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>
This commit is contained in:
Al Viro 2011-03-13 23:24:46 +00:00 committed by Linus Torvalds
parent c9a816c0ec
commit c44ed965be

View File

@ -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;
}