* [PATCH][next] tipc: Use size_add() in calls to struct_size()
@ 2023-09-15 19:16 Gustavo A. R. Silva
2023-09-15 19:43 ` Kees Cook
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2023-09-15 19:16 UTC (permalink / raw)
To: Jon Maloy, Ying Xue, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Gustavo A. R. Silva
Cc: netdev, tipc-discussion, linux-kernel, Gustavo A. R. Silva,
linux-hardening
If, for any reason, the open-coded arithmetic causes a wraparound,
the protection that `struct_size()` adds against potential integer
overflows is defeated. Fix this by hardening call to `struct_size()`
with `size_add()`.
Fixes: e034c6d23bc4 ("tipc: Use struct_size() helper")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
net/tipc/link.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/tipc/link.c b/net/tipc/link.c
index e33b4f29f77c..d0143823658d 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -1446,7 +1446,7 @@ u16 tipc_get_gap_ack_blks(struct tipc_gap_ack_blks **ga, struct tipc_link *l,
p = (struct tipc_gap_ack_blks *)msg_data(hdr);
sz = ntohs(p->len);
/* Sanity check */
- if (sz == struct_size(p, gacks, p->ugack_cnt + p->bgack_cnt)) {
+ if (sz == struct_size(p, gacks, size_add(p->ugack_cnt, p->bgack_cnt))) {
/* Good, check if the desired type exists */
if ((uc && p->ugack_cnt) || (!uc && p->bgack_cnt))
goto ok;
@@ -1533,7 +1533,7 @@ static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr)
__tipc_build_gap_ack_blks(ga, l, ga->bgack_cnt) : 0;
/* Total len */
- len = struct_size(ga, gacks, ga->bgack_cnt + ga->ugack_cnt);
+ len = struct_size(ga, gacks, size_add(ga->bgack_cnt, ga->ugack_cnt));
ga->len = htons(len);
return len;
}
--
2.34.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH][next] tipc: Use size_add() in calls to struct_size()
2023-09-15 19:16 [PATCH][next] tipc: Use size_add() in calls to struct_size() Gustavo A. R. Silva
@ 2023-09-15 19:43 ` Kees Cook
0 siblings, 0 replies; 2+ messages in thread
From: Kees Cook @ 2023-09-15 19:43 UTC (permalink / raw)
To: Gustavo A. R. Silva
Cc: Jon Maloy, Ying Xue, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, netdev, tipc-discussion,
linux-kernel, linux-hardening
On Fri, Sep 15, 2023 at 01:16:26PM -0600, Gustavo A. R. Silva wrote:
> If, for any reason, the open-coded arithmetic causes a wraparound,
> the protection that `struct_size()` adds against potential integer
> overflows is defeated. Fix this by hardening call to `struct_size()`
> with `size_add()`.
>
> Fixes: e034c6d23bc4 ("tipc: Use struct_size() helper")
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
^ permalink raw reply [flat|nested] 2+ messages in thread
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