From: Eric Biggers <[email protected]> Before validating the given value against pipe_min_size, do_proc_dopipe_max_size_conv() calls round_pipe_size(), which rounds the value up to pipe_min_size. Therefore, the second check against pipe_min_size is redundant. Remove it.
Acked-by: Kees Cook <[email protected]> Signed-off-by: Eric Biggers <[email protected]> --- fs/pipe.c | 10 +++------- include/linux/pipe_fs_i.h | 2 +- kernel/sysctl.c | 15 +-------------- 3 files changed, 5 insertions(+), 22 deletions(-) diff --git a/fs/pipe.c b/fs/pipe.c index 6d98566201ef..a75f5d2ca99c 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -35,11 +35,6 @@ */ unsigned int pipe_max_size = 1048576; -/* - * Minimum pipe size, as required by POSIX - */ -unsigned int pipe_min_size = PAGE_SIZE; - /* Maximum allocatable pages per user. Hard limit is unset by default, soft * matches default values. */ @@ -1024,8 +1019,9 @@ unsigned int round_pipe_size(unsigned int size) { unsigned long nr_pages; - if (size < pipe_min_size) - size = pipe_min_size; + /* Minimum pipe size, as required by POSIX */ + if (size < PAGE_SIZE) + size = PAGE_SIZE; nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; if (nr_pages == 0) diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h index 2dc5e9870fcd..7d9beda14584 100644 --- a/include/linux/pipe_fs_i.h +++ b/include/linux/pipe_fs_i.h @@ -167,7 +167,7 @@ void pipe_lock(struct pipe_inode_info *); void pipe_unlock(struct pipe_inode_info *); void pipe_double_lock(struct pipe_inode_info *, struct pipe_inode_info *); -extern unsigned int pipe_max_size, pipe_min_size; +extern unsigned int pipe_max_size; extern unsigned long pipe_user_pages_hard; extern unsigned long pipe_user_pages_soft; int pipe_proc_fn(struct ctl_table *, int, void __user *, size_t *, loff_t *); diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 557d46728577..a71ebb5c5182 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1820,7 +1820,6 @@ static struct ctl_table fs_table[] = { .maxlen = sizeof(pipe_max_size), .mode = 0644, .proc_handler = &pipe_proc_fn, - .extra1 = &pipe_min_size, }, { .procname = "pipe-user-pages-hard", @@ -2622,16 +2621,10 @@ int proc_douintvec_minmax(struct ctl_table *table, int write, do_proc_douintvec_minmax_conv, ¶m); } -struct do_proc_dopipe_max_size_conv_param { - unsigned int *min; -}; - static int do_proc_dopipe_max_size_conv(unsigned long *lvalp, unsigned int *valp, int write, void *data) { - struct do_proc_dopipe_max_size_conv_param *param = data; - if (write) { unsigned int val; @@ -2642,9 +2635,6 @@ static int do_proc_dopipe_max_size_conv(unsigned long *lvalp, if (val == 0) return -EINVAL; - if (param->min && *param->min > val) - return -ERANGE; - *valp = val; } else { unsigned int val = *valp; @@ -2657,11 +2647,8 @@ static int do_proc_dopipe_max_size_conv(unsigned long *lvalp, int proc_dopipe_max_size(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { - struct do_proc_dopipe_max_size_conv_param param = { - .min = (unsigned int *) table->extra1, - }; return do_proc_douintvec(table, write, buffer, lenp, ppos, - do_proc_dopipe_max_size_conv, ¶m); + do_proc_dopipe_max_size_conv, NULL); } static void validate_coredump_safety(void) -- 2.15.1
