You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
49 lines
2.0 KiB
49 lines
2.0 KiB
From: Roland McGrath <roland@redhat.com>
|
|
Date: Tue, 14 Sep 2010 19:22:58 +0000 (-0700)
|
|
Subject: x86-64, compat: Retruncate rax after ia32 syscall entry tracing
|
|
Git-commit: eefdca043e8391dcd719711716492063030b55ac
|
|
References: CVE-2010-3301 bnc#639708
|
|
Patch-mainline: 2.6.36
|
|
Introduced-by: 2.6.27
|
|
|
|
x86-64, compat: Retruncate rax after ia32 syscall entry tracing
|
|
|
|
In commit d4d6715, we reopened an old hole for a 64-bit ptracer touching a
|
|
32-bit tracee in system call entry. A %rax value set via ptrace at the
|
|
entry tracing stop gets used whole as a 32-bit syscall number, while we
|
|
only check the low 32 bits for validity.
|
|
|
|
Fix it by truncating %rax back to 32 bits after syscall_trace_enter,
|
|
in addition to testing the full 64 bits as has already been added.
|
|
|
|
Reported-by: Ben Hawkes <hawkes@sota.gen.nz>
|
|
Signed-off-by: Roland McGrath <roland@redhat.com>
|
|
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
|
|
Acked-by: Jeff Mahoney <jeffm@suse.com>
|
|
Automatically created from "patches.fixes/x86-64-compat-retruncate-rax-after-ia32-syscall-entry-tracing" by xen-port-patches.py
|
|
|
|
--- 11.3-2010-09-14.orig/arch/x86/ia32/ia32entry-xen.S 2010-05-12 09:08:52.000000000 +0200
|
|
+++ 11.3-2010-09-14/arch/x86/ia32/ia32entry-xen.S 2010-09-17 11:18:22.000000000 +0200
|
|
@@ -47,7 +47,12 @@ ia32_common:
|
|
/*
|
|
* Reload arg registers from stack in case ptrace changed them.
|
|
* We don't reload %eax because syscall_trace_enter() returned
|
|
- * the value it wants us to use in the table lookup.
|
|
+ * the %rax value we should see. Instead, we just truncate that
|
|
+ * value to 32 bits again as we did on entry from user mode.
|
|
+ * If it's a new value set by user_regset during entry tracing,
|
|
+ * this matches the normal truncation of the user-mode value.
|
|
+ * If it's -1 to make us punt the syscall, then (u32)-1 is still
|
|
+ * an appropriately invalid value.
|
|
*/
|
|
.macro LOAD_ARGS32 offset, _r9=0
|
|
.if \_r9
|
|
@@ -57,6 +62,7 @@ ia32_common:
|
|
movl \offset+48(%rsp),%edx
|
|
movl \offset+56(%rsp),%esi
|
|
movl \offset+64(%rsp),%edi
|
|
+ movl %eax,%eax /* zero extension */
|
|
.endm
|
|
|
|
.macro CFI_STARTPROC32 simple
|