compat breakage in preadv() and pwritev()
Fix for a dumb preadv()/pwritev() compat bug - unlike the native
variants, compat_... ones forget to check FMODE_P{READ,WRITE}, so e.g.
on pipe the native preadv() will fail with -ESPIPE and compat one will
act as readv() and succeed. Not critical, but it's a clear bug with trivial
fix.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/compat.c b/fs/compat.c
index f6fd0a0..691c3fd 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1228,7 +1228,9 @@
file = fget_light(fd, &fput_needed);
if (!file)
return -EBADF;
- ret = compat_readv(file, vec, vlen, &pos);
+ ret = -ESPIPE;
+ if (file->f_mode & FMODE_PREAD)
+ ret = compat_readv(file, vec, vlen, &pos);
fput_light(file, fput_needed);
return ret;
}
@@ -1285,7 +1287,9 @@
file = fget_light(fd, &fput_needed);
if (!file)
return -EBADF;
- ret = compat_writev(file, vec, vlen, &pos);
+ ret = -ESPIPE;
+ if (file->f_mode & FMODE_PWRITE)
+ ret = compat_writev(file, vec, vlen, &pos);
fput_light(file, fput_needed);
return ret;
}