From 767b68e96993e29e3480d7ecdd9c4b84667c5762 Mon Sep 17 00:00:00 2001 From: Dan Rosenberg Date: Wed, 22 Sep 2010 14:32:56 -0400 Subject: [PATCH] Prevent freeing uninitialized pointer in compat_do_readv_writev In 32-bit compatibility mode, the error handling for compat_do_readv_writev() may free an uninitialized pointer, potentially leading to all sorts of ugly memory corruption. This is reliably triggerable by unprivileged users by invoking the readv()/writev() syscalls with an invalid iovec pointer. The below patch fixes this to emulate the non-compat version. Introduced by commit b83733639a49 ("compat: factor out compat_rw_copy_check_uvector from compat_do_readv_writev") Signed-off-by: Dan Rosenberg Cc: stable@kernel.org (2.6.35) Cc: Al Viro Signed-off-by: Linus Torvalds --- fs/compat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/compat.c b/fs/compat.c index 718c7062aec1..0644a154672b 100644 --- a/fs/compat.c +++ b/fs/compat.c @@ -1153,7 +1153,7 @@ static ssize_t compat_do_readv_writev(int type, struct file *file, { compat_ssize_t tot_len; struct iovec iovstack[UIO_FASTIOV]; - struct iovec *iov; + struct iovec *iov = iovstack; ssize_t ret; io_fn_t fn; iov_fn_t fnv;