| Message ID | 20210902190400.5257-1-paskripkin@gmail.com (mailing list archive) |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: xfrm: fix shift-out-of-bounds in xfrm_get_default | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Guessed tree name to be net-next |
| netdev/subject_prefix | warning | Target tree name not specified in the subject |
| netdev/cc_maintainers | fail | 2 blamed authors not CCed: christian.langrock@secunet.com antony.antony@secunet.com; 2 maintainers not CCed: christian.langrock@secunet.com antony.antony@secunet.com |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 14 this patch: 14 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 11 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 14 this patch: 14 |
| netdev/header_inline | success | Link |
On Thu, Sep 02, 2021 at 10:04:00PM +0300, Pavel Skripkin wrote: > Syzbot hit shift-out-of-bounds in xfrm_get_default. The problem was in > missing validation check for user data. > > up->dirmask comes from user-space, so we need to check if this value > is less than XFRM_USERPOLICY_DIRMASK_MAX to avoid shift-out-of-bounds bugs. > > Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy") > Reported-and-tested-by: syzbot+b2be9dd8ca6f6c73ee2d@syzkaller.appspotmail.com > Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> Applied, thanks Pavel!
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index b7b986520dc7..e4cf48c71315 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -2005,6 +2005,11 @@ static int xfrm_get_default(struct sk_buff *skb, struct nlmsghdr *nlh, return -EMSGSIZE; } + if (up->dirmask >= XFRM_USERPOLICY_DIRMASK_MAX) { + kfree_skb(r_skb); + return -EINVAL; + } + r_up = nlmsg_data(r_nlh); r_up->action = ((net->xfrm.policy_default & (1 << up->dirmask)) >> up->dirmask);
Syzbot hit shift-out-of-bounds in xfrm_get_default. The problem was in missing validation check for user data. up->dirmask comes from user-space, so we need to check if this value is less than XFRM_USERPOLICY_DIRMASK_MAX to avoid shift-out-of-bounds bugs. Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy") Reported-and-tested-by: syzbot+b2be9dd8ca6f6c73ee2d@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> --- net/xfrm/xfrm_user.c | 5 +++++ 1 file changed, 5 insertions(+)