From 586ce098a23b6ab7383df853a84ae3d48dc889aa Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 13 Mar 2011 01:50:58 -0500 Subject: [PATCH] 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 --- 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; } -- 2.20.1