diff options
Diffstat (limited to 'fs/pipe.c')
| -rw-r--r-- | fs/pipe.c | 54 |
1 files changed, 42 insertions, 12 deletions
diff --git a/fs/pipe.c b/fs/pipe.c index f98fae3e36b..69c4c7c13ea 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -26,9 +26,14 @@ /* * The max size that a non-root user is allowed to grow the pipe. Can - * be set by root in /proc/sys/fs/pipe-max-pages + * be set by root in /proc/sys/fs/pipe-max-size */ -unsigned int pipe_max_pages = PIPE_DEF_BUFFERS * 16; +unsigned int pipe_max_size = 1048576; + +/* + * Minimum pipe size, as required by POSIX + */ +unsigned int pipe_min_size = PAGE_SIZE; /* * We use a start+len construction, which provides full use of the @@ -1156,6 +1161,35 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages) return nr_pages * PAGE_SIZE; } +/* + * Currently we rely on the pipe array holding a power-of-2 number + * of pages. + */ +static inline unsigned int round_pipe_size(unsigned int size) +{ + unsigned long nr_pages; + + nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; + return roundup_pow_of_two(nr_pages) << PAGE_SHIFT; +} + +/* + * This should work even if CONFIG_PROC_FS isn't set, as proc_dointvec_minmax + * will return an error. + */ +int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf, + size_t *lenp, loff_t *ppos) +{ + int ret; + + ret = proc_dointvec_minmax(table, write, buf, lenp, ppos); + if (ret < 0 || !write) + return ret; + + pipe_max_size = round_pipe_size(pipe_max_size); + return ret; +} + long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) { struct pipe_inode_info *pipe; @@ -1169,23 +1203,19 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) switch (cmd) { case F_SETPIPE_SZ: { - unsigned long nr_pages; + unsigned int size, nr_pages; - /* - * Currently the array must be a power-of-2 size, so adjust - * upwards if needed. - */ - nr_pages = (arg + PAGE_SIZE - 1) >> PAGE_SHIFT; - nr_pages = roundup_pow_of_two(nr_pages); + size = round_pipe_size(arg); + nr_pages = size >> PAGE_SHIFT; - if (!capable(CAP_SYS_RESOURCE) && nr_pages > pipe_max_pages) { + if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size) { ret = -EPERM; goto out; - } else if (nr_pages < 1) { + } else if (nr_pages < PAGE_SIZE) { ret = -EINVAL; goto out; } - ret = pipe_set_size(pipe, arg); + ret = pipe_set_size(pipe, nr_pages); break; } case F_GETPIPE_SZ: |