From 460e6ba75ae0dad8574cbeace6c6b33569ce89df Mon Sep 17 00:00:00 2001
From: "Neal H. Walfield" <neal@gnu.org>
Date: Fri, 20 Aug 2021 14:47:09 +0200
Subject: [PATCH] Have the engine pass a malloc and free to Sequoia's
 pgp_init_.

---
 src/ffi.rs         | 11 +++++++++++
 src/lib.rs         | 12 ++++++++++--
 src/pep/session.rs | 24 ++++++++++++++++++++++--
 3 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/src/ffi.rs b/src/ffi.rs
index b67e267..9a3ba28 100644
--- a/src/ffi.rs
+++ b/src/ffi.rs
@@ -1,3 +1,14 @@
+use libc::{
+    c_void,
+    size_t,
+};
+
+/// How to free the memory allocated by the callback.
+pub type Free = unsafe extern "C" fn(*mut c_void);
+
+/// How to free the memory allocated by the callback.
+pub type Malloc = unsafe extern "C" fn(size_t) -> *mut c_void;
+
 // Wraps an ffi function.
 //
 // This wrapper allows the function to return a Result.  The Ok
diff --git a/src/lib.rs b/src/lib.rs
index cb857ab..fa5868e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -22,7 +22,6 @@ use std::time::{
 use libc::{
     c_char,
     c_uint,
-    malloc,
     size_t,
     time_t,
 };
@@ -106,6 +105,8 @@ use pep::{
     Timestamp,
 };
 #[macro_use] mod ffi;
+use ffi::{Malloc, Free};
+
 mod keystore;
 use keystore::Keystore;
 mod buffer;
@@ -199,9 +200,12 @@ fn _pgp_get_decrypted_key_iter<'a, I>(iter: I, pass: Option<&Password>)
     }
 }
 
+
 // PEP_STATUS pgp_init(PEP_SESSION session, bool in_first)
 ffi!(fn pgp_init_(session: *mut Session, _in_first: bool,
                   per_user_directory: *const c_char,
+                  malloc: Malloc,
+                  free: Free,
                   session_size: c_uint,
                   session_cookie_offset: c_uint,
                   session_curr_passphrase_offset: c_uint,
@@ -273,7 +277,7 @@ ffi!(fn pgp_init_(session: *mut Session, _in_first: bool,
     };
 
     let ks = keystore::Keystore::init(Path::new(per_user_directory))?;
-    session.init(ks);
+    session.init(ks, malloc, free);
 
     Ok(())
 });
@@ -701,6 +705,7 @@ ffi!(fn pgp_decrypt_and_verify(session: *mut Session,
     -> Result<()>
 {
     let session = Session::as_mut(session);
+    let malloc = session.malloc();
 
     if ctext.is_null() {
         return Err(Error::IllegalValue(
@@ -943,6 +948,7 @@ ffi!(fn pgp_sign_only(
     -> Result<()>
 {
     let session = Session::as_mut(session);
+    let malloc = session.malloc();
 
     if fpr.is_null() {
         return Err(Error::IllegalValue(
@@ -1048,6 +1054,7 @@ fn pgp_encrypt_sign_optional(
     tracer!(*crate::TRACE, "pgp_encrypt_sign_optional");
 
     let session = Session::as_mut(session);
+    let malloc = session.malloc();
 
     if ptext.is_null() {
         return Err(Error::IllegalValue(
@@ -1679,6 +1686,7 @@ ffi!(fn pgp_export_keydata(session: *mut Session,
     -> Result<()>
 {
     let session = Session::as_mut(session);
+    let malloc = session.malloc();
 
     if fpr.is_null() {
         return Err(Error::IllegalValue("fpr must not be NULL".into()));
diff --git a/src/pep/session.rs b/src/pep/session.rs
index 971e4ac..37a8a00 100644
--- a/src/pep/session.rs
+++ b/src/pep/session.rs
@@ -11,11 +11,14 @@ use crate::Error;
 use crate::Keystore;
 use crate::PepCipherSuite;
 use crate::Result;
+use crate::{Malloc, Free};
 
 const MAGIC: u64 = 0xE3F3_05AD_48EE_0DF5;
 
 pub struct State {
     ks: Keystore,
+    malloc: Malloc,
+    free: Free,
     magic: u64,
 }
 
@@ -72,6 +75,8 @@ impl Session {
             version: ptr::null(),
             state: Box::into_raw(Box::new(State {
                 ks: Keystore::init_in_memory().unwrap(),
+                malloc: libc::malloc,
+                free: libc::free,
                 magic: MAGIC,
             })),
             curr_passphrase: ptr::null(),
@@ -82,12 +87,16 @@ impl Session {
     }
 
     pub fn init(&mut self,
-                ks: Keystore)
+                ks: Keystore,
+                malloc: Malloc,
+                free: Free)
     {
         assert!(self.state.is_null());
 
         self.state = Box::into_raw(Box::new(State {
             ks: ks,
+            malloc: malloc,
+            free: free,
             magic: MAGIC,
         }));
     }
@@ -112,6 +121,16 @@ impl Session {
         &mut State::as_mut(self.state).ks
     }
 
+    /// Returns the application's malloc routine.
+    pub fn malloc(&self) -> Malloc {
+        State::as_mut(self.state).malloc
+    }
+
+    /// Returns the application's free routine.
+    pub fn free(&self) -> Free {
+        State::as_mut(self.state).free
+    }
+
     /// Returns the value of curr_passphrase.
     pub fn curr_passphrase(&self) -> Option<Password> {
         unsafe {
@@ -190,7 +209,8 @@ mod tests {
             session.deinit();
 
             // If the state pointer is non-NULL, this will panic.
-            session.init(Keystore::init_in_memory().unwrap());
+            session.init(Keystore::init_in_memory().unwrap(),
+                         libc::malloc, libc::free);
             let ks = session.keystore() as *mut _;
             let ks2 = session.keystore() as *mut _;
             assert!(ptr::eq(ks, ks2));
-- 
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