From ac20427ef6aa63da663bdc88b71d16f7394f5e23 Mon Sep 17 00:00:00 2001 From: Neil Horman Date: Thu, 23 Jun 2005 00:09:11 -0700 Subject: [PATCH] add check to /proc/devices read routines Patch to add check to get_chrdev_list and get_blkdev_list to prevent reads of /proc/devices from spilling over the provided page if more than 4096 bytes of string data are generated from all the registered character and block devices in a system Signed-off-by: Neil Horman Cc: Christoph Hellwig Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/block/genhd.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/block/genhd.c b/drivers/block/genhd.c index 43805e4d31e..47fd3659a06 100644 --- a/drivers/block/genhd.c +++ b/drivers/block/genhd.c @@ -40,7 +40,7 @@ static inline int major_to_index(int major) #ifdef CONFIG_PROC_FS /* get block device names in somewhat random order */ -int get_blkdev_list(char *p) +int get_blkdev_list(char *p, int used) { struct blk_major_name *n; int i, len; @@ -49,10 +49,18 @@ int get_blkdev_list(char *p) down(&block_subsys_sem); for (i = 0; i < ARRAY_SIZE(major_names); i++) { - for (n = major_names[i]; n; n = n->next) + for (n = major_names[i]; n; n = n->next) { + /* + * If the curent string plus the 5 extra characters + * in the line would run us off the page, then we're done + */ + if ((len + used + strlen(n->name) + 5) >= PAGE_SIZE) + goto page_full; len += sprintf(p+len, "%3d %s\n", n->major, n->name); + } } +page_full: up(&block_subsys_sem); return len; -- cgit v1.2.3