u8 from bytes: {}", errmsg))

        })?);

    let val = u8::from_le_bytes(

        buf.get(*head..*head + 1)

            .ok_or(AconfigStorageError::BytesParseFail(anyhow!(

                "fail to parse u8 from bytes: access out of bounds"

            )))?

            .try_into()

            .map_err(|errmsg| BytesParseFail(anyhow!("fail to parse u8 from bytes: {}", errmsg)))?,

    );

    *head += 1;

    Ok(val)

}
@@ -241,10 +245,16 @@ pub(crate) fn read_u16_from_bytes( 
    buf: &[u8],

    head: &mut usize,

) -> Result<u16, AconfigStorageError> {

    let val =

        u16::from_le_bytes(buf[*head..*head + 2].try_into().map_err(|errmsg| {

    let val = u16::from_le_bytes(

        buf.get(*head..*head + 2)

            .ok_or(AconfigStorageError::BytesParseFail(anyhow!(

                "fail to parse u16 from bytes: access out of bounds"

            )))?

            .try_into()

            .map_err(|errmsg| {

                BytesParseFail(anyhow!("fail to parse u16 from bytes: {}", errmsg))

        })?);

            })?,

    );

    *head += 2;

    Ok(val)

}
@@ -256,20 +266,32 @@ pub fn read_u32_from_start_of_bytes(buf: &[u8]) -> Result<u32, AconfigStorageErr 


/// Read and parse bytes as u32

pub fn read_u32_from_bytes(buf: &[u8], head: &mut usize) -> Result<u32, AconfigStorageError> {

    let val =

        u32::from_le_bytes(buf[*head..*head + 4].try_into().map_err(|errmsg| {

    let val = u32::from_le_bytes(

        buf.get(*head..*head + 4)

            .ok_or(AconfigStorageError::BytesParseFail(anyhow!(

                "fail to parse u32 from bytes: access out of bounds"

            )))?

            .try_into()

            .map_err(|errmsg| {

                BytesParseFail(anyhow!("fail to parse u32 from bytes: {}", errmsg))

        })?);

            })?,

    );

    *head += 4;

    Ok(val)

}



// Read and parse bytes as u64

pub fn read_u64_from_bytes(buf: &[u8], head: &mut usize) -> Result<u64, AconfigStorageError> {

    let val =

        u64::from_le_bytes(buf[*head..*head + 8].try_into().map_err(|errmsg| {

    let val = u64::from_le_bytes(

        buf.get(*head..*head + 8)

            .ok_or(AconfigStorageError::BytesParseFail(anyhow!(

                "fail to parse u64 from bytes: access out of bounds"

            )))?

            .try_into()

            .map_err(|errmsg| {

                BytesParseFail(anyhow!("fail to parse u64 from bytes: {}", errmsg))

        })?);

            })?,

    );

    *head += 8;

    Ok(val)

}
@@ -280,7 +302,20 @@ pub(crate) fn read_str_from_bytes( 
    head: &mut usize,

) -> Result<String, AconfigStorageError> {

    let num_bytes = read_u32_from_bytes(buf, head)? as usize;

    let val = String::from_utf8(buf[*head..*head + num_bytes].to_vec())

    // TODO(opg): Document this limitation and check it when creating files.

    if num_bytes > 1024 {

        return Err(AconfigStorageError::BytesParseFail(anyhow!(

            "fail to parse string from bytes, string is too long (found {}, max is 1024)",

            num_bytes

        )));

    }

    let val = String::from_utf8(

        buf.get(*head..*head + num_bytes)

            .ok_or(AconfigStorageError::BytesParseFail(anyhow!(

                "fail to parse string from bytes: access out of bounds"

            )))?

            .to_vec(),

    )

    .map_err(|errmsg| BytesParseFail(anyhow!("fail to parse string from bytes: {}", errmsg)))?;

    *head += num_bytes;

    Ok(val)
@@ -532,6 +567,34 @@ mod tests { 
        create_test_package_table, write_bytes_to_temp_file,

    };



    #[test]

    fn test_list_flags_with_missing_files_error() {

        let flag_list_error = list_flags("does", "not", "exist").unwrap_err();

        assert_eq!(

            format!("{:?}", flag_list_error),

            format!(

                "FileReadFail(Failed to open file does: No such file or directory (os error 2))"

            )

        );

    }



    #[test]

    fn test_list_flags_with_invalid_files_error() {

        let invalid_bytes: [u8; 3] = [0; 3];

        let package_table = write_bytes_to_temp_file(&invalid_bytes).unwrap();

        let flag_table = write_bytes_to_temp_file(&invalid_bytes).unwrap();

        let flag_value_list = write_bytes_to_temp_file(&invalid_bytes).unwrap();

        let package_table_path = package_table.path().display().to_string();

        let flag_table_path = flag_table.path().display().to_string();

        let flag_value_list_path = flag_value_list.path().display().to_string();

        let flag_list_error =

            list_flags(&package_table_path, &flag_table_path, &flag_value_list_path).unwrap_err();

        assert_eq!(

            format!("{:?}", flag_list_error),

            format!("BytesParseFail(fail to parse u32 from bytes: access out of bounds)")

        );

    }



    #[test]

    // this test point locks down the flag list api

    fn test_list_flag() {