Merge pull request #56 from archlinux/siglist

Fix UB when using empty SigList

Author: Morganamilo

alpm/src/signing.rs

@@ -7,6 +7,7 @@ use alpm_sys::*;
 
 use std::ffi::{c_void, CString};
 use std::mem::transmute;
+use std::ptr::NonNull;
 use std::{fmt, ptr, slice};
 
 #[derive(Debug, Eq, PartialEq, Copy, Clone, Ord, PartialOrd, Hash)]
@@ -67,7 +68,7 @@ impl fmt::Debug for PgpKey {
         f.debug_struct("PgpKey")
             .field("name", &self.name())
             .field("email", &self.email())
-            .field("uid", &self.uid())
+            .field("uid", &self.uid_optional())
             .field("fingerprint", &self.fingerprint())
             .field("created", &self.created())
             .field("expires", &self.expires())
@@ -82,8 +83,13 @@ impl PgpKey {
         unsafe { from_cstr(self.inner.fingerprint) }
     }
 
+    pub fn uid_optional(&self) -> Option<&str> {
+        unsafe { from_cstr_optional(self.inner.uid) }
+    }
+
+    #[deprecated = "uid may be none. Use uid_optional() instead. This function will return an option instead in the next major release."]
     pub fn uid(&self) -> &str {
-        unsafe { from_cstr(self.inner.uid) }
+        unsafe { from_cstr_optional(self.inner.uid).unwrap_or("") }
     }
 
     pub fn name(&self) -> Option<&str> {
@@ -181,7 +187,7 @@ impl SigList {
 
     pub fn results(&self) -> &[SigResult] {
         if self.inner.results.is_null() {
-            unsafe { slice::from_raw_parts(1 as *const SigResult, 0) }
+            unsafe { slice::from_raw_parts(NonNull::dangling().as_ptr(), 0) }
         } else {
             unsafe {
                 slice::from_raw_parts(self.inner.results as *const SigResult, self.inner.count)