From c44ed965be7a84afaa07543c04eb97a5dfe93422 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@ZenIV.linux.org.uk>
Date: Sun, 13 Mar 2011 23:24:46 +0000
Subject: [PATCH] compat breakage in preadv() and pwritev()
Fix for a dumb preadv()/pwritev() compat bug - unlike the native
variants, the 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, so IMO it's OK for
-final.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/compat.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/fs/compat.c b/fs/compat.c
index f6fd0a00e6cc..691c3fd8ce1d 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1228,7 +1228,9 @@ compat_sys_preadv(unsigned long fd, const struct compat_iovec __user *vec,
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 @@ compat_sys_pwritev(unsigned long fd, const struct compat_iovec __user *vec,
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;
}
--
GitLab