From: Stacey Son <sson@FreeBSD.org>

Co-authored-by: Kyle Evans <kevans@FreeBSD.org>

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Kyle Evans <kevans@FreeBSD.org>
Signed-off-by: Karim Taha <kariem.taha2.7@gmail.com>
---
 bsd-user/bsd-mem.h            | 11 +++++++++++
 bsd-user/freebsd/os-syscall.c |  4 ++++
 2 files changed, 15 insertions(+)

diff --git a/bsd-user/bsd-mem.h b/bsd-user/bsd-mem.h
index a6446a454c..68d79ac080 100644
--- a/bsd-user/bsd-mem.h
+++ b/bsd-user/bsd-mem.h
@@ -89,4 +89,15 @@ static inline abi_long do_bsd_mprotect(abi_long arg1, abi_long arg2,
     return get_errno(target_mprotect(arg1, arg2, arg3));
 }
 
+/* msync(2) */
+static inline abi_long do_bsd_msync(abi_long addr, abi_long len, abi_long flags)
+{
+    if (!access_ok(VERIFY_WRITE, addr, len)) {
+        /* XXX Should be EFAULT, but FreeBSD seems to get this wrong. */
+        return -TARGET_ENOMEM;
+    }
+
+    return get_errno(msync(g2h_untagged(addr), len, flags));
+}
+
 #endif /* BSD_USER_BSD_MEM_H */
diff --git a/bsd-user/freebsd/os-syscall.c b/bsd-user/freebsd/os-syscall.c
index aea4e337ff..3871b15309 100644
--- a/bsd-user/freebsd/os-syscall.c
+++ b/bsd-user/freebsd/os-syscall.c
@@ -499,6 +499,10 @@ static abi_long freebsd_syscall(void *cpu_env, int num, abi_long arg1,
         ret = do_bsd_mprotect(arg1, arg2, arg3);
         break;
 
+    case TARGET_FREEBSD_NR_msync: /* msync(2) */
+        ret = do_bsd_msync(arg1, arg2, arg3);
+        break;
+
 #if defined(__FreeBSD_version) && __FreeBSD_version >= 1300048
     case TARGET_FREEBSD_NR_shm_open2: /* shm_open2(2) */
         ret = do_freebsd_shm_open2(arg1, arg2, arg3, arg4, arg5);
-- 
2.40.0

On 8/19/23 02:47, Karim Taha wrote:
> +static inline abi_long do_bsd_msync(abi_long addr, abi_long len, abi_long flags)
> +{
> +    if (!access_ok(VERIFY_WRITE, addr, len)) {

I think this check is wrong.  There's nothing in the kernel that requires writability, or 
even that the entire range be mapped.

I think you want guest_range_valid_untagged to simply check that the bounds are ok.

With that,
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>



r~