Import patch from mainline GCC to fix an infinite recusion in the Rust demangler.

	PR 98886
	PR 99935
	* rust-demangle.c (struct rust_demangler): Add a recursion
	counter.
	(demangle_path): Increment/decrement the recursion counter upon
	entry and exit.  Fail if the counter exceeds a fixed limit.
	(demangle_type): Likewise.
	(rust_demangle_callback): Initialise the recursion counter,
	disabling if requested by the option flags.

diff --git a/libiberty/ChangeLog b/libiberty/ChangeLog
index 40611e56ff4713dd3883ea56069c3611f31d6b1e..de3a6eeef527eadd2ef3430b63d5bd706f989d90 100644 (file)
--- a/libiberty/ChangeLog
+++ b/libiberty/ChangeLog
@@ -1,3 +1,15 @@
+2022-01-31  Nick Clifton  <nickc@redhat.com>
+
+       PR 98886
+       PR 99935
+       * rust-demangle.c (struct rust_demangler): Add a recursion
+       counter.
+       (demangle_path): Increment/decrement the recursion counter upon
+       entry and exit.  Fail if the counter exceeds a fixed limit.
+       (demangle_type): Likewise.
+       (rust_demangle_callback): Initialise the recursion counter,
+       disabling if requested by the option flags.
+
 2022-01-15  Martin Sebor  <msebor@redhat.com>
 
        * regex.c: Suppress -Wuse-after-free.

diff --git a/libiberty/rust-demangle.c b/libiberty/rust-demangle.c
index 18c760491bdc827c65dad4c3ec2cbf56a91ada2e..3b24d63892a9732f335860140e481c7bd696fe2f 100644 (file)
--- a/libiberty/rust-demangle.c
+++ b/libiberty/rust-demangle.c
@@ -74,6 +74,12 @@ struct rust_demangler
   /* Rust mangling version, with legacy mangling being -1. */
   int version;
 
+  /* Recursion depth.  */
+  unsigned int recursion;
+  /* Maximum number of times demangle_path may be called recursively.  */
+#define RUST_MAX_RECURSION_COUNT  1024
+#define RUST_NO_RECURSION_LIMIT   ((unsigned int) -1)
+
   uint64_t bound_lifetime_depth;
 };
 
@@ -671,6 +677,15 @@ demangle_path (struct rust_demangler *rdm, int in_value)
   if (rdm->errored)
     return;
 
+  if (rdm->recursion != RUST_NO_RECURSION_LIMIT)
+    {
+      ++ rdm->recursion;
+      if (rdm->recursion > RUST_MAX_RECURSION_COUNT)
+       /* FIXME: There ought to be a way to report
+          that the recursion limit has been reached.  */
+       goto fail_return;
+    }
+
   switch (tag = next (rdm))
     {
     case 'C':
@@ -688,10 +703,7 @@ demangle_path (struct rust_demangler *rdm, int in_value)
     case 'N':
       ns = next (rdm);
       if (!ISLOWER (ns) && !ISUPPER (ns))
-        {
-          rdm->errored = 1;
-          return;
-        }
+       goto fail_return;
 
       demangle_path (rdm, in_value);
 
@@ -776,9 +788,15 @@ demangle_path (struct rust_demangler *rdm, int in_value)
         }
       break;
     default:
-      rdm->errored = 1;
-      return;
+      goto fail_return;
     }
+  goto pass_return;
+
+ fail_return:
+  rdm->errored = 1;
+ pass_return:
+  if (rdm->recursion != RUST_NO_RECURSION_LIMIT)
+    -- rdm->recursion;
 }
 
 static void
@@ -870,6 +888,19 @@ demangle_type (struct rust_demangler *rdm)
       return;
     }
 
+   if (rdm->recursion != RUST_NO_RECURSION_LIMIT)
+    {
+      ++ rdm->recursion;
+      if (rdm->recursion > RUST_MAX_RECURSION_COUNT)
+       /* FIXME: There ought to be a way to report
+          that the recursion limit has been reached.  */
+       {
+         rdm->errored = 1;
+         -- rdm->recursion;
+         return;
+       }
+    }
+
   switch (tag)
     {
     case 'R':
@@ -1030,6 +1061,9 @@ demangle_type (struct rust_demangler *rdm)
       rdm->next--;
       demangle_path (rdm, 0);
     }
+
+  if (rdm->recursion != RUST_NO_RECURSION_LIMIT)
+    -- rdm->recursion;
 }
 
 /* A trait in a trait object may have some "existential projections"
@@ -1320,6 +1354,7 @@ rust_demangle_callback (const char *mangled, int options,
   rdm.skipping_printing = 0;
   rdm.verbose = (options & DMGL_VERBOSE) != 0;
   rdm.version = 0;
+  rdm.recursion = (options & DMGL_NO_RECURSE_LIMIT) ? RUST_NO_RECURSION_LIMIT : 0;
   rdm.bound_lifetime_depth = 0;
 
   /* Rust symbols always start with _R (v0) or _ZN (legacy). */