|
 |
12e66bb |
From: Peter Maydell <peter.maydell@linaro.org>
|
|
|
12e66bb |
Date: Tue, 8 Jan 2019 18:49:00 +0000
|
|
|
12e66bb |
Subject: [PATCH] linux-user: make pwrite64/pread64(fd, NULL, 0, offset) return
|
|
|
12e66bb |
0
|
|
|
12e66bb |
MIME-Version: 1.0
|
|
|
12e66bb |
Content-Type: text/plain; charset=UTF-8
|
|
|
12e66bb |
Content-Transfer-Encoding: 8bit
|
|
|
12e66bb |
|
|
|
12e66bb |
Linux returns success if pwrite64() or pread64() are called with a
|
|
|
12e66bb |
zero length NULL buffer, but QEMU was returning -TARGET_EFAULT.
|
|
|
12e66bb |
|
|
|
12e66bb |
This is the same bug that we fixed in commit 58cfa6c2e6eb51b23cc9
|
|
|
12e66bb |
for the write syscall, and long before that in 38d840e6790c29f59
|
|
|
12e66bb |
for the read syscall.
|
|
|
12e66bb |
|
|
|
12e66bb |
Fixes: https://bugs.launchpad.net/qemu/+bug/1810433
|
|
|
12e66bb |
|
|
|
12e66bb |
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
|
|
|
12e66bb |
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
|
|
|
12e66bb |
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
|
|
|
12e66bb |
Message-Id: <20190108184900.9654-1-peter.maydell@linaro.org>
|
|
|
12e66bb |
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
|
|
|
12e66bb |
(cherry picked from commit 2bd3f8998e1e7dcd9afc29fab252fb9936f9e956)
|
|
|
12e66bb |
---
|
|
|
12e66bb |
linux-user/syscall.c | 22 ++++++++++++++++++----
|
|
|
12e66bb |
1 file changed, 18 insertions(+), 4 deletions(-)
|
|
|
12e66bb |
|
|
|
12e66bb |
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
|
|
|
12e66bb |
index 280137da8c..b13a170e52 100644
|
|
|
12e66bb |
--- a/linux-user/syscall.c
|
|
|
12e66bb |
+++ b/linux-user/syscall.c
|
|
|
12e66bb |
@@ -9677,8 +9677,15 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
|
|
|
12e66bb |
arg4 = arg5;
|
|
|
12e66bb |
arg5 = arg6;
|
|
|
12e66bb |
}
|
|
|
12e66bb |
- if (!(p = lock_user(VERIFY_WRITE, arg2, arg3, 0)))
|
|
|
12e66bb |
- return -TARGET_EFAULT;
|
|
|
12e66bb |
+ if (arg2 == 0 && arg3 == 0) {
|
|
|
12e66bb |
+ /* Special-case NULL buffer and zero length, which should succeed */
|
|
|
12e66bb |
+ p = 0;
|
|
|
12e66bb |
+ } else {
|
|
|
12e66bb |
+ p = lock_user(VERIFY_WRITE, arg2, arg3, 0);
|
|
|
12e66bb |
+ if (!p) {
|
|
|
12e66bb |
+ return -TARGET_EFAULT;
|
|
|
12e66bb |
+ }
|
|
|
12e66bb |
+ }
|
|
|
12e66bb |
ret = get_errno(pread64(arg1, p, arg3, target_offset64(arg4, arg5)));
|
|
|
12e66bb |
unlock_user(p, arg2, ret);
|
|
|
12e66bb |
return ret;
|
|
|
12e66bb |
@@ -9687,8 +9694,15 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
|
|
|
12e66bb |
arg4 = arg5;
|
|
|
12e66bb |
arg5 = arg6;
|
|
|
12e66bb |
}
|
|
|
12e66bb |
- if (!(p = lock_user(VERIFY_READ, arg2, arg3, 1)))
|
|
|
12e66bb |
- return -TARGET_EFAULT;
|
|
|
12e66bb |
+ if (arg2 == 0 && arg3 == 0) {
|
|
|
12e66bb |
+ /* Special-case NULL buffer and zero length, which should succeed */
|
|
|
12e66bb |
+ p = 0;
|
|
|
12e66bb |
+ } else {
|
|
|
12e66bb |
+ p = lock_user(VERIFY_READ, arg2, arg3, 1);
|
|
|
12e66bb |
+ if (!p) {
|
|
|
12e66bb |
+ return -TARGET_EFAULT;
|
|
|
12e66bb |
+ }
|
|
|
12e66bb |
+ }
|
|
|
12e66bb |
ret = get_errno(pwrite64(arg1, p, arg3, target_offset64(arg4, arg5)));
|
|
|
12e66bb |
unlock_user(p, arg2, 0);
|
|
|
12e66bb |
return ret;
|