[patch] pax-utils-9999-scanelf-fix-out-of-bounds-access-in-ia64.patch

pax-utils-9999-scanelf-fix-out-of-bounds-access-in-ia64.patch (text/plain), 1.98 KB, created by Sergei Trofimovich (RETIRED) on 2017-08-19 09:49:00 UTC

From e95103c40d0541fbcdb4b84b000832d9b1b83b8d Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <[e-mail]>
Date: Sat, 19 Aug 2017 10:34:41 +0100
Subject: [PATCH] scanelf: fix out-of-bounds access in ia64

commit 2eb852129394f97dae89c0ff1f9f48637edcb0e9
slightly changed decoder and added unchecked
read from elf header:

```
       switch (EGET(dpltrel->d_un.d_val)) { \
       case DT_REL: \
               rel = REL##B(elf->vdata + EGET(drel->d_un.d_val)); \
```

On ia64 'EGET(drel->d_un.d_val)' returns absolute address:

```
    $ dumpelf bug/luatex
    ...
    /* Dynamic tag #31 'DT_RELA' 0x97E310 */
    {
        .d_tag     = 0x7        ,
        .d_un      = {
                .d_val = 0x4000000000031C30 ,
                .d_ptr = 0x4000000000031C30 ,
        },
    },
```

That causes 'scanelf' crash on binaries like 'luatex'.

This change restores check and loudly skips such sections:
    scanelf: bug/luatex: DT_RELA is out of file range

Bug: https://bugs.gentoo.org/624356
Signed-off-by: Sergei Trofimovich <[e-mail]>
---
 scanelf.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/scanelf.c b/scanelf.c
index 1ead891..a054408 100644
--- a/scanelf.c
+++ b/scanelf.c
@@ -607,11 +607,23 @@ static char *scanelf_file_textrels(elfobj *elf, char *found_textrels, char *foun
 	} \
 	switch (EGET(dpltrel->d_un.d_val)) { \
 	case DT_REL: \
+		if (!VALID_RANGE(elf, EGET(drel->d_un.d_val), sizeof (drel->d_un.d_val))) { \
+			rel = NULL; \
+			rela = NULL; \
+			warn("%s: DT_REL is out of file range", elf->filename); \
+			break; \
+		} \
 		rel = REL##B(elf->vdata + EGET(drel->d_un.d_val)); \
 		rela = NULL; \
 		pltrel = DT_REL; \
 		break; \
 	case DT_RELA: \
+		if (!VALID_RANGE(elf, EGET(drel->d_un.d_val), sizeof (drel->d_un.d_val))) { \
+			rel = NULL; \
+			rela = NULL; \
+			warn("%s: DT_RELA is out of file range", elf->filename); \
+			break; \
+		} \
 		rel = NULL; \
 		rela = RELA##B(elf->vdata + EGET(drel->d_un.d_val)); \
 		pltrel = DT_RELA; \
-- 
2.14.1