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From 25162c795b1a2becf936bb3581d86a307ea491eb Mon Sep 17 00:00:00 2001
From: Nick Clifton <nickc@redhat.com>
Date: Thu, 15 Jul 2021 16:51:56 +0100
Subject: [PATCH] Fix a stack exhaustion problem in the Rust demangling code in
the libiberty library.
PR 99935
* rust-demangle.c: Add recursion limit.
CVE: CVE-2021-3530
Upstream-Status: Backport[https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=25162c795b1a2becf936bb3581d86a307ea491eb]
Signed-off-by: Pgowda <pgowda.cve@gmail.com>
---
libiberty/ChangeLog | 5 +++++
libiberty/rust-demangle.c | 31 +++++++++++++++++++++++++------
2 files changed, 30 insertions(+), 6 deletions(-)
diff --git a/libiberty/ChangeLog b/libiberty/ChangeLog
index bc1b35b97c4..8e39fd28eba 100644
--- a/libiberty/ChangeLog
+++ b/libiberty/ChangeLog
@@ -1,3 +1,8 @@
+2021-07-15 Nick Clifton <nickc@redhat.com>
+
+ PR 99935
+ * rust-demangle.c: Add recursion limit.
+
2021-01-04 Martin Liska <mliska@suse.cz>
* strverscmp.c: Convert to utf8 from iso8859.
diff --git a/libiberty/rust-demangle.c b/libiberty/rust-demangle.c
index 449941b56dc..df09b7b8fdd 100644
--- 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. */
+ uint recursion;
+ /* Maximum number of times demangle_path may be called recursively. */
+#define RUST_MAX_RECURSION_COUNT 1024
+#define RUST_NO_RECURSION_LIMIT ((uint) -1)
+
uint64_t bound_lifetime_depth;
};
@@ -671,6 +677,15 @@ demangle_path (struct rust_demangler *rd
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 *rd
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 *rd
}
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
@@ -1317,6 +1335,7 @@ rust_demangle_callback (const char *mang
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). */
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