2018-04-11 03:38:56

by Laura Abbott

Subject: [PATCHv2] mISDN: Remove VLAs

There's an ongoing effort to remove VLAs[1] from the kernel to eventually
turn on -Wvla. Remove the VLAs from the mISDN code by switching to using
kstrdup in one place and using an upper bound in another.

Signed-off-by: Laura Abbott <[email protected]>
---
v2: Switch to a tighter upper bound so we are allocating a more
reasonable amount on the stack (300). This is based on previous checks
against this value.
---
drivers/isdn/mISDN/dsp_hwec.c | 8 +++++---
drivers/isdn/mISDN/l1oip_core.c | 14 +++++++++++---
2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/isdn/mISDN/dsp_hwec.c b/drivers/isdn/mISDN/dsp_hwec.c
index a6e87076acc2..5336bbdbfdc5 100644
--- a/drivers/isdn/mISDN/dsp_hwec.c
+++ b/drivers/isdn/mISDN/dsp_hwec.c
@@ -68,12 +68,12 @@ void dsp_hwec_enable(struct dsp *dsp, const char *arg)
goto _do;

{
- char _dup[len + 1];
char *dup, *tok, *name, *val;
int tmp;

- strcpy(_dup, arg);
- dup = _dup;
+ dup = kstrdup(arg, GFP_ATOMIC);
+ if (!dup)
+ return;

while ((tok = strsep(&dup, ","))) {
if (!strlen(tok))
@@ -89,6 +89,8 @@ void dsp_hwec_enable(struct dsp *dsp, const char *arg)
deftaps = tmp;
}
}
+
+ kfree(dup);
}

_do:
diff --git a/drivers/isdn/mISDN/l1oip_core.c b/drivers/isdn/mISDN/l1oip_core.c
index 21d50e4cc5e1..b05022f94f18 100644
--- a/drivers/isdn/mISDN/l1oip_core.c
+++ b/drivers/isdn/mISDN/l1oip_core.c
@@ -279,7 +279,7 @@ l1oip_socket_send(struct l1oip *hc, u8 localcodec, u8 channel, u32 chanmask,
u16 timebase, u8 *buf, int len)
{
u8 *p;
- u8 frame[len + 32];
+ u8 frame[MAX_DFRAME_LEN_L1 + 32];
struct socket *socket = NULL;

if (debug & DEBUG_L1OIP_MSG)
@@ -902,7 +902,11 @@ handle_dmsg(struct mISDNchannel *ch, struct sk_buff *skb)
p = skb->data;
l = skb->len;
while (l) {
- ll = (l < L1OIP_MAX_PERFRAME) ? l : L1OIP_MAX_PERFRAME;
+ /*
+ * This is technically bounded by L1OIP_MAX_PERFRAME but
+ * MAX_DFRAME_LEN_L1 < L1OIP_MAX_PERFRAME
+ */
+ ll = (l < MAX_DFRAME_LEN_L1) ? l : MAX_DFRAME_LEN_L1;
l1oip_socket_send(hc, 0, dch->slot, 0,
hc->chan[dch->slot].tx_counter++, p, ll);
p += ll;
@@ -1140,7 +1144,11 @@ handle_bmsg(struct mISDNchannel *ch, struct sk_buff *skb)
p = skb->data;
l = skb->len;
while (l) {
- ll = (l < L1OIP_MAX_PERFRAME) ? l : L1OIP_MAX_PERFRAME;
+ /*
+ * This is technically bounded by L1OIP_MAX_PERFRAME but
+ * MAX_DFRAME_LEN_L1 < L1OIP_MAX_PERFRAME
+ */
+ ll = (l < MAX_DFRAME_LEN_L1) ? l : MAX_DFRAME_LEN_L1;
l1oip_socket_send(hc, hc->codec, bch->slot, 0,
hc->chan[bch->slot].tx_counter, p, ll);
hc->chan[bch->slot].tx_counter += ll;
--
2.14.3

2018-04-13 03:01:53

by David Miller

Subject: Re: [PATCHv2] mISDN: Remove VLAs

From: Laura Abbott <[email protected]>
Date: Tue, 10 Apr 2018 18:04:29 -0700

> There's an ongoing effort to remove VLAs[1] from the kernel to eventually
> turn on -Wvla. Remove the VLAs from the mISDN code by switching to using
> kstrdup in one place and using an upper bound in another.
>
> Signed-off-by: Laura Abbott <[email protected]>
> ---
> v2: Switch to a tighter upper bound so we are allocating a more
> reasonable amount on the stack (300). This is based on previous checks
> against this value.

Applied.