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authorEric Dumazet <edumazet@google.com>2023-02-17 21:24:54 +0300
committerDavid S. Miller <davem@davemloft.net>2023-02-20 14:39:59 +0300
commit5f1eb1ff58ea122e24adf0bc940f268ed2227462 (patch)
tree9e570cd6d4c78167faf5aa6a2b5f618ff093046b /net/core
parentfce10282a03db59bdb1cba6333d0564461d47bd6 (diff)
downloadlinux-5f1eb1ff58ea122e24adf0bc940f268ed2227462.tar.xz
scm: add user copy checks to put_cmsg()
This is a followup of commit 2558b8039d05 ("net: use a bounce buffer for copying skb->mark") x86 and powerpc define user_access_begin, meaning that they are not able to perform user copy checks when using user_write_access_begin() / unsafe_copy_to_user() and friends [1] Instead of waiting bugs to trigger on other arches, add a check_object_size() in put_cmsg() to make sure that new code tested on x86 with CONFIG_HARDENED_USERCOPY=y will perform more security checks. [1] We can not generically call check_object_size() from unsafe_copy_to_user() because UACCESS is enabled at this point. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Kees Cook <keescook@chromium.org> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/scm.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/core/scm.c b/net/core/scm.c
index 5c356f0dee30..acb7d776fa6e 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -229,6 +229,8 @@ int put_cmsg(struct msghdr * msg, int level, int type, int len, void *data)
if (msg->msg_control_is_user) {
struct cmsghdr __user *cm = msg->msg_control_user;
+ check_object_size(data, cmlen - sizeof(*cm), true);
+
if (!user_write_access_begin(cm, cmlen))
goto efault;