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[PATCH] Fix 32bit sendmsg() flaw

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When we copy 32bit ->msg_control contents to kernel, we walk the same
userland data twice without sanity checks on the second pass.

Second version of this patch: the original broke with 64-bit arches
running 32-bit-compat-mode executables doing sendmsg() syscalls with
unaligned CMSG data areas

Another thing is that we use kmalloc() to allocate and sock_kfree_s()
to free afterwards; less serious, but also needs fixing.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Al Viro
2005-09-07 18:28:51 -07:00
committed by Linus Torvalds
parent 5aa3b610a7
commit 8920e8f94c
3 changed files with 29 additions and 20 deletions
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3
net/socket.c
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@ -1745,10 +1745,11 @@ asmlinkage long sys_sendmsg(int fd, struct msghdr __user *msg, unsigned flags)
goto out_freeiov;
ctl_len = msg_sys.msg_controllen;
if ((MSG_CMSG_COMPAT & flags) && ctl_len) {
err = cmsghdr_from_user_compat_to_kern(&msg_sys, ctl, sizeof(ctl));
err = cmsghdr_from_user_compat_to_kern(&msg_sys, sock->sk, ctl, sizeof(ctl));
if (err)
goto out_freeiov;
ctl_buf = msg_sys.msg_control;
ctl_len = msg_sys.msg_controllen;
} else if (ctl_len) {
if (ctl_len > sizeof(ctl))
{