diff mbox series

[net,v2,1/3] net/sched: cls_u32: No longer copy tcf_result on update to avoid use-after-free

Message ID 20230729123202.72406-2-jhs@mojatatu.com (mailing list archive)
State Accepted
Commit 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81
Delegated to: Netdev Maintainers
Headers show
Series net/sched Bind logic fixes for cls_fw, cls_u32 and cls_route | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1328 this patch: 1328
netdev/cc_maintainers fail 1 blamed authors not CCed: john.fastabend@gmail.com; 1 maintainers not CCed: john.fastabend@gmail.com
netdev/build_clang success Errors and warnings before: 1351 this patch: 1351
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 1351 this patch: 1351
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 7 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Jamal Hadi Salim July 29, 2023, 12:32 p.m. UTC 
From: valis <sec@valis.email>

When u32_change() is called on an existing filter, the whole
tcf_result struct is always copied into the new instance of the filter.

This causes a problem when updating a filter bound to a class,
as tcf_unbind_filter() is always called on the old instance in the
success path, decreasing filter_cnt of the still referenced class
and allowing it to be deleted, leading to a use-after-free.

Fix this by no longer copying the tcf_result struct from the old filter.

Fixes: de5df63228fc ("net: sched: cls_u32 changes to knode must appear atomic to readers")
Reported-by: valis <sec@valis.email>
Reported-by: M A Ramdhan <ramdhan@starlabs.sg>
Signed-off-by: valis <sec@valis.email>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
---
 net/sched/cls_u32.c | 1 -
 1 file changed, 1 deletion(-)
diff mbox series

Patch

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 907e58841fe8..da4c179a4d41 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -826,7 +826,6 @@  static struct tc_u_knode *u32_init_knode(struct net *net, struct tcf_proto *tp,
 
 	new->ifindex = n->ifindex;
 	new->fshift = n->fshift;
-	new->res = n->res;
 	new->flags = n->flags;
 	RCU_INIT_POINTER(new->ht_down, ht);