[src/trunk]: src/sys/arch/macppc/dev Use old limit of 32 + 32 bytes to keep c...

[mlelstv <mlelstv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/813c3ba6506c
branches:  trunk
changeset: 368221:813c3ba6506c
user:      mlelstv <mlelstv%NetBSD.org@localhost>
date:      Wed Jun 29 17:59:40 2022 +0000

description:
Use old limit of 32 + 32 bytes to keep combining buffer on stack.
There are no devices on this platform that need more and for larger
values, the driver should be better rewritten.

diffstat:

 sys/arch/macppc/dev/ki2c.c |  14 ++++++++++++--
 1 files changed, 12 insertions(+), 2 deletions(-)

diffs (42 lines):

diff -r 0fed3f1f1462 -r 813c3ba6506c sys/arch/macppc/dev/ki2c.c
--- a/sys/arch/macppc/dev/ki2c.c        Wed Jun 29 16:33:09 2022 +0000
+++ b/sys/arch/macppc/dev/ki2c.c        Wed Jun 29 17:59:40 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ki2c.c,v 1.32 2021/08/07 16:18:57 thorpej Exp $        */
+/*     $NetBSD: ki2c.c,v 1.33 2022/06/29 17:59:40 mlelstv Exp $        */
 /*     Id: ki2c.c,v 1.7 2002/10/05 09:56:05 tsubai Exp */
 
 /*-
@@ -44,6 +44,9 @@
 #define DPRINTF while (0) printf
 #endif
 
+#define KI2C_EXEC_MAX_CMDLEN   32
+#define KI2C_EXEC_MAX_BUFLEN   32
+
 int ki2c_match(device_t, cfdata_t, void *);
 void ki2c_attach(device_t, device_t, void *);
 inline uint8_t ki2c_readreg(struct ki2c_softc *, int);
@@ -393,7 +396,7 @@
        int i;
        size_t w_len;
        uint8_t *wp;
-       uint8_t wrbuf[I2C_EXEC_MAX_CMDLEN + I2C_EXEC_MAX_CMDLEN];
+       uint8_t wrbuf[KI2C_EXEC_MAX_CMDLEN + KI2C_EXEC_MAX_CMDLEN];
        uint8_t channel;
 
        /*
@@ -404,6 +407,13 @@
        if (cmdlen == 0 && buflen == 0)
                return -1;
 
+       /*
+        * Transaction could be much larger now. Bail if it exceeds our
+        * small combining buffer, we don't expect such devices.
+        */
+       if (cmdlen + buflen > sizeof(wrbuf))
+               return -1;
+
        channel = (addr & 0xf80) ? 0x10 : 0x00;
        addr &= 0x7f;