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Commit c44ed965 authored by Al Viro's avatar Al Viro Committed by Linus Torvalds
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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: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c9a816c0

fs/compat.c

+6 −2
Original line number Diff line number Diff line
@@ -1228,6 +1228,8 @@ compat_sys_preadv(unsigned long fd, const struct compat_iovec __user *vec, 
	file = fget_light(fd, &fput_needed);

	if (!file)

		return -EBADF;

	ret = -ESPIPE;

	if (file->f_mode & FMODE_PREAD)

		ret = compat_readv(file, vec, vlen, &pos);

	fput_light(file, fput_needed);

	return ret;
@@ -1285,6 +1287,8 @@ compat_sys_pwritev(unsigned long fd, const struct compat_iovec __user *vec, 
	file = fget_light(fd, &fput_needed);

	if (!file)

		return -EBADF;

	ret = -ESPIPE;

	if (file->f_mode & FMODE_PWRITE)

		ret = compat_writev(file, vec, vlen, &pos);

	fput_light(file, fput_needed);

	return ret;