From c44ed965be7a84afaa07543c04eb97a5dfe93422 Mon Sep 17 00:00:00 2001 From: Al Viro 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 Signed-off-by: Linus Torvalds --- fs/compat.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/compat.c b/fs/compat.c index f6fd0a00e6c..691c3fd8ce1 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; } -- 2.39.2