[PATCH v3 26/27] COMPAT: add get/put_compat_rlimit

[Jiri Slaby <jslaby@suse.cz>]

Extract those functions from compat_sys_[gs]etrlimit for later
use with newly added rlimit syscalls.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: James Morris <jmorris@namei.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
---
 kernel/compat.c |   61 ++++++++++++++++++++++++++++++++++++-------------------
 1 files changed, 40 insertions(+), 21 deletions(-)

diff --git a/kernel/compat.c b/kernel/compat.c
index f6c204f..af15719 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -274,6 +274,39 @@ asmlinkage long compat_sys_sigprocmask(int how, compat_old_sigset_t __user *set,
 	return ret;
 }
 
+static int get_compat_rlimit(struct rlimit *dst,
+		const struct compat_rlimit __user *src)
+{
+	if (!access_ok(VERIFY_READ, src, sizeof(*src)) ||
+			__get_user(dst->rlim_cur, &src->rlim_cur) ||
+			__get_user(dst->rlim_max, &src->rlim_max))
+		return -EFAULT;
+
+	if (dst->rlim_cur == COMPAT_RLIM_INFINITY)
+		dst->rlim_cur = RLIM_INFINITY;
+	if (dst->rlim_max == COMPAT_RLIM_INFINITY)
+		dst->rlim_max = RLIM_INFINITY;
+	return 0;
+}
+
+static int put_compat_rlimit(const struct rlimit *src,
+		struct compat_rlimit __user *dst)
+{
+	struct rlimit r = *src;
+
+	if (r.rlim_cur > COMPAT_RLIM_INFINITY)
+		r.rlim_cur = COMPAT_RLIM_INFINITY;
+	if (r.rlim_max > COMPAT_RLIM_INFINITY)
+		r.rlim_max = COMPAT_RLIM_INFINITY;
+
+	if (!access_ok(VERIFY_WRITE, dst, sizeof(*dst)) ||
+	    __put_user(r.rlim_cur, &dst->rlim_cur) ||
+	    __put_user(r.rlim_max, &dst->rlim_max))
+		return -EFAULT;
+
+	return 0;
+}
+
 asmlinkage long compat_sys_setrlimit(unsigned int resource,
 		struct compat_rlimit __user *rlim)
 {
@@ -284,17 +317,12 @@ asmlinkage long compat_sys_setrlimit(unsigned int resource,
 	if (resource >= RLIM_NLIMITS)
 		return -EINVAL;
 
-	if (!access_ok(VERIFY_READ, rlim, sizeof(*rlim)) ||
-	    __get_user(r.rlim_cur, &rlim->rlim_cur) ||
-	    __get_user(r.rlim_max, &rlim->rlim_max))
-		return -EFAULT;
+	ret = get_compat_rlimit(&r, rlim);
+	if (ret)
+		return ret;
 
-	if (r.rlim_cur == COMPAT_RLIM_INFINITY)
-		r.rlim_cur = RLIM_INFINITY;
-	if (r.rlim_max == COMPAT_RLIM_INFINITY)
-		r.rlim_max = RLIM_INFINITY;
 	set_fs(KERNEL_DS);
-	ret = sys_setrlimit(resource, (struct rlimit __user *) &r);
+	ret = sys_setrlimit(resource, (struct rlimit __force __user *)&r);
 	set_fs(old_fs);
 	return ret;
 }
@@ -336,19 +364,10 @@ asmlinkage long compat_sys_getrlimit (unsigned int resource,
 	mm_segment_t old_fs = get_fs();
 
 	set_fs(KERNEL_DS);
-	ret = sys_getrlimit(resource, (struct rlimit __user *) &r);
+	ret = sys_getrlimit(resource, (struct rlimit __force __user *)&r);
 	set_fs(old_fs);
-	if (!ret) {
-		if (r.rlim_cur > COMPAT_RLIM_INFINITY)
-			r.rlim_cur = COMPAT_RLIM_INFINITY;
-		if (r.rlim_max > COMPAT_RLIM_INFINITY)
-			r.rlim_max = COMPAT_RLIM_INFINITY;
-
-		if (!access_ok(VERIFY_WRITE, rlim, sizeof(*rlim)) ||
-		    __put_user(r.rlim_cur, &rlim->rlim_cur) ||
-		    __put_user(r.rlim_max, &rlim->rlim_max))
-			return -EFAULT;
-	}
+	if (!ret)
+		ret = put_compat_rlimit(&r, rlim);
 	return ret;
 }
 
-- 
1.6.5.3