[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: Reinette Chatre <reinette.chatre@linux.intel.com> Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com> Cc: Paul Jackson <pj@sgi.com> Cc: Joe Korty <joe.korty@ccur.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -46,7 +46,8 @@
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* bitmap_remap(dst, src, old, new, nbits) *dst = map(old, new)(src)
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* bitmap_bitremap(oldbit, old, new, nbits) newbit = map(old, new)(oldbit)
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* bitmap_scnprintf(buf, len, src, nbits) Print bitmap src to buf
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* bitmap_parse(ubuf, ulen, dst, nbits) Parse bitmap dst from user buf
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* bitmap_parse(buf, buflen, dst, nbits) Parse bitmap dst from kernel buf
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* bitmap_parse_user(ubuf, ulen, dst, nbits) Parse bitmap dst from user buf
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* bitmap_scnlistprintf(buf, len, src, nbits) Print bitmap src as list to buf
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* bitmap_parselist(buf, dst, nbits) Parse bitmap dst from list
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* bitmap_find_free_region(bitmap, bits, order) Find and allocate bit region
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@ -106,7 +107,9 @@ extern int __bitmap_weight(const unsigned long *bitmap, int bits);
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extern int bitmap_scnprintf(char *buf, unsigned int len,
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const unsigned long *src, int nbits);
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extern int bitmap_parse(const char __user *ubuf, unsigned int ulen,
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extern int __bitmap_parse(const char *buf, unsigned int buflen, int is_user,
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unsigned long *dst, int nbits);
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extern int bitmap_parse_user(const char __user *ubuf, unsigned int ulen,
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unsigned long *dst, int nbits);
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extern int bitmap_scnlistprintf(char *buf, unsigned int len,
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const unsigned long *src, int nbits);
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@ -270,6 +273,12 @@ static inline void bitmap_shift_left(unsigned long *dst,
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__bitmap_shift_left(dst, src, n, nbits);
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}
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static inline int bitmap_parse(const char *buf, unsigned int buflen,
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unsigned long *maskp, int nmaskbits)
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{
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return __bitmap_parse(buf, buflen, 0, maskp, nmaskbits);
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}
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#endif /* __ASSEMBLY__ */
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#endif /* __LINUX_BITMAP_H */
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@ -8,8 +8,8 @@
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* See detailed comments in the file linux/bitmap.h describing the
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* data type on which these cpumasks are based.
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*
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* For details of cpumask_scnprintf() and cpumask_parse(),
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* see bitmap_scnprintf() and bitmap_parse() in lib/bitmap.c.
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* For details of cpumask_scnprintf() and cpumask_parse_user(),
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* see bitmap_scnprintf() and bitmap_parse_user() in lib/bitmap.c.
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* For details of cpulist_scnprintf() and cpulist_parse(), see
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* bitmap_scnlistprintf() and bitmap_parselist(), also in bitmap.c.
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* For details of cpu_remap(), see bitmap_bitremap in lib/bitmap.c
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@ -49,7 +49,7 @@
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* unsigned long *cpus_addr(mask) Array of unsigned long's in mask
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*
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* int cpumask_scnprintf(buf, len, mask) Format cpumask for printing
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* int cpumask_parse(ubuf, ulen, mask) Parse ascii string as cpumask
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* int cpumask_parse_user(ubuf, ulen, mask) Parse ascii string as cpumask
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* int cpulist_scnprintf(buf, len, mask) Format cpumask as list for printing
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* int cpulist_parse(buf, map) Parse ascii string as cpulist
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* int cpu_remap(oldbit, old, new) newbit = map(old, new)(oldbit)
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@ -273,12 +273,12 @@ static inline int __cpumask_scnprintf(char *buf, int len,
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return bitmap_scnprintf(buf, len, srcp->bits, nbits);
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}
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#define cpumask_parse(ubuf, ulen, dst) \
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__cpumask_parse((ubuf), (ulen), &(dst), NR_CPUS)
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static inline int __cpumask_parse(const char __user *buf, int len,
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#define cpumask_parse_user(ubuf, ulen, dst) \
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__cpumask_parse_user((ubuf), (ulen), &(dst), NR_CPUS)
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static inline int __cpumask_parse_user(const char __user *buf, int len,
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cpumask_t *dstp, int nbits)
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{
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return bitmap_parse(buf, len, dstp->bits, nbits);
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return bitmap_parse_user(buf, len, dstp->bits, nbits);
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}
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#define cpulist_scnprintf(buf, len, src) \
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@ -8,8 +8,8 @@
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* See detailed comments in the file linux/bitmap.h describing the
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* data type on which these nodemasks are based.
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*
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* For details of nodemask_scnprintf() and nodemask_parse(),
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* see bitmap_scnprintf() and bitmap_parse() in lib/bitmap.c.
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* For details of nodemask_scnprintf() and nodemask_parse_user(),
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* see bitmap_scnprintf() and bitmap_parse_user() in lib/bitmap.c.
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* For details of nodelist_scnprintf() and nodelist_parse(), see
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* bitmap_scnlistprintf() and bitmap_parselist(), also in bitmap.c.
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* For details of node_remap(), see bitmap_bitremap in lib/bitmap.c.
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@ -51,7 +51,7 @@
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* unsigned long *nodes_addr(mask) Array of unsigned long's in mask
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*
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* int nodemask_scnprintf(buf, len, mask) Format nodemask for printing
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* int nodemask_parse(ubuf, ulen, mask) Parse ascii string as nodemask
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* int nodemask_parse_user(ubuf, ulen, mask) Parse ascii string as nodemask
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* int nodelist_scnprintf(buf, len, mask) Format nodemask as list for printing
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* int nodelist_parse(buf, map) Parse ascii string as nodelist
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* int node_remap(oldbit, old, new) newbit = map(old, new)(oldbit)
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@ -288,12 +288,12 @@ static inline int __nodemask_scnprintf(char *buf, int len,
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return bitmap_scnprintf(buf, len, srcp->bits, nbits);
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}
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#define nodemask_parse(ubuf, ulen, dst) \
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__nodemask_parse((ubuf), (ulen), &(dst), MAX_NUMNODES)
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static inline int __nodemask_parse(const char __user *buf, int len,
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#define nodemask_parse_user(ubuf, ulen, dst) \
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__nodemask_parse_user((ubuf), (ulen), &(dst), MAX_NUMNODES)
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static inline int __nodemask_parse_user(const char __user *buf, int len,
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nodemask_t *dstp, int nbits)
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{
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return bitmap_parse(buf, len, dstp->bits, nbits);
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return bitmap_parse_user(buf, len, dstp->bits, nbits);
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}
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#define nodelist_scnprintf(buf, len, src) \
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@ -57,7 +57,7 @@ static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
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if (!irq_desc[irq].chip->set_affinity || no_irq_affinity)
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return -EIO;
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err = cpumask_parse(buffer, count, new_value);
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err = cpumask_parse_user(buffer, count, new_value);
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if (err)
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return err;
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@ -399,7 +399,7 @@ static int prof_cpu_mask_write_proc (struct file *file, const char __user *buffe
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unsigned long full_count = count, err;
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cpumask_t new_value;
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err = cpumask_parse(buffer, count, new_value);
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err = cpumask_parse_user(buffer, count, new_value);
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if (err)
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return err;
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54
lib/bitmap.c
54
lib/bitmap.c
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@ -316,10 +316,11 @@ int bitmap_scnprintf(char *buf, unsigned int buflen,
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EXPORT_SYMBOL(bitmap_scnprintf);
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/**
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* bitmap_parse - convert an ASCII hex string into a bitmap.
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* @ubuf: pointer to buffer in user space containing string.
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* @ubuflen: buffer size in bytes. If string is smaller than this
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* __bitmap_parse - convert an ASCII hex string into a bitmap.
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* @buf: pointer to buffer containing string.
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* @buflen: buffer size in bytes. If string is smaller than this
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* then it must be terminated with a \0.
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* @is_user: location of buffer, 0 indicates kernel space
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* @maskp: pointer to bitmap array that will contain result.
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* @nmaskbits: size of bitmap, in bits.
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*
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@ -330,11 +331,13 @@ EXPORT_SYMBOL(bitmap_scnprintf);
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* characters and for grouping errors such as "1,,5", ",44", "," and "".
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* Leading and trailing whitespace accepted, but not embedded whitespace.
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*/
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int bitmap_parse(const char __user *ubuf, unsigned int ubuflen,
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unsigned long *maskp, int nmaskbits)
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int __bitmap_parse(const char *buf, unsigned int buflen,
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int is_user, unsigned long *maskp,
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int nmaskbits)
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{
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int c, old_c, totaldigits, ndigits, nchunks, nbits;
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u32 chunk;
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const char __user *ubuf = buf;
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bitmap_zero(maskp, nmaskbits);
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chunk = ndigits = 0;
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/* Get the next chunk of the bitmap */
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while (ubuflen) {
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while (buflen) {
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old_c = c;
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if (get_user(c, ubuf++))
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return -EFAULT;
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ubuflen--;
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if (is_user) {
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if (__get_user(c, ubuf++))
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return -EFAULT;
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}
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else
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c = *buf++;
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buflen--;
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if (isspace(c))
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continue;
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nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
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if (nbits > nmaskbits)
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return -EOVERFLOW;
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} while (ubuflen && c == ',');
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} while (buflen && c == ',');
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return 0;
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}
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EXPORT_SYMBOL(bitmap_parse);
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EXPORT_SYMBOL(__bitmap_parse);
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/**
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* bitmap_parse_user()
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*
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* @ubuf: pointer to user buffer containing string.
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* @ulen: buffer size in bytes. If string is smaller than this
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* then it must be terminated with a \0.
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* @maskp: pointer to bitmap array that will contain result.
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* @nmaskbits: size of bitmap, in bits.
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*
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* Wrapper for __bitmap_parse(), providing it with user buffer.
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*
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* We cannot have this as an inline function in bitmap.h because it needs
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* linux/uaccess.h to get the access_ok() declaration and this causes
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* cyclic dependencies.
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*/
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int bitmap_parse_user(const char __user *ubuf,
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unsigned int ulen, unsigned long *maskp,
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int nmaskbits)
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{
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if (!access_ok(VERIFY_READ, ubuf, ulen))
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return -EFAULT;
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return __bitmap_parse((const char *)ubuf, ulen, 1, maskp, nmaskbits);
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}
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EXPORT_SYMBOL(bitmap_parse_user);
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/*
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* bscnl_emit(buf, buflen, rbot, rtop, bp)
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