From 01a3ee2b203e511e20f98b85a9172fd32c53e87c Mon Sep 17 00:00:00 2001 From: Reinette Chatre Date: Wed, 11 Oct 2006 01:21:55 -0700 Subject: [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 Signed-off-by: Inaky Perez-Gonzalez Cc: Paul Jackson Cc: Joe Korty Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/bitmap.h | 13 ++++++++++-- include/linux/cpumask.h | 14 ++++++------- include/linux/nodemask.h | 14 ++++++------- kernel/irq/proc.c | 2 +- kernel/profile.c | 2 +- lib/bitmap.c | 54 ++++++++++++++++++++++++++++++++++++++---------- 6 files changed, 70 insertions(+), 29 deletions(-) diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index dcc5de7cc487..64b4641904fe 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -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 */ diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index b268a3c0c376..d0e8c8b0e34d 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.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) \ diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h index 5dce5c21822c..b1063e9cdb1b 100644 --- a/include/linux/nodemask.h +++ b/include/linux/nodemask.h @@ -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) \ diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 607c7809ad01..9a352667007c 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -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; diff --git a/kernel/profile.c b/kernel/profile.c index 857300a2afec..f940b462eec9 100644 --- a/kernel/profile.c +++ b/kernel/profile.c @@ -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; diff --git a/lib/bitmap.c b/lib/bitmap.c index d71e38c54ea5..037fa9aa2ed7 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -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) -- cgit v1.2.2