[PATCH] Fix check warnings in PPP code

Paul Mackerras (paulus@samba.org)
Sat, 7 Jun 2003 21:50:30 +1000


Linus,

This patch removes the warnings that the check program came up with in
the PPP code: ppp_async.c, ppp_deflate.c and ppp_generic.c. This
involved adding __user and converting K&R-style function definitions
to ANSI-style. I also took the time to add some extra comments to
ppp_deflate.c explaining in more detail what each function does and
what its arguments are.

Please apply.

Thanks,
Paul.

diff -urN linux-2.5/drivers/net/ppp_async.c pmac-2.5/drivers/net/ppp_async.c
--- linux-2.5/drivers/net/ppp_async.c 2003-04-25 09:17:22.000000000 +1000
+++ pmac-2.5/drivers/net/ppp_async.c 2003-06-07 17:45:00.000000000 +1000
@@ -427,12 +427,12 @@
break;

case PPPIOCGXASYNCMAP:
- if (copy_to_user((void *) arg, ap->xaccm, sizeof(ap->xaccm)))
+ if (copy_to_user((void __user *) arg, ap->xaccm, sizeof(ap->xaccm)))
break;
err = 0;
break;
case PPPIOCSXASYNCMAP:
- if (copy_from_user(accm, (void *) arg, sizeof(accm)))
+ if (copy_from_user(accm, (void __user *) arg, sizeof(accm)))
break;
accm[2] &= ~0x40000000U; /* can't escape 0x5e */
accm[3] |= 0x60000000U; /* must escape 0x7d, 0x7e */
diff -urN linux-2.5/drivers/net/ppp_deflate.c pmac-2.5/drivers/net/ppp_deflate.c
--- linux-2.5/drivers/net/ppp_deflate.c 2003-05-07 14:25:43.000000000 +1000
+++ pmac-2.5/drivers/net/ppp_deflate.c 2003-06-07 19:36:29.000000000 +1000
@@ -57,29 +57,31 @@

#define DEFLATE_OVHD 2 /* Deflate overhead/packet */

-static void *z_comp_alloc __P((unsigned char *options, int opt_len));
-static void *z_decomp_alloc __P((unsigned char *options, int opt_len));
-static void z_comp_free __P((void *state));
-static void z_decomp_free __P((void *state));
-static int z_comp_init __P((void *state, unsigned char *options,
+static void *z_comp_alloc(unsigned char *options, int opt_len);
+static void *z_decomp_alloc(unsigned char *options, int opt_len);
+static void z_comp_free(void *state);
+static void z_decomp_free(void *state);
+static int z_comp_init(void *state, unsigned char *options,
int opt_len,
- int unit, int hdrlen, int debug));
-static int z_decomp_init __P((void *state, unsigned char *options,
+ int unit, int hdrlen, int debug);
+static int z_decomp_init(void *state, unsigned char *options,
int opt_len,
- int unit, int hdrlen, int mru, int debug));
-static int z_compress __P((void *state, unsigned char *rptr,
+ int unit, int hdrlen, int mru, int debug);
+static int z_compress(void *state, unsigned char *rptr,
unsigned char *obuf,
- int isize, int osize));
-static void z_incomp __P((void *state, unsigned char *ibuf, int icnt));
-static int z_decompress __P((void *state, unsigned char *ibuf,
- int isize, unsigned char *obuf, int osize));
-static void z_comp_reset __P((void *state));
-static void z_decomp_reset __P((void *state));
-static void z_comp_stats __P((void *state, struct compstat *stats));
-
-static void
-z_comp_free(arg)
- void *arg;
+ int isize, int osize);
+static void z_incomp(void *state, unsigned char *ibuf, int icnt);
+static int z_decompress(void *state, unsigned char *ibuf,
+ int isize, unsigned char *obuf, int osize);
+static void z_comp_reset(void *state);
+static void z_decomp_reset(void *state);
+static void z_comp_stats(void *state, struct compstat *stats);
+
+/**
+ * z_comp_free - free the memory used by a compressor
+ * @arg: pointer to the private state for the compressor.
+ */
+static void z_comp_free(void *arg)
{
struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;

@@ -91,13 +93,21 @@
}
}

-/*
- * Allocate space for a compressor.
+/**
+ * z_comp_alloc - allocate space for a compressor.
+ * @options: pointer to CCP option data
+ * @opt_len: length of the CCP option at @options.
+ *
+ * The @options pointer points to the a buffer containing the
+ * CCP option data for the compression being negotiated. It is
+ * formatted according to RFC1979, and describes the window
+ * size that the peer is requesting that we use in compressing
+ * data to be sent to it.
+ *
+ * Returns the pointer to the private state for the compressor,
+ * or NULL if we could not allocate enough memory.
*/
-static void *
-z_comp_alloc(options, opt_len)
- unsigned char *options;
- int opt_len;
+static void *z_comp_alloc(unsigned char *options, int opt_len)
{
struct ppp_deflate_state *state;
int w_size;
@@ -135,11 +145,23 @@
return NULL;
}

-static int
-z_comp_init(arg, options, opt_len, unit, hdrlen, debug)
- void *arg;
- unsigned char *options;
- int opt_len, unit, hdrlen, debug;
+/**
+ * z_comp_init - initialize a previously-allocated compressor.
+ * @arg: pointer to the private state for the compressor
+ * @options: pointer to the CCP option data describing the
+ * compression that was negotiated with the peer
+ * @opt_len: length of the CCP option data at @options
+ * @unit: PPP unit number for diagnostic messages
+ * @hdrlen: ignored (present for backwards compatibility)
+ * @debug: debug flag; if non-zero, debug messages are printed.
+ *
+ * The CCP options described by @options must match the options
+ * specified when the compressor was allocated. The compressor
+ * history is reset. Returns 0 for failure (CCP options don't
+ * match) or 1 for success.
+ */
+static int z_comp_init(void *arg, unsigned char *options, int opt_len,
+ int unit, int hdrlen, int debug)
{
struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;

@@ -160,9 +182,14 @@
return 1;
}

-static void
-z_comp_reset(arg)
- void *arg;
+/**
+ * z_comp_reset - reset a previously-allocated compressor.
+ * @arg: pointer to private state for the compressor.
+ *
+ * This clears the history for the compressor and makes it
+ * ready to start emitting a new compressed stream.
+ */
+static void z_comp_reset(void *arg)
{
struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;

@@ -170,12 +197,19 @@
zlib_deflateReset(&state->strm);
}

-int
-z_compress(arg, rptr, obuf, isize, osize)
- void *arg;
- unsigned char *rptr; /* uncompressed packet (in) */
- unsigned char *obuf; /* compressed packet (out) */
- int isize, osize;
+/**
+ * z_compress - compress a PPP packet with Deflate compression.
+ * @arg: pointer to private state for the compressor
+ * @rptr: uncompressed packet (input)
+ * @obuf: compressed packet (output)
+ * @isize: size of uncompressed packet
+ * @osize: space available at @obuf
+ *
+ * Returns the length of the compressed packet, or 0 if the
+ * packet is incompressible.
+ */
+int z_compress(void *arg, unsigned char *rptr, unsigned char *obuf,
+ int isize, int osize)
{
struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
int r, proto, off, olen, oavail;
@@ -251,19 +285,24 @@
return olen;
}

-static void
-z_comp_stats(arg, stats)
- void *arg;
- struct compstat *stats;
+/**
+ * z_comp_stats - return compression statistics for a compressor
+ * or decompressor.
+ * @arg: pointer to private space for the (de)compressor
+ * @stats: pointer to a struct compstat to receive the result.
+ */
+static void z_comp_stats(void *arg, struct compstat *stats)
{
struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;

*stats = state->stats;
}

-static void
-z_decomp_free(arg)
- void *arg;
+/**
+ * z_decomp_free - Free the memory used by a decompressor.
+ * @arg: pointer to private space for the decompressor.
+ */
+static void z_decomp_free(void *arg)
{
struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;

@@ -275,13 +314,21 @@
}
}

-/*
- * Allocate space for a decompressor.
+/**
+ * z_decomp_alloc - allocate space for a decompressor.
+ * @options: pointer to CCP option data
+ * @opt_len: length of the CCP option at @options.
+ *
+ * The @options pointer points to the a buffer containing the
+ * CCP option data for the compression being negotiated. It is
+ * formatted according to RFC1979, and describes the window
+ * size that we are requesting the peer to use in compressing
+ * data to be sent to us.
+ *
+ * Returns the pointer to the private state for the decompressor,
+ * or NULL if we could not allocate enough memory.
*/
-static void *
-z_decomp_alloc(options, opt_len)
- unsigned char *options;
- int opt_len;
+static void *z_decomp_alloc(unsigned char *options, int opt_len)
{
struct ppp_deflate_state *state;
int w_size;
@@ -317,11 +364,24 @@
return NULL;
}

-static int
-z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug)
- void *arg;
- unsigned char *options;
- int opt_len, unit, hdrlen, mru, debug;
+/**
+ * z_decomp_init - initialize a previously-allocated decompressor.
+ * @arg: pointer to the private state for the decompressor
+ * @options: pointer to the CCP option data describing the
+ * compression that was negotiated with the peer
+ * @opt_len: length of the CCP option data at @options
+ * @unit: PPP unit number for diagnostic messages
+ * @hdrlen: ignored (present for backwards compatibility)
+ * @mru: maximum length of decompressed packets
+ * @debug: debug flag; if non-zero, debug messages are printed.
+ *
+ * The CCP options described by @options must match the options
+ * specified when the decompressor was allocated. The decompressor
+ * history is reset. Returns 0 for failure (CCP options don't
+ * match) or 1 for success.
+ */
+static int z_decomp_init(void *arg, unsigned char *options, int opt_len,
+ int unit, int hdrlen, int mru, int debug)
{
struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;

@@ -343,9 +403,14 @@
return 1;
}

-static void
-z_decomp_reset(arg)
- void *arg;
+/**
+ * z_decomp_reset - reset a previously-allocated decompressor.
+ * @arg: pointer to private state for the decompressor.
+ *
+ * This clears the history for the decompressor and makes it
+ * ready to receive a new compressed stream.
+ */
+static void z_decomp_reset(void *arg)
{
struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;

@@ -353,8 +418,13 @@
zlib_inflateReset(&state->strm);
}

-/*
- * Decompress a Deflate-compressed packet.
+/**
+ * z_decompress - decompress a Deflate-compressed packet.
+ * @arg: pointer to private state for the decompressor
+ * @ibuf: pointer to input (compressed) packet data
+ * @isize: length of input packet
+ * @obuf: pointer to space for output (decompressed) packet
+ * @osize: amount of space available at @obuf
*
* Because of patent problems, we return DECOMP_ERROR for errors
* found by inspecting the input data and for system problems, but
@@ -369,13 +439,8 @@
* bug, so we return DECOMP_FATALERROR for them in order to turn off
* compression, even though they are detected by inspecting the input.
*/
-int
-z_decompress(arg, ibuf, isize, obuf, osize)
- void *arg;
- unsigned char *ibuf;
- int isize;
- unsigned char *obuf;
- int osize;
+int z_decompress(void *arg, unsigned char *ibuf, int isize,
+ unsigned char *obuf, int osize)
{
struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
int olen, seq, r;
@@ -474,14 +539,13 @@
return olen;
}

-/*
- * Incompressible data has arrived - add it to the history.
+/**
+ * z_incomp - add incompressible input data to the history.
+ * @arg: pointer to private state for the decompressor
+ * @ibuf: pointer to input packet data
+ * @icnt: length of input data.
*/
-static void
-z_incomp(arg, ibuf, icnt)
- void *arg;
- unsigned char *ibuf;
- int icnt;
+static void z_incomp(void *arg, unsigned char *ibuf, int icnt)
{
struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
int proto, r;
diff -urN linux-2.5/drivers/net/ppp_generic.c pmac-2.5/drivers/net/ppp_generic.c
--- linux-2.5/drivers/net/ppp_generic.c 2003-06-02 18:02:30.000000000 +1000
+++ pmac-2.5/drivers/net/ppp_generic.c 2003-06-07 17:47:39.000000000 +1000
@@ -387,7 +387,7 @@
return 0;
}

-static ssize_t ppp_read(struct file *file, char *buf,
+static ssize_t ppp_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct ppp_file *pf = file->private_data;
@@ -436,7 +436,7 @@
return ret;
}

-static ssize_t ppp_write(struct file *file, const char *buf,
+static ssize_t ppp_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct ppp_file *pf = file->private_data;
@@ -617,7 +617,7 @@
case PPPIOCGIDLE:
idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
- if (copy_to_user((void *) arg, &idle, sizeof(idle)))
+ if (copy_to_user((void __user *) arg, &idle, sizeof(idle)))
break;
err = 0;
break;
@@ -646,7 +646,7 @@

case PPPIOCGNPMODE:
case PPPIOCSNPMODE:
- if (copy_from_user(&npi, (void *) arg, sizeof(npi)))
+ if (copy_from_user(&npi, (void __user *) arg, sizeof(npi)))
break;
err = proto_to_npindex(npi.protocol);
if (err < 0)
@@ -655,7 +655,7 @@
if (cmd == PPPIOCGNPMODE) {
err = -EFAULT;
npi.mode = ppp->npmode[i];
- if (copy_to_user((void *) arg, &npi, sizeof(npi)))
+ if (copy_to_user((void __user *) arg, &npi, sizeof(npi)))
break;
} else {
ppp->npmode[i] = npi.mode;
@@ -673,24 +673,22 @@
struct sock_filter *code = NULL;
int len;

- if (copy_from_user(&uprog, (void *) arg, sizeof(uprog)))
+ if (copy_from_user(&uprog, (void __user *) arg, sizeof(uprog)))
+ break;
+ err = -ENOMEM;
+ len = uprog.len * sizeof(struct sock_filter);
+ code = kmalloc(len, GFP_KERNEL);
+ if (code == 0)
+ break;
+ err = -EFAULT;
+ if (copy_from_user(code, (void __user *) uprog.filter, len)) {
+ kfree(code);
+ break;
+ }
+ err = sk_chk_filter(code, uprog.len);
+ if (err) {
+ kfree(code);
break;
- if (uprog.len > 0 && uprog.len < 65536) {
- err = -ENOMEM;
- len = uprog.len * sizeof(struct sock_filter);
- code = kmalloc(len, GFP_KERNEL);
- if (code == 0)
- break;
- err = -EFAULT;
- if (copy_from_user(code, uprog.filter, len)) {
- kfree(code);
- break;
- }
- err = sk_chk_filter(code, uprog.len);
- if (err) {
- kfree(code);
- break;
- }
}
filtp = (cmd == PPPIOCSPASS)? &ppp->pass_filter: &ppp->active_filter;
ppp_lock(ppp);
@@ -879,7 +877,7 @@
{
struct ppp *ppp = dev->priv;
int err = -EFAULT;
- void *addr = (void *) ifr->ifr_ifru.ifru_data;
+ void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
struct ppp_stats stats;
struct ppp_comp_stats cstats;
char *vers;
@@ -1952,9 +1950,9 @@
unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];

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