From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2] powerpc/uaccess: fix warning/error with access_ok()
Date: Thu, 18 Oct 2018 09:40:34 +0000 (UTC) [thread overview]
Message-ID: <a56d58b1d98ef47461b72ff94380c4e2dd953fd1.1539855545.git.christophe.leroy@c-s.fr> (raw)
With the following peace of code, the following compilation warning
is encountered:
if (_IOC_DIR(ioc) != _IOC_NONE) {
int verify = _IOC_DIR(ioc) & _IOC_READ ? VERIFY_WRITE : VERIFY_READ;
if (!access_ok(verify, ioarg, _IOC_SIZE(ioc))) {
drivers/platform/test/dev.c: In function ‘my_ioctl’:
drivers/platform/test/dev.c:219:7: warning: unused variable ‘verify’ [-Wunused-variable]
int verify = _IOC_DIR(ioc) & _IOC_READ ? VERIFY_WRITE : VERIFY_READ;
This patch fixes it by handing the type to __access_ok(), changing it
to an inline function for PPC64 as already done for PPC32
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
v2: fixed the three direct users of __access_ok()
arch/powerpc/include/asm/uaccess.h | 13 ++++++++-----
arch/powerpc/kernel/process.c | 2 +-
arch/powerpc/lib/sstep.c | 4 ++--
3 files changed, 11 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 15bea9a0f260..97faf0353919 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -47,13 +47,16 @@ static inline void set_fs(mm_segment_t fs)
* This check is sufficient because there is a large enough
* gap between user addresses and the kernel addresses
*/
-#define __access_ok(addr, size, segment) \
- (((addr) <= (segment).seg) && ((size) <= (segment).seg))
+static inline int __access_ok(int type, unsigned long addr, unsigned long size,
+ mm_segment_t seg)
+{
+ return addr <= seg.seg && size <= seg.seg;
+}
#else
-static inline int __access_ok(unsigned long addr, unsigned long size,
- mm_segment_t seg)
+static inline int __access_ok(int type, unsigned long addr, unsigned long size,
+ mm_segment_t seg)
{
if (addr > seg.seg)
return 0;
@@ -64,7 +67,7 @@ static inline int __access_ok(unsigned long addr, unsigned long size,
#define access_ok(type, addr, size) \
(__chk_user_ptr(addr), \
- __access_ok((__force unsigned long)(addr), (size), get_fs()))
+ __access_ok((type), (__force unsigned long)(addr), (size), get_fs()))
/*
* These are the main single-value transfer routines. They automatically
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 7ad304a3cc7d..4cc84fe13f9c 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1310,7 +1310,7 @@ void show_user_instructions(struct pt_regs *regs)
* Make sure the NIP points at userspace, not kernel text/data or
* elsewhere.
*/
- if (!__access_ok(pc, NR_INSN_TO_PRINT * sizeof(int), USER_DS)) {
+ if (!__access_ok(VERIFY_READ, pc, NR_INSN_TO_PRINT * sizeof(int), USER_DS)) {
pr_info("%s[%d]: Bad NIP, not dumping instructions.\n",
current->comm, current->pid);
return;
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index d81568f783e5..ff117418257c 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -110,9 +110,9 @@ static nokprobe_inline long address_ok(struct pt_regs *regs,
{
if (!user_mode(regs))
return 1;
- if (__access_ok(ea, nb, USER_DS))
+ if (__access_ok(VERIFY_WRITE, ea, nb, USER_DS))
return 1;
- if (__access_ok(ea, 1, USER_DS))
+ if (__access_ok(VERIFY_WRITE, ea, 1, USER_DS))
/* Access overlaps the end of the user region */
regs->dar = USER_DS.seg;
else
--
2.13.3
reply other threads:[~2018-10-18 9:40 UTC|newest]
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