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compat_ioctl: move PPPIOCSCOMPRESS to ppp_generic
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Rather than using a compat_alloc_user_space() buffer, moving
this next to the native handler allows sharing most of
the code, leaving only the user copy portion distinct.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: netdev@vger.kernel.org
Cc: linux-ppp@vger.kernel.org
Cc: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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Al Viro authored and Arnd Bergmann committed Oct 23, 2019
1 parent 3e859ad commit 5b6c02d
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Showing 2 changed files with 38 additions and 47 deletions.
53 changes: 38 additions & 15 deletions drivers/net/ppp/ppp_generic.c
Original file line number Diff line number Diff line change
Expand Up @@ -270,7 +270,7 @@ static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
#endif /* CONFIG_PPP_MULTILINK */
static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data);
static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
static void ppp_ccp_closed(struct ppp *ppp);
static struct compressor *find_compressor(int type);
Expand Down Expand Up @@ -708,9 +708,14 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
break;

case PPPIOCSCOMPRESS:
err = ppp_set_compress(ppp, arg);
{
struct ppp_option_data data;
if (copy_from_user(&data, argp, sizeof(data)))
err = -EFAULT;
else
err = ppp_set_compress(ppp, &data);
break;

}
case PPPIOCGUNIT:
if (put_user(ppp->file.index, p))
break;
Expand Down Expand Up @@ -827,6 +832,13 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
}

#ifdef CONFIG_COMPAT
struct ppp_option_data32 {
compat_uptr_t ptr;
u32 length;
compat_int_t transmit;
};
#define PPPIOCSCOMPRESS32 _IOW('t', 77, struct ppp_option_data32)

static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct ppp_file *pf;
Expand Down Expand Up @@ -863,6 +875,21 @@ static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long
break;
}
#endif /* CONFIG_PPP_FILTER */
case PPPIOCSCOMPRESS32:
{
struct ppp_option_data32 data32;
if (copy_from_user(&data32, argp, sizeof(data32))) {
err = -EFAULT;
} else {
struct ppp_option_data data = {
.ptr = compat_ptr(data32.ptr),
.length = data32.length,
.transmit = data32.transmit
};
err = ppp_set_compress(ppp, &data);
}
break;
}
}
}
mutex_unlock(&ppp_mutex);
Expand Down Expand Up @@ -2783,24 +2810,20 @@ ppp_output_wakeup(struct ppp_channel *chan)

/* Process the PPPIOCSCOMPRESS ioctl. */
static int
ppp_set_compress(struct ppp *ppp, unsigned long arg)
ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
{
int err;
int err = -EFAULT;
struct compressor *cp, *ocomp;
struct ppp_option_data data;
void *state, *ostate;
unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];

err = -EFAULT;
if (copy_from_user(&data, (void __user *) arg, sizeof(data)))
goto out;
if (data.length > CCP_MAX_OPTION_LENGTH)
if (data->length > CCP_MAX_OPTION_LENGTH)
goto out;
if (copy_from_user(ccp_option, (void __user *) data.ptr, data.length))
if (copy_from_user(ccp_option, data->ptr, data->length))
goto out;

err = -EINVAL;
if (data.length < 2 || ccp_option[1] < 2 || ccp_option[1] > data.length)
if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
goto out;

cp = try_then_request_module(
Expand All @@ -2810,8 +2833,8 @@ ppp_set_compress(struct ppp *ppp, unsigned long arg)
goto out;

err = -ENOBUFS;
if (data.transmit) {
state = cp->comp_alloc(ccp_option, data.length);
if (data->transmit) {
state = cp->comp_alloc(ccp_option, data->length);
if (state) {
ppp_xmit_lock(ppp);
ppp->xstate &= ~SC_COMP_RUN;
Expand All @@ -2829,7 +2852,7 @@ ppp_set_compress(struct ppp *ppp, unsigned long arg)
module_put(cp->owner);

} else {
state = cp->decomp_alloc(ccp_option, data.length);
state = cp->decomp_alloc(ccp_option, data->length);
if (state) {
ppp_recv_lock(ppp);
ppp->rstate &= ~SC_DECOMP_RUN;
Expand Down
32 changes: 0 additions & 32 deletions fs/compat_ioctl.c
Original file line number Diff line number Diff line change
Expand Up @@ -99,13 +99,6 @@ static int sg_grt_trans(struct file *file,
}
#endif /* CONFIG_BLOCK */

struct ppp_option_data32 {
compat_caddr_t ptr;
u32 length;
compat_int_t transmit;
};
#define PPPIOCSCOMPRESS32 _IOW('t', 77, struct ppp_option_data32)

struct ppp_idle32 {
compat_time_t xmit_idle;
compat_time_t recv_idle;
Expand Down Expand Up @@ -133,29 +126,6 @@ static int ppp_gidle(struct file *file, unsigned int cmd,
return err;
}

static int ppp_scompress(struct file *file, unsigned int cmd,
struct ppp_option_data32 __user *odata32)
{
struct ppp_option_data __user *odata;
__u32 data;
void __user *datap;

odata = compat_alloc_user_space(sizeof(*odata));

if (get_user(data, &odata32->ptr))
return -EFAULT;

datap = compat_ptr(data);
if (put_user(datap, &odata->ptr))
return -EFAULT;

if (copy_in_user(&odata->length, &odata32->length,
sizeof(__u32) + sizeof(int)))
return -EFAULT;

return do_ioctl(file, PPPIOCSCOMPRESS, (unsigned long) odata);
}

/*
* simple reversible transform to make our table more evenly
* distributed after sorting.
Expand Down Expand Up @@ -249,8 +219,6 @@ static long do_ioctl_trans(unsigned int cmd,
switch (cmd) {
case PPPIOCGIDLE32:
return ppp_gidle(file, cmd, argp);
case PPPIOCSCOMPRESS32:
return ppp_scompress(file, cmd, argp);
#ifdef CONFIG_BLOCK
case SG_GET_REQUEST_TABLE:
return sg_grt_trans(file, cmd, argp);
Expand Down

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