| From 4da4e4bde1c453ac5cc2dce5def81d504ae257ee Mon Sep 17 00:00:00 2001 |
| From: Nate Karstens <nate.karstens@garmin.com> |
| Date: Thu, 6 Nov 2025 16:28:33 -0600 |
| Subject: strparser: Fix signed/unsigned mismatch bug |
| |
| From: Nate Karstens <nate.karstens@garmin.com> |
| |
| commit 4da4e4bde1c453ac5cc2dce5def81d504ae257ee upstream. |
| |
| 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> |
| Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> |
| Link: https://patch.msgid.link/20251106222835.1871628-1-nate.karstens@garmin.com |
| Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/strparser/strparser.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/net/strparser/strparser.c |
| +++ b/net/strparser/strparser.c |
| @@ -238,7 +238,7 @@ static int __strp_recv(read_descriptor_t |
| 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) |
| */ |
