From: Dmitry V. Levin <ldv@altlinux.org>
Date: Thu, 15 Aug 2019 20:23:19 +0000 (+0000)
Subject: sparc, sparc64: fix redundant get_regs invocation
X-Git-Tag: v5.3~45
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=37c8cfff11b8691c8ca8c72d122842fc0ae368e3;p=strace

sparc, sparc64: fix redundant get_regs invocation

An explicit get_regs invocation was added to arch_set_error and
arch_set_success on sparc/sparc64 by commit v5.2~27 in attempt to fix
syscall tampering on these architectures when PTRACE_GET_SYSCALL_INFO
is in use.

That change, however, did not fix the bug because set_error and
set_success already invoke get_regs on all architectures where
ptrace_setregset_or_setregs is defined, this includes sparc and sparc64.

* linux/sparc/set_error.c (sparc_set_o0_psr): Do not invoke get_regs.
* linux/sparc64/set_error.c (sparc64_set_o0_tstate): Likewise.
* NEWS (5.2): Remove the statement about syscall tampering fix
on sparc and sparc64 when PTRACE_GET_SYSCALL_INFO is in use.
---

diff --git a/NEWS b/NEWS
index 4c8b8340..17125b8d 100644
--- a/NEWS
+++ b/NEWS
@@ -33,7 +33,7 @@ Noteworthy changes in release 5.2 (2019-07-12)
   * Updated lists of ioctl commands from Linux 5.2.
 
 * Bug fixes
-  * Fixed syscall tampering on powerpc, powerpc64, sparc, and sparc64 when
+  * Fixed syscall tampering on powerpc and powerpc64 when
     PTRACE_GET_SYSCALL_INFO is in use.
   * Fixed build with cutting-edge toolchain.
 
diff --git a/linux/sparc/set_error.c b/linux/sparc/set_error.c
index cc608126..767be69d 100644
--- a/linux/sparc/set_error.c
+++ b/linux/sparc/set_error.c
@@ -9,8 +9,6 @@ static int
 sparc_set_o0_psr(struct tcb *tcp, const unsigned long o0,
 		 const unsigned long psr_set, const unsigned long psr_clear)
 {
-	if (ptrace_syscall_info_is_valid() && get_regs(tcp) < 0)
-		return -1;
 	sparc_regs.u_regs[U_REG_O0] = o0;
 	sparc_regs.psr |= psr_set;
 	sparc_regs.psr &= ~psr_clear;
diff --git a/linux/sparc64/set_error.c b/linux/sparc64/set_error.c
index 10eb380f..69778e57 100644
--- a/linux/sparc64/set_error.c
+++ b/linux/sparc64/set_error.c
@@ -10,8 +10,6 @@ sparc64_set_o0_tstate(struct tcb *tcp, const unsigned long o0,
 		      const unsigned long tstate_set,
 		      const unsigned long tstate_clear)
 {
-	if (ptrace_syscall_info_is_valid() && get_regs(tcp) < 0)
-		return -1;
 	sparc_regs.u_regs[U_REG_O0] = o0;
 	sparc_regs.tstate |= tstate_set;
 	sparc_regs.tstate &= ~tstate_clear;