From f05e53a7fbb28c951c0c8cf3963fa8019ae1d4d3 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Sat, 21 Jan 2012 10:03:13 -0800 Subject: [PATCH] sysctl: Create local copies of directory names used in paths Creating local copies of directory names is a good idea for two reasons. - The dynamic names used by callers must be copied into new strings by the callers today to ensure the strings do not change between register and unregister of the sysctl table. - Sysctl directories have a potentially different lifetime than the time between register and unregister of any particular sysctl table. Signed-off-by: Eric W. Biederman --- fs/proc/proc_sysctl.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 86d32a318e2c..bcf60fb8dce5 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -943,10 +943,12 @@ struct ctl_table_header *__register_sysctl_paths( struct ctl_table *new, **prevp; unsigned int n, npath; struct ctl_table_set *set; + size_t path_bytes = 0; + char *new_name; /* Count the path components */ for (npath = 0; path[npath].procname; ++npath) - ; + path_bytes += strlen(path[npath].procname) + 1; /* * For each path component, allocate a 2-element ctl_table array. @@ -956,24 +958,27 @@ struct ctl_table_header *__register_sysctl_paths( * We allocate everything in one go so that we don't have to * worry about freeing additional memory in unregister_sysctl_table. */ - header = kzalloc(sizeof(struct ctl_table_header) + + header = kzalloc(sizeof(struct ctl_table_header) + path_bytes + (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL); if (!header) return NULL; new = (struct ctl_table *) (header + 1); + new_name = (char *)(new + (2 * npath)); /* Now connect the dots */ prevp = &header->ctl_table; for (n = 0; n < npath; ++n, ++path) { /* Copy the procname */ - new->procname = path->procname; + strcpy(new_name, path->procname); + new->procname = new_name; new->mode = 0555; *prevp = new; prevp = &new->child; new += 2; + new_name += strlen(new_name) + 1; } *prevp = table; header->ctl_table_arg = table; -- 2.39.2