[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 <nhorman@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/char_dev.c b/fs/char_dev.c
index c1e3537..e82aac9 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -56,10 +56,21 @@
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;