Dynamic static allocation is evil, as Kernel stack is too low, and
compilation complains about it on some archs:

        drivers/media/dvb-frontends/bcm3510.c:230:1: warning: 
'bcm3510_do_hab_cmd' uses dynamic stack allocation [enabled by default]
        drivers/media/dvb-frontends/itd1000.c:69:1: warning: 
'itd1000_write_regs.constprop.0' uses dynamic stack allocation [enabled by 
default]
        drivers/media/dvb-frontends/mt312.c:126:1: warning: 'mt312_write' uses 
dynamic stack allocation [enabled by default]
        drivers/media/dvb-frontends/nxt200x.c:111:1: warning: 
'nxt200x_writebytes' uses dynamic stack allocation [enabled by default]
        drivers/media/dvb-frontends/stb6100.c:216:1: warning: 
'stb6100_write_reg_range.constprop.3' uses dynamic stack allocation [enabled by 
default]
        drivers/media/dvb-frontends/stv6110.c:98:1: warning: 
'stv6110_write_regs' uses dynamic stack allocation [enabled by default]
        drivers/media/dvb-frontends/stv6110x.c:85:1: warning: 
'stv6110x_write_regs' uses dynamic stack allocation [enabled by default]
        drivers/media/dvb-frontends/tda18271c2dd.c:147:1: warning: 'WriteRegs' 
uses dynamic stack allocation [enabled by default]
        drivers/media/dvb-frontends/zl10039.c:119:1: warning: 'zl10039_write' 
uses dynamic stack allocation [enabled by default]

Instead, let's enforce a limit for the buffer. Considering that I2C
transfers are generally limited, and that devices used on USB has a
max data length of 80, it seem safe to use 80 as the hard limit for all
those devices. On most cases, the limit is a way lower than that, but
80 is small enough to not affect the Kernel stack, and it is a no brain
limit, as using smaller ones would require to either carefully each
driver or to take a look on each datasheet.

Signed-off-by: Mauro Carvalho Chehab <m.che...@samsung.com>
---
 drivers/media/dvb-frontends/bcm3510.c      | 12 +++++++++++-
 drivers/media/dvb-frontends/itd1000.c      | 10 +++++++++-
 drivers/media/dvb-frontends/mt312.c        |  8 +++++++-
 drivers/media/dvb-frontends/nxt200x.c      |  8 +++++++-
 drivers/media/dvb-frontends/stb6100.c      |  9 ++++++++-
 drivers/media/dvb-frontends/stv6110.c      |  9 ++++++++-
 drivers/media/dvb-frontends/stv6110x.c     |  9 ++++++++-
 drivers/media/dvb-frontends/tda18271c2dd.c | 11 +++++++++--
 drivers/media/dvb-frontends/zl10039.c      |  9 ++++++++-
 9 files changed, 75 insertions(+), 10 deletions(-)

diff --git a/drivers/media/dvb-frontends/bcm3510.c 
b/drivers/media/dvb-frontends/bcm3510.c
index 1b77909c0c71..efd8ce671caf 100644
--- a/drivers/media/dvb-frontends/bcm3510.c
+++ b/drivers/media/dvb-frontends/bcm3510.c
@@ -201,9 +201,19 @@ static int bcm3510_hab_send_request(struct bcm3510_state 
*st, u8 *buf, int len)
 
 static int bcm3510_do_hab_cmd(struct bcm3510_state *st, u8 cmd, u8 msgid, u8 
*obuf, u8 olen, u8 *ibuf, u8 ilen)
 {
-       u8 ob[olen+2],ib[ilen+2];
+       u8 ob[128], ib[128];
        int ret = 0;
 
+       if (ilen + 2 > sizeof(ib)) {
+               deb_hab("do_hab_cmd: ilen=%d is too big!\n", ilen);
+               return -EREMOTEIO;
+       }
+
+       if (olen + 2 > sizeof(ob)) {
+               deb_hab("do_hab_cmd: olen=%d is too big!\n", olen);
+               return -EREMOTEIO;
+       }
+
        ob[0] = cmd;
        ob[1] = msgid;
        memcpy(&ob[2],obuf,olen);
diff --git a/drivers/media/dvb-frontends/itd1000.c 
b/drivers/media/dvb-frontends/itd1000.c
index c1c3400b2173..1a8e9f83a002 100644
--- a/drivers/media/dvb-frontends/itd1000.c
+++ b/drivers/media/dvb-frontends/itd1000.c
@@ -52,10 +52,18 @@ MODULE_PARM_DESC(debug, "Turn on/off debugging 
(default:off).");
 /* don't write more than one byte with flexcop behind */
 static int itd1000_write_regs(struct itd1000_state *state, u8 reg, u8 v[], u8 
len)
 {
-       u8 buf[1+len];
+       u8 buf[80];
        struct i2c_msg msg = {
                .addr = state->cfg->i2c_address, .flags = 0, .buf = buf, .len = 
len+1
        };
+
+       if (1 + len > sizeof(buf)) {
+               printk(KERN_WARNING
+                      "itd1000: i2c wr reg=%04x: len=%d is too big!\n",
+                      reg, len);
+               return -EREMOTEIO;
+       }
+
        buf[0] = reg;
        memcpy(&buf[1], v, len);
 
diff --git a/drivers/media/dvb-frontends/mt312.c 
b/drivers/media/dvb-frontends/mt312.c
index ec388c1d6913..fee0e7938f48 100644
--- a/drivers/media/dvb-frontends/mt312.c
+++ b/drivers/media/dvb-frontends/mt312.c
@@ -96,9 +96,15 @@ static int mt312_write(struct mt312_state *state, const enum 
mt312_reg_addr reg,
                       const u8 *src, const size_t count)
 {
        int ret;
-       u8 buf[count + 1];
+       u8 buf[80];
        struct i2c_msg msg;
 
+       if (1 + count > sizeof(buf)) {
+               printk(KERN_WARNING
+                      "mt312: write: len=%zd is too big!\n", count);
+               return -EREMOTEIO;
+       }
+
        if (debug) {
                int i;
                dprintk("W(%d):", reg & 0x7f);
diff --git a/drivers/media/dvb-frontends/nxt200x.c 
b/drivers/media/dvb-frontends/nxt200x.c
index 8e288940a61f..335b35ce60c8 100644
--- a/drivers/media/dvb-frontends/nxt200x.c
+++ b/drivers/media/dvb-frontends/nxt200x.c
@@ -95,10 +95,16 @@ static int i2c_readbytes(struct nxt200x_state *state, u8 
addr, u8 *buf, u8 len)
 static int nxt200x_writebytes (struct nxt200x_state* state, u8 reg,
                               const u8 *buf, u8 len)
 {
-       u8 buf2 [len+1];
+       u8 buf2[80];
        int err;
        struct i2c_msg msg = { .addr = state->config->demod_address, .flags = 
0, .buf = buf2, .len = len + 1 };
 
+       if (1 + len > sizeof(buf2)) {
+               pr_warn("%s: i2c wr reg=%04x: len=%d is too big!\n",
+                        __func__, reg, len);
+               return -EREMOTEIO;
+       }
+
        buf2[0] = reg;
        memcpy(&buf2[1], buf, len);
 
diff --git a/drivers/media/dvb-frontends/stb6100.c 
b/drivers/media/dvb-frontends/stb6100.c
index 45f9523f968f..5623af5fcdd4 100644
--- a/drivers/media/dvb-frontends/stb6100.c
+++ b/drivers/media/dvb-frontends/stb6100.c
@@ -183,7 +183,7 @@ static int stb6100_read_reg(struct stb6100_state *state, u8 
reg)
 static int stb6100_write_reg_range(struct stb6100_state *state, u8 buf[], int 
start, int len)
 {
        int rc;
-       u8 cmdbuf[len + 1];
+       u8 cmdbuf[80];
        struct i2c_msg msg = {
                .addr   = state->config->tuner_address,
                .flags  = 0,
@@ -191,6 +191,13 @@ static int stb6100_write_reg_range(struct stb6100_state 
*state, u8 buf[], int st
                .len    = len + 1
        };
 
+       if (1 + len > sizeof(buf)) {
+               printk(KERN_WARNING
+                      "%s: i2c wr: len=%d is too big!\n",
+                      KBUILD_MODNAME, len);
+               return -EREMOTEIO;
+       }
+
        if (unlikely(start < 1 || start + len > STB6100_NUMREGS)) {
                dprintk(verbose, FE_ERROR, 1, "Invalid register range %d:%d",
                        start, len);
diff --git a/drivers/media/dvb-frontends/stv6110.c 
b/drivers/media/dvb-frontends/stv6110.c
index 20b5fa92c53e..4bb3f9a1cf2a 100644
--- a/drivers/media/dvb-frontends/stv6110.c
+++ b/drivers/media/dvb-frontends/stv6110.c
@@ -68,7 +68,7 @@ static int stv6110_write_regs(struct dvb_frontend *fe, u8 
buf[],
 {
        struct stv6110_priv *priv = fe->tuner_priv;
        int rc;
-       u8 cmdbuf[len + 1];
+       u8 cmdbuf[80];
        struct i2c_msg msg = {
                .addr   = priv->i2c_address,
                .flags  = 0,
@@ -78,6 +78,13 @@ static int stv6110_write_regs(struct dvb_frontend *fe, u8 
buf[],
 
        dprintk("%s\n", __func__);
 
+       if (1 + len > sizeof(cmdbuf)) {
+               printk(KERN_WARNING
+                      "%s: i2c wr: len=%d is too big!\n",
+                      KBUILD_MODNAME, len);
+               return -EREMOTEIO;
+       }
+
        if (start + len > 8)
                return -EINVAL;
 
diff --git a/drivers/media/dvb-frontends/stv6110x.c 
b/drivers/media/dvb-frontends/stv6110x.c
index f36cab12bdc7..41f1d34f64ac 100644
--- a/drivers/media/dvb-frontends/stv6110x.c
+++ b/drivers/media/dvb-frontends/stv6110x.c
@@ -61,7 +61,7 @@ static int stv6110x_write_regs(struct stv6110x_state 
*stv6110x, int start, u8 da
 {
        int ret;
        const struct stv6110x_config *config = stv6110x->config;
-       u8 buf[len + 1];
+       u8 buf[80];
        struct i2c_msg msg = {
                .addr = config->addr,
                .flags = 0,
@@ -69,6 +69,13 @@ static int stv6110x_write_regs(struct stv6110x_state 
*stv6110x, int start, u8 da
                .len = len + 1
        };
 
+       if (1 + len > sizeof(buf)) {
+               printk(KERN_WARNING
+                      "%s: i2c wr: len=%d is too big!\n",
+                      KBUILD_MODNAME, len);
+               return -EREMOTEIO;
+       }
+
        if (start + len > 8)
                return -EINVAL;
 
diff --git a/drivers/media/dvb-frontends/tda18271c2dd.c 
b/drivers/media/dvb-frontends/tda18271c2dd.c
index d281f77d5c28..d3aa82cd4eb7 100644
--- a/drivers/media/dvb-frontends/tda18271c2dd.c
+++ b/drivers/media/dvb-frontends/tda18271c2dd.c
@@ -139,11 +139,18 @@ static int i2c_write(struct i2c_adapter *adap, u8 adr, u8 
*data, int len)
 static int WriteRegs(struct tda_state *state,
                     u8 SubAddr, u8 *Regs, u16 nRegs)
 {
-       u8 data[nRegs+1];
+       u8 data[80];
+
+       if (1 + nRegs > sizeof(data)) {
+               printk(KERN_WARNING
+                      "%s: i2c wr: len=%d is too big!\n",
+                      KBUILD_MODNAME, nRegs);
+               return -EREMOTEIO;
+       }
 
        data[0] = SubAddr;
        memcpy(data + 1, Regs, nRegs);
-       return i2c_write(state->i2c, state->adr, data, nRegs+1);
+       return i2c_write(state->i2c, state->adr, data, nRegs + 1);
 }
 
 static int WriteReg(struct tda_state *state, u8 SubAddr, u8 Reg)
diff --git a/drivers/media/dvb-frontends/zl10039.c 
b/drivers/media/dvb-frontends/zl10039.c
index eff9c5fde50a..1e2d99b47bc3 100644
--- a/drivers/media/dvb-frontends/zl10039.c
+++ b/drivers/media/dvb-frontends/zl10039.c
@@ -98,7 +98,7 @@ static int zl10039_write(struct zl10039_state *state,
                        const enum zl10039_reg_addr reg, const u8 *src,
                        const size_t count)
 {
-       u8 buf[count + 1];
+       u8 buf[80];
        struct i2c_msg msg = {
                .addr = state->i2c_addr,
                .flags = 0,
@@ -106,6 +106,13 @@ static int zl10039_write(struct zl10039_state *state,
                .len = count + 1,
        };
 
+       if (1 + count > sizeof(buf)) {
+               printk(KERN_WARNING
+                      "%s: i2c wr reg=%04x: len=%zd is too big!\n",
+                      KBUILD_MODNAME, reg, count);
+               return -EREMOTEIO;
+       }
+
        dprintk("%s\n", __func__);
        /* Write register address and data in one go */
        buf[0] = reg;
-- 
1.8.3.1

--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to