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From 033bc52bb6190393c8eed80925fa78cc35b40c6d Mon Sep 17 00:00:00 2001
From: Tom Tromey <tromey@adacore.com>
Date: Wed, 16 Aug 2023 11:29:19 -0600
Subject: [PATCH] Avoid buffer overflow in ada_decode
A bug report pointed out a buffer overflow in ada_decode, which Keith
helpfully analyzed. ada_decode had a logic error when the input was
all digits. While this isn't valid -- and would probably only appear
in fuzzer tests -- it still should be handled properly.
This patch adds a missing bounds check. Tested with the self-tests in
an asan build.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30639
Reviewed-by: Keith Seitz <keiths@redhat.com>
Upstream-Status: Backport from [https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=033bc52bb6190393c8eed80925fa78cc35b40c6d]
CVE: CVE-2023-39128
Signed-off-by: Siddharth Doshi <sdoshi@mvista.com>
---
gdb/ada-lang.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 0c2d4fc..40852b6 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -56,6 +56,7 @@
#include "cli/cli-utils.h"
#include "gdbsupport/function-view.h"
#include "gdbsupport/byte-vector.h"
+#include "gdbsupport/selftest.h"
#include <algorithm>
/* Define whether or not the C operator '/' truncates towards zero for
@@ -1184,7 +1185,7 @@ ada_decode (const char *encoded)
i -= 1;
if (i > 1 && encoded[i] == '_' && encoded[i - 1] == '_')
len0 = i - 1;
- else if (encoded[i] == '$')
+ else if (i >= 0 && encoded[i] == '$')
len0 = i;
}
@@ -1350,6 +1351,18 @@ Suppress:
}
+#ifdef GDB_SELF_TEST
+
+static void
+ada_decode_tests ()
+{
+ /* This isn't valid, but used to cause a crash. PR gdb/30639. The
+ result does not really matter very much. */
+ SELF_CHECK (ada_decode ("44") == "44");
+}
+
+#endif
+
/* Table for keeping permanent unique copies of decoded names. Once
allocated, names in this table are never released. While this is a
storage leak, it should not be significant unless there are massive
@@ -14345,4 +14358,8 @@ DWARF attribute."),
gdb::observers::new_objfile.attach (ada_new_objfile_observer);
gdb::observers::free_objfile.attach (ada_free_objfile_observer);
gdb::observers::inferior_exit.attach (ada_inferior_exit);
+
+#ifdef GDB_SELF_TEST
+ selftests::register_test ("ada-decode", ada_decode_tests);
+#endif
}
--
2.24.4
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