From a49f2461c3c012633027f4dbf898fbc51d5aac85 Mon Sep 17 00:00:00 2001 From: Roman Lebedev Date: Sat, 13 Jun 2015 16:57:20 +0300 Subject: [PATCH] babl_model_new(): fix global-buffer-overflow If we pass a string into this function, and this string is shorter than sizeof(Babl), macro BABL_IS_BABL() will read past string bounds, and bad things may happen. NOTE: if a string will be passed into this function, that is not handled by those if (!strcmp (arg, "<...>")), global-buffer-overflow will still happen. i am not sure if/what can be done about it :( Fixes following error: ================================================================= ==31464==ERROR: AddressSanitizer: global-buffer-overflow on address 0x7f1c25907940 at pc 0x7f1c258f7636 bp 0x7ffdc4838670 sp 0x7ffdc4838668 READ of size 4 at 0x7f1c25907940 thread T0 0 0x7f1c258f7635 in babl_model_new /home/lebedevri/src/_GIMP/babl/babl/babl-model.c:114 1 0x7f1c258e4ce5 in babl_core_init /home/lebedevri/src/_GIMP/babl/babl/babl-core.c:128 2 0x7f1c258e1379 in babl_init /home/lebedevri/src/_GIMP/babl/babl/babl.c:145 3 0x7f1c2a0923d1 in gegl_post_parse_hook (/usr/local/lib/libgegl-0.3.so.0+0x523d1) 4 0x7f1c25195238 in g_option_context_parse (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x55238) 5 0x7f1c25196193 in g_option_context_parse_strv (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x56193) 6 0x48b8cf in main (/usr/local/bin/gimp-2.9+0x48b8cf) 7 0x7f1c241a9b44 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b44) 8 0x486b68 (/usr/local/bin/gimp-2.9+0x486b68) 0x7f1c25907943 is located 0 bytes to the right of global variable '*.LC1' from 'babl-core.c' (0x7f1c25907940) of size 3 '*.LC1' is ascii string 'id' SUMMARY: AddressSanitizer: global-buffer-overflow /home/lebedevri/src/_GIMP/babl/babl/babl-model.c:114 babl_model_new Shadow bytes around the buggy address: 0x0fe404b18f10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 =>0x0fe404b18f20: 05 f9 f9 f9 f9 f9 f9 f9[03]f9 f9 f9 f9 f9 f9 f9 0x0fe404b18f30: 07 f9 f9 f9 f9 f9 f9 f9 07 f9 f9 f9 f9 f9 f9 f9 Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Heap right redzone: fb Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack partial redzone: f4 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Contiguous container OOB:fc ASan internal: fe ==31464==ABORTING --- babl/babl-model.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/babl/babl-model.c b/babl/babl-model.c index dda1cbe..02f3c0b 100644 --- a/babl/babl-model.c +++ b/babl/babl-model.c @@ -111,7 +111,19 @@ babl_model_new (void *first_argument, while (1) { - if (BABL_IS_BABL (arg)) + /* first, we assume arguments to be strings */ + if (!strcmp (arg, "id")) + { + id = va_arg (varg, int); + } + + else if (!strcmp (arg, "name")) + { + assigned_name = va_arg (varg, char *); + } + + /* if we didn't point to a known string, we assume argument to be babl */ + else if (BABL_IS_BABL (arg)) { Babl *bablc = (Babl *) arg; @@ -156,16 +168,6 @@ babl_model_new (void *first_argument, break; } } - /* if we didn't point to a babl, we assume arguments to be strings */ - else if (!strcmp (arg, "id")) - { - id = va_arg (varg, int); - } - - else if (!strcmp (arg, "name")) - { - assigned_name = va_arg (varg, char *); - } else { -- 2.30.2