diff options
| author | Jiayuan Chen <jiayuan.chen@shopee.com> | 2026-03-09 15:39:16 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-03-11 05:39:35 +0300 |
| commit | 34bd3c6b0bd383a76d987c8c45c4f309b681b255 (patch) | |
| tree | 04a6399f04e1e115248aeace674bd128efd45333 | |
| parent | 9278b888920ee8f3cea06622f04da681536b6601 (diff) | |
| download | linux-34bd3c6b0bd383a76d987c8c45c4f309b681b255.tar.xz | |
net: sched: cls_u32: Avoid memcpy() false-positive warning in u32_init_knode()
Syzbot reported a warning in u32_init_knode() [1].
Similar to commit 7cba18332e36 ("net: sched: cls_u32: Avoid memcpy()
false-positive warning") which addressed the same issue in u32_change(),
use unsafe_memcpy() in u32_init_knode() to work around the compiler's
inability to see into composite flexible array structs.
This silences the false-positive reported by syzbot:
memcpy: detected field-spanning write (size 32) of single field
"&new->sel" at net/sched/cls_u32.c:855 (size 16)
Since the memory is correctly allocated with kzalloc_flex() using
s->nkeys, this is purely a false positive and does not need a Fixes tag.
[1] https://syzkaller.appspot.com/bug?extid=d5ace703ed883df56e42
Reported-by: syzbot+d5ace703ed883df56e42@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/69a811b9.a70a0220.b118c.0019.GAE@google.com/T/
Reviewed-by: Simon Horman <horms@kernel.org>
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com>
Link: https://patch.msgid.link/20260309123917.402183-1-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/sched/cls_u32.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c index 9241c025aa74..8f30cc82181d 100644 --- a/net/sched/cls_u32.c +++ b/net/sched/cls_u32.c @@ -852,7 +852,10 @@ static struct tc_u_knode *u32_init_knode(struct net *net, struct tcf_proto *tp, /* Similarly success statistics must be moved as pointers */ new->pcpu_success = n->pcpu_success; #endif - memcpy(&new->sel, s, struct_size(s, keys, s->nkeys)); + unsafe_memcpy(&new->sel, s, struct_size(s, keys, s->nkeys), + /* A composite flex-array structure destination, + * which was correctly sized with kzalloc_flex(), + * above. */); if (tcf_exts_init(&new->exts, net, TCA_U32_ACT, TCA_U32_POLICE)) { kfree(new); |