6.12-stable review patch. If anyone has any objections, please let me know.
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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) */