feat: Sysvar address check example added (#15)

Cargo.toml

@@ -10,4 +10,5 @@ members = [
     "programs/7-bump-seed-canonicalization/*",
     "programs/8-pda-sharing/*",
     "programs/9-closing-accounts/*",
+    "programs/10-sysvar-address-checking/*"
 ]

programs/10-sysvar-address-checking/insecure/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "insecure"
+version = "0.1.0"
+description = "Created with Anchor"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib", "lib"]
+name = "insecure"
+
+[features]
+no-entrypoint = []
+no-idl = []
+no-log-ix-name = []
+cpi = ["no-entrypoint"]
+default = []
+
+[profile.release]
+overflow-checks = true
+
+[dependencies]
+anchor-lang = "0.25.0"

programs/10-sysvar-address-checking/insecure/Xargo.toml

@@ -0,0 +1,2 @@
+[target.bpfel-unknown-unknown.dependencies.std]
+features = []

programs/10-sysvar-address-checking/insecure/src/lib.rs

@@ -0,0 +1,18 @@
+use anchor_lang::prelude::*;
+
+declare_id!("Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS");
+
+#[program]
+pub mod insecure {
+    use super::*;
+
+    pub fn check_sysvar_address(ctx: Context<CheckSysvarAddress>) -> Result<()> {
+        msg!("Rent Key -> {}", ctx.accounts.rent.key().to_string());
+        Ok(())
+    }
+}
+
+#[derive(Accounts)]
+pub struct CheckSysvarAddress<'info> {
+    rent: AccountInfo<'info>,
+}

programs/10-sysvar-address-checking/recommended/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "recommended"
+version = "0.1.0"
+description = "Created with Anchor"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib", "lib"]
+name = "secure"
+
+[features]
+no-entrypoint = []
+no-idl = []
+no-log-ix-name = []
+cpi = ["no-entrypoint"]
+default = []
+
+[profile.release]
+overflow-checks = true
+
+[dependencies]
+anchor-lang = "0.25.0"

programs/10-sysvar-address-checking/recommended/Xargo.toml

@@ -0,0 +1,2 @@
+[target.bpfel-unknown-unknown.dependencies.std]
+features = []

programs/10-sysvar-address-checking/recommended/src/lib.rs

@@ -0,0 +1,18 @@
+use anchor_lang::prelude::*;
+
+declare_id!("Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS");
+
+#[program]
+pub mod recommended {
+    use super::*;
+
+    pub fn check_sysvar_address(ctx: Context<CheckSysvarAddress>) -> Result<()> {
+        msg!("Rent Key -> {}", ctx.accounts.rent.key().to_string());
+        Ok(())
+    }
+}
+
+#[derive(Accounts)]
+pub struct CheckSysvarAddress<'info> {
+    rent: Sysvar<'info, Rent>,
+}

programs/10-sysvar-address-checking/secure/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "secure"
+version = "0.1.0"
+description = "Created with Anchor"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib", "lib"]
+name = "secure"
+
+[features]
+no-entrypoint = []
+no-idl = []
+no-log-ix-name = []
+cpi = ["no-entrypoint"]
+default = []
+
+[dependencies]
+anchor-lang = "0.25.0"

programs/10-sysvar-address-checking/secure/Xargo.toml

@@ -0,0 +1,2 @@
+[target.bpfel-unknown-unknown.dependencies.std]
+features = []

programs/10-sysvar-address-checking/secure/src/lib.rs

@@ -0,0 +1,19 @@
+use anchor_lang::prelude::*;
+use anchor_lang::solana_program::sysvar;
+declare_id!("Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS");
+
+#[program]
+pub mod secure {
+    use super::*;
+
+    pub fn check_sysvar_address(ctx: Context<CheckSysvarAddress>) -> Result<()> {
+        require_eq!(ctx.accounts.rent.key(), sysvar::rent::ID);
+        msg!("Rent Key -> {}", ctx.accounts.rent.key().to_string());
+        Ok(())
+    }
+}
+
+#[derive(Accounts)]
+pub struct CheckSysvarAddress<'info> {
+    rent: AccountInfo<'info>,
+}