From 5a2f83cd86ce824167fa7ea8e5357c014034ed46 Mon Sep 17 00:00:00 2001

From: Jakub Filak <jfilak@redhat.com>

Date: Mon, 9 Jun 2014 17:13:09 +0200

Subject: [ABRT PATCH 45/66] gdb: disable loading of auto-loaded files

https://sourceware.org/gdb/onlinedocs/gdb/Auto_002dloading.html

There are two main reasons for doing so:

1. we cannot trust anybody

  - the auto-loaded file may change the output format

  - security?

2. bugs in such a files (#817)

Resolves: #1128637

Signed-off-by: Jakub Filak <jfilak@redhat.com>

---

 src/lib/hooklib.c | 40 +++++++++++++++++++++-------------------

 1 file changed, 21 insertions(+), 19 deletions(-)

diff --git a/src/lib/hooklib.c b/src/lib/hooklib.c

index 4a50727..21ad9e0 100644

--- a/src/lib/hooklib.c

+++ b/src/lib/hooklib.c

@@ -252,10 +252,12 @@ char *get_backtrace(const char *dump_dir_name, unsigned timeout_sec, const char

     /* Let user know what's going on */

     log(_("Generating backtrace"));

-    char *args[21];

+    char *args[23];

     args[0] = (char*)"gdb";

     args[1] = (char*)"-batch";

     args[2] = (char*)"-ex";

+    args[3] = (char*)"set auto-load off";

+    args[4] = (char*)"-ex";

     struct strbuf *set_debug_file_directory = strbuf_new();

     if(debuginfo_dirs == NULL)

     {

@@ -278,7 +280,7 @@ char *get_backtrace(const char *dump_dir_name, unsigned timeout_sec, const char

             p = colon_or_nul;

         }

     }

-    args[3] = strbuf_free_nobuf(set_debug_file_directory);

+    args[5] = strbuf_free_nobuf(set_debug_file_directory);

     /* "file BINARY_FILE" is needed, without it gdb cannot properly

      * unwind the stack. Currently the unwind information is located

@@ -300,27 +302,27 @@ char *get_backtrace(const char *dump_dir_name, unsigned timeout_sec, const char

      * TODO: check mtimes on COREFILE and BINARY_FILE and not supply

      * BINARY_FILE if it is newer (to at least avoid gdb complaining).

      */

-    args[4] = (char*)"-ex";

-    args[5] = xasprintf("file %s", executable);

-    free(executable);

-

     args[6] = (char*)"-ex";

-    args[7] = xasprintf("core-file %s/"FILENAME_COREDUMP, dump_dir_name);

+    args[7] = xasprintf("file %s", executable);

+    free(executable);

     args[8] = (char*)"-ex";

-    /*args[9] = ... see below */

+    args[9] = xasprintf("core-file %s/"FILENAME_COREDUMP, dump_dir_name);

+

     args[10] = (char*)"-ex";

-    args[11] = (char*)"info sharedlib";

-    /* glibc's abort() stores its message in __abort_msg variable */

+    /*args[11] = ... see below */

     args[12] = (char*)"-ex";

-    args[13] = (char*)"print (char*)__abort_msg";

+    args[13] = (char*)"info sharedlib";

+    /* glibc's abort() stores its message in __abort_msg variable */

     args[14] = (char*)"-ex";

-    args[15] = (char*)"print (char*)__glib_assert_msg";

+    args[15] = (char*)"print (char*)__abort_msg";

     args[16] = (char*)"-ex";

-    args[17] = (char*)"info all-registers";

+    args[17] = (char*)"print (char*)__glib_assert_msg";

     args[18] = (char*)"-ex";

-    args[19] = (char*)"disassemble";

-    args[20] = NULL;

+    args[19] = (char*)"info all-registers";

+    args[20] = (char*)"-ex";

+    args[21] = (char*)"disassemble";

+    args[22] = NULL;

     /* Get the backtrace, but try to cap its size */

     /* Limit bt depth. With no limit, gdb sometimes OOMs the machine */

@@ -330,9 +332,9 @@ char *get_backtrace(const char *dump_dir_name, unsigned timeout_sec, const char

     char *bt = NULL;

     while (1)

     {

-        args[9] = xasprintf("%s backtrace %u%s", thread_apply_all, bt_depth, full);

+        args[11] = xasprintf("%s backtrace %u%s", thread_apply_all, bt_depth, full);

         bt = exec_vp(args, /*redirect_stderr:*/ 1, timeout_sec, NULL);

-        free(args[9]);

+        free(args[11]);

         if ((bt && strnlen(bt, 256*1024) < 256*1024) || bt_depth <= 32)

         {

             break;

@@ -357,7 +359,7 @@ char *get_backtrace(const char *dump_dir_name, unsigned timeout_sec, const char

          * End of assembler dump.

          * (IOW: "empty" dump)

          */

-        args[19] = (char*)"disassemble $pc-20, $pc+64";

+        args[21] = (char*)"disassemble $pc-20, $pc+64";

         if (bt_depth <= 64 && thread_apply_all[0] != '\0')

         {

@@ -373,9 +375,9 @@ char *get_backtrace(const char *dump_dir_name, unsigned timeout_sec, const char

         }

     }

-    free(args[3]);

     free(args[5]);

     free(args[7]);

+    free(args[9]);

     return bt;

 }

-- 

1.8.3.1