Commit 01a3ee2b authored by Reinette Chatre's avatar Reinette Chatre Committed by Linus Torvalds
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[PATCH] bitmap: parse input from kernel and user buffers



lib/bitmap.c:bitmap_parse() is a library function that received as input a
user buffer.  This seemed to have originated from the way the write_proc
function of the /proc filesystem operates.

This has been reworked to not use kmalloc and eliminates a lot of
get_user() overhead by performing one access_ok before using __get_user().

We need to test if we are in kernel or user space (is_user) and access the
buffer differently.  We cannot use __get_user() to access kernel addresses
in all cases, for example in architectures with separate address space for
kernel and user.

This function will be useful for other uses as well; for example, taking
input for /sysfs instead of /proc, so it was changed to accept kernel
buffers.  We have this use for the Linux UWB project, as part as the
upcoming bandwidth allocator code.

Only a few routines used this function and they were changed too.
Signed-off-by: default avatarReinette Chatre <reinette.chatre@linux.intel.com>
Signed-off-by: default avatarInaky Perez-Gonzalez <inaky@linux.intel.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Joe Korty <joe.korty@ccur.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 39484e53
......@@ -46,7 +46,8 @@
* bitmap_remap(dst, src, old, new, nbits) *dst = map(old, new)(src)
* bitmap_bitremap(oldbit, old, new, nbits) newbit = map(old, new)(oldbit)
* bitmap_scnprintf(buf, len, src, nbits) Print bitmap src to buf
* bitmap_parse(ubuf, ulen, dst, nbits) Parse bitmap dst from user buf
* bitmap_parse(buf, buflen, dst, nbits) Parse bitmap dst from kernel buf
* bitmap_parse_user(ubuf, ulen, dst, nbits) Parse bitmap dst from user buf
* bitmap_scnlistprintf(buf, len, src, nbits) Print bitmap src as list to buf
* bitmap_parselist(buf, dst, nbits) Parse bitmap dst from list
* bitmap_find_free_region(bitmap, bits, order) Find and allocate bit region
......@@ -106,7 +107,9 @@ extern int __bitmap_weight(const unsigned long *bitmap, int bits);
extern int bitmap_scnprintf(char *buf, unsigned int len,
const unsigned long *src, int nbits);
extern int bitmap_parse(const char __user *ubuf, unsigned int ulen,
extern int __bitmap_parse(const char *buf, unsigned int buflen, int is_user,
unsigned long *dst, int nbits);
extern int bitmap_parse_user(const char __user *ubuf, unsigned int ulen,
unsigned long *dst, int nbits);
extern int bitmap_scnlistprintf(char *buf, unsigned int len,
const unsigned long *src, int nbits);
......@@ -270,6 +273,12 @@ static inline void bitmap_shift_left(unsigned long *dst,
__bitmap_shift_left(dst, src, n, nbits);
}
static inline int bitmap_parse(const char *buf, unsigned int buflen,
unsigned long *maskp, int nmaskbits)
{
return __bitmap_parse(buf, buflen, 0, maskp, nmaskbits);
}
#endif /* __ASSEMBLY__ */
#endif /* __LINUX_BITMAP_H */
......@@ -8,8 +8,8 @@
* See detailed comments in the file linux/bitmap.h describing the
* data type on which these cpumasks are based.
*
* For details of cpumask_scnprintf() and cpumask_parse(),
* see bitmap_scnprintf() and bitmap_parse() in lib/bitmap.c.
* For details of cpumask_scnprintf() and cpumask_parse_user(),
* see bitmap_scnprintf() and bitmap_parse_user() in lib/bitmap.c.
* For details of cpulist_scnprintf() and cpulist_parse(), see
* bitmap_scnlistprintf() and bitmap_parselist(), also in bitmap.c.
* For details of cpu_remap(), see bitmap_bitremap in lib/bitmap.c
......@@ -49,7 +49,7 @@
* unsigned long *cpus_addr(mask) Array of unsigned long's in mask
*
* int cpumask_scnprintf(buf, len, mask) Format cpumask for printing
* int cpumask_parse(ubuf, ulen, mask) Parse ascii string as cpumask
* int cpumask_parse_user(ubuf, ulen, mask) Parse ascii string as cpumask
* int cpulist_scnprintf(buf, len, mask) Format cpumask as list for printing
* int cpulist_parse(buf, map) Parse ascii string as cpulist
* int cpu_remap(oldbit, old, new) newbit = map(old, new)(oldbit)
......@@ -273,12 +273,12 @@ static inline int __cpumask_scnprintf(char *buf, int len,
return bitmap_scnprintf(buf, len, srcp->bits, nbits);
}
#define cpumask_parse(ubuf, ulen, dst) \
__cpumask_parse((ubuf), (ulen), &(dst), NR_CPUS)
static inline int __cpumask_parse(const char __user *buf, int len,
#define cpumask_parse_user(ubuf, ulen, dst) \
__cpumask_parse_user((ubuf), (ulen), &(dst), NR_CPUS)
static inline int __cpumask_parse_user(const char __user *buf, int len,
cpumask_t *dstp, int nbits)
{
return bitmap_parse(buf, len, dstp->bits, nbits);
return bitmap_parse_user(buf, len, dstp->bits, nbits);
}
#define cpulist_scnprintf(buf, len, src) \
......
......@@ -8,8 +8,8 @@
* See detailed comments in the file linux/bitmap.h describing the
* data type on which these nodemasks are based.
*
* For details of nodemask_scnprintf() and nodemask_parse(),
* see bitmap_scnprintf() and bitmap_parse() in lib/bitmap.c.
* For details of nodemask_scnprintf() and nodemask_parse_user(),
* see bitmap_scnprintf() and bitmap_parse_user() in lib/bitmap.c.
* For details of nodelist_scnprintf() and nodelist_parse(), see
* bitmap_scnlistprintf() and bitmap_parselist(), also in bitmap.c.
* For details of node_remap(), see bitmap_bitremap in lib/bitmap.c.
......@@ -51,7 +51,7 @@
* unsigned long *nodes_addr(mask) Array of unsigned long's in mask
*
* int nodemask_scnprintf(buf, len, mask) Format nodemask for printing
* int nodemask_parse(ubuf, ulen, mask) Parse ascii string as nodemask
* int nodemask_parse_user(ubuf, ulen, mask) Parse ascii string as nodemask
* int nodelist_scnprintf(buf, len, mask) Format nodemask as list for printing
* int nodelist_parse(buf, map) Parse ascii string as nodelist
* int node_remap(oldbit, old, new) newbit = map(old, new)(oldbit)
......@@ -288,12 +288,12 @@ static inline int __nodemask_scnprintf(char *buf, int len,
return bitmap_scnprintf(buf, len, srcp->bits, nbits);
}
#define nodemask_parse(ubuf, ulen, dst) \
__nodemask_parse((ubuf), (ulen), &(dst), MAX_NUMNODES)
static inline int __nodemask_parse(const char __user *buf, int len,
#define nodemask_parse_user(ubuf, ulen, dst) \
__nodemask_parse_user((ubuf), (ulen), &(dst), MAX_NUMNODES)
static inline int __nodemask_parse_user(const char __user *buf, int len,
nodemask_t *dstp, int nbits)
{
return bitmap_parse(buf, len, dstp->bits, nbits);
return bitmap_parse_user(buf, len, dstp->bits, nbits);
}
#define nodelist_scnprintf(buf, len, src) \
......
......@@ -57,7 +57,7 @@ static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
if (!irq_desc[irq].chip->set_affinity || no_irq_affinity)
return -EIO;
err = cpumask_parse(buffer, count, new_value);
err = cpumask_parse_user(buffer, count, new_value);
if (err)
return err;
......
......@@ -399,7 +399,7 @@ static int prof_cpu_mask_write_proc (struct file *file, const char __user *buffe
unsigned long full_count = count, err;
cpumask_t new_value;
err = cpumask_parse(buffer, count, new_value);
err = cpumask_parse_user(buffer, count, new_value);
if (err)
return err;
......
......@@ -316,10 +316,11 @@ int bitmap_scnprintf(char *buf, unsigned int buflen,
EXPORT_SYMBOL(bitmap_scnprintf);
/**
* bitmap_parse - convert an ASCII hex string into a bitmap.
* @ubuf: pointer to buffer in user space containing string.
* @ubuflen: buffer size in bytes. If string is smaller than this
* __bitmap_parse - convert an ASCII hex string into a bitmap.
* @buf: pointer to buffer containing string.
* @buflen: buffer size in bytes. If string is smaller than this
* then it must be terminated with a \0.
* @is_user: location of buffer, 0 indicates kernel space
* @maskp: pointer to bitmap array that will contain result.
* @nmaskbits: size of bitmap, in bits.
*
......@@ -330,11 +331,13 @@ EXPORT_SYMBOL(bitmap_scnprintf);
* characters and for grouping errors such as "1,,5", ",44", "," and "".
* Leading and trailing whitespace accepted, but not embedded whitespace.
*/
int bitmap_parse(const char __user *ubuf, unsigned int ubuflen,
unsigned long *maskp, int nmaskbits)
int __bitmap_parse(const char *buf, unsigned int buflen,
int is_user, unsigned long *maskp,
int nmaskbits)
{
int c, old_c, totaldigits, ndigits, nchunks, nbits;
u32 chunk;
const char __user *ubuf = buf;
bitmap_zero(maskp, nmaskbits);
......@@ -343,11 +346,15 @@ int bitmap_parse(const char __user *ubuf, unsigned int ubuflen,
chunk = ndigits = 0;
/* Get the next chunk of the bitmap */
while (ubuflen) {
while (buflen) {
old_c = c;
if (get_user(c, ubuf++))
return -EFAULT;
ubuflen--;
if (is_user) {
if (__get_user(c, ubuf++))
return -EFAULT;
}
else
c = *buf++;
buflen--;
if (isspace(c))
continue;
......@@ -388,11 +395,36 @@ int bitmap_parse(const char __user *ubuf, unsigned int ubuflen,
nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
if (nbits > nmaskbits)
return -EOVERFLOW;
} while (ubuflen && c == ',');
} while (buflen && c == ',');
return 0;
}
EXPORT_SYMBOL(bitmap_parse);
EXPORT_SYMBOL(__bitmap_parse);
/**
* bitmap_parse_user()
*
* @ubuf: pointer to user buffer containing string.
* @ulen: buffer size in bytes. If string is smaller than this
* then it must be terminated with a \0.
* @maskp: pointer to bitmap array that will contain result.
* @nmaskbits: size of bitmap, in bits.
*
* Wrapper for __bitmap_parse(), providing it with user buffer.
*
* We cannot have this as an inline function in bitmap.h because it needs
* linux/uaccess.h to get the access_ok() declaration and this causes
* cyclic dependencies.
*/
int bitmap_parse_user(const char __user *ubuf,
unsigned int ulen, unsigned long *maskp,
int nmaskbits)
{
if (!access_ok(VERIFY_READ, ubuf, ulen))
return -EFAULT;
return __bitmap_parse((const char *)ubuf, ulen, 1, maskp, nmaskbits);
}
EXPORT_SYMBOL(bitmap_parse_user);
/*
* bscnl_emit(buf, buflen, rbot, rtop, bp)
......
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