On 11/6/2025 2:28 PM, Nate Karstens wrote:
The `len` member of the sk_buff is an unsigned int. This is cast to `ssize_t` (a signed type) for the first sk_buff in the comparison, but not the second sk_buff. On 32-bit systems, this can result in an integer underflow for certain values because unsigned arithmetic is being used.
This appears to be an oversight: if the intention was to use unsigned arithmetic, then the first cast would have been omitted. The change ensures both len values are cast to `ssize_t`.
The underflow causes an issue with ktls when multiple TLS PDUs are included in a single TCP segment. The mainline kernel does not use strparser for ktls anymore, but this is still useful for other features that still use strparser, and for backporting.
Signed-off-by: Nate Karstens nate.karstens@garmin.com Cc: stable@vger.kernel.org Fixes: 43a0c6751a32 ("strparser: Stream parser for messages")
Reviewed-by: Jacob Keller jacob.e.keller@intel.com
net/strparser/strparser.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/strparser/strparser.c b/net/strparser/strparser.c index 43b1f558b33d..e659fea2da70 100644 --- a/net/strparser/strparser.c +++ b/net/strparser/strparser.c @@ -238,7 +238,7 @@ static int __strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb, strp_parser_err(strp, -EMSGSIZE, desc); break; } else if (len <= (ssize_t)head->len -
skb->len - stm->strp.offset) {
(ssize_t)skb->len - stm->strp.offset) { /* Length must be into new skb (and also * greater than zero) */