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 --- fs/char_dev.c | 13 ++++++++++++- fs/proc/proc_misc.c | 2 +- 2 files changed, 13 insertions(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/char_dev.c b/fs/char_dev.c index c1e3537909fc..e82aac9cc2f5 100644 --- a/fs/char_dev.c +++ b/fs/char_dev.c @@ -56,10 +56,21 @@ int get_chrdev_list(char *page) down(&chrdevs_lock); for (i = 0; i < ARRAY_SIZE(chrdevs) ; i++) { - for (cd = chrdevs[i]; cd; cd = cd->next) + for (cd = chrdevs[i]; cd; cd = cd->next) { + /* + * if the current name, plus the 5 extra characters + * in the device line for this entry + * would run us off the page, we're done + */ + if ((len+strlen(cd->name) + 5) >= PAGE_SIZE) + goto page_full; + + len += sprintf(page+len, "%3d %s\n", cd->major, cd->name); + } } +page_full: up(&chrdevs_lock); return len; diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c index 63a9fbf1ac51..94b570ad037d 100644 --- a/fs/proc/proc_misc.c +++ b/fs/proc/proc_misc.c @@ -451,7 +451,7 @@ static int devices_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data) { int len = get_chrdev_list(page); - len += get_blkdev_list(page+len); + len += get_blkdev_list(page+len, len); return proc_calc_metrics(page, start, off, count, eof, len); } -- cgit v1.2.3