From 033bc52bb6190393c8eed80925fa78cc35b40c6d Mon Sep 17 00:00:00 2001 From: Tom Tromey 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 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 --- 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 /* 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