Commit 61ab751451f5 for kernel
commit 61ab751451f5ebd0b98e02276a44e23a10110402
Author: Dan Carpenter <dan.carpenter@linaro.org>
Date: Wed Jul 24 11:08:18 2024 -0500
mISDN: Fix a use after free in hfcmulti_tx()
Don't dereference *sp after calling dev_kfree_skb(*sp).
Fixes: af69fb3a8ffa ("Add mISDN HFC multiport driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/8be65f5a-c2dd-4ba0-8a10-bfe5980b8cfb@stanley.mountain
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
diff --git a/drivers/isdn/hardware/mISDN/hfcmulti.c b/drivers/isdn/hardware/mISDN/hfcmulti.c
index 0d2928d8aeae..e5a483fd9ad8 100644
--- a/drivers/isdn/hardware/mISDN/hfcmulti.c
+++ b/drivers/isdn/hardware/mISDN/hfcmulti.c
@@ -1901,7 +1901,7 @@ hfcmulti_dtmf(struct hfc_multi *hc)
static void
hfcmulti_tx(struct hfc_multi *hc, int ch)
{
- int i, ii, temp, len = 0;
+ int i, ii, temp, tmp_len, len = 0;
int Zspace, z1, z2; /* must be int for calculation */
int Fspace, f1, f2;
u_char *d;
@@ -2122,14 +2122,15 @@ hfcmulti_tx(struct hfc_multi *hc, int ch)
HFC_wait_nodebug(hc);
}
+ tmp_len = (*sp)->len;
dev_kfree_skb(*sp);
/* check for next frame */
if (bch && get_next_bframe(bch)) {
- len = (*sp)->len;
+ len = tmp_len;
goto next_frame;
}
if (dch && get_next_dframe(dch)) {
- len = (*sp)->len;
+ len = tmp_len;
goto next_frame;
}