Re: [PATCH 1/2] string: Add stracpy and stracpy_pad mechanisms

Joe Perches
2019-07-23T04:42:56Z

On Mon, 2019-07-22 at 21:35 -0700, Andrew Morton wrote:
> On Mon, 22 Jul 2019 17:38:15 -0700 Joe Perches <joe@perches.com> wrote:
>
> > Several uses of strlcpy and strscpy have had defects because the
> > last argument of each function is misused or typoed.
> >
> > Add macro mechanisms to avoid this defect.
> >
> > stracpy (copy a string to a string array) must have a string
> > array as the first argument (to) and uses sizeof(to) as the
> > size.
> >
> > These mechanisms verify that the to argument is an array of
> > char or other compatible types like u8 or unsigned char.
> >
> > A BUILD_BUG is emitted when the type of to is not compatible.
> >
>
> It would be nice to include some conversions. To demonstrate the need,
> to test the code, etc.

How about all the kernel/ ?
---
kernel/acct.c | 2 +-
kernel/cgroup/cgroup-v1.c | 3 +--
kernel/debug/gdbstub.c | 4 ++--
kernel/debug/kdb/kdb_support.c | 2 +-
kernel/events/core.c | 4 ++--
kernel/module.c | 2 +-
kernel/printk/printk.c | 2 +-
kernel/time/clocksource.c | 2 +-
8 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/kernel/acct.c b/kernel/acct.c
index 81f9831a7859..5ad29248b654 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -425,7 +425,7 @@ static void fill_ac(acct_t *ac)
memset(ac, 0, sizeof(acct_t));

ac->ac_version = ACCT_VERSION | ACCT_BYTEORDER;
- strlcpy(ac->ac_comm, current->comm, sizeof(ac->ac_comm));
+ stracpy(ac->ac_comm, current->comm);

/* calculate run_time in nsec*/
run_time = ktime_get_ns();
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 88006be40ea3..dd4f041e4179 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -571,8 +571,7 @@ static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of,
if (!cgrp)
return -ENODEV;
spin_lock(&release_agent_path_lock);
- strlcpy(cgrp->root->release_agent_path, strstrip(buf),
- sizeof(cgrp->root->release_agent_path));
+ stracpy(cgrp->root->release_agent_path, strstrip(buf));
spin_unlock(&release_agent_path_lock);
cgroup_kn_unlock(of->kn);
return nbytes;
diff --git a/kernel/debug/gdbstub.c b/kernel/debug/gdbstub.c
index 4b280fc7dd67..a263f27f51ad 100644
--- a/kernel/debug/gdbstub.c
+++ b/kernel/debug/gdbstub.c
@@ -1095,10 +1095,10 @@ int gdbstub_state(struct kgdb_state *ks, char *cmd)
return error;
case 's':
case 'c':
- strscpy(remcom_in_buffer, cmd, sizeof(remcom_in_buffer));
+ stracpy(remcom_in_buffer, cmd);
return 0;
case '$':
- strscpy(remcom_in_buffer, cmd, sizeof(remcom_in_buffer));
+ stracpy(remcom_in_buffer, cmd);
gdbstub_use_prev_in_buf = strlen(remcom_in_buffer);
gdbstub_prev_in_buf_pos = 0;
return 0;
diff --git a/kernel/debug/kdb/kdb_support.c b/kernel/debug/kdb/kdb_support.c
index b8e6306e7e13..b49b6c3976c7 100644
--- a/kernel/debug/kdb/kdb_support.c
+++ b/kernel/debug/kdb/kdb_support.c
@@ -192,7 +192,7 @@ int kallsyms_symbol_complete(char *prefix_name, int max_len)

while ((name = kdb_walk_kallsyms(&pos))) {
if (strncmp(name, prefix_name, prefix_len) == 0) {
- strscpy(ks_namebuf, name, sizeof(ks_namebuf));
+ stracpy(ks_namebuf, name);
/* Work out the longest name that matches the prefix */
if (++number == 1) {
prev_len = min_t(int, max_len-1,
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 026a14541a38..25bd8c777270 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7049,7 +7049,7 @@ static void perf_event_comm_event(struct perf_comm_event *comm_event)
unsigned int size;

memset(comm, 0, sizeof(comm));
- strlcpy(comm, comm_event->task->comm, sizeof(comm));
+ stracpy(comm, comm_event->task->comm);
size = ALIGN(strlen(comm)+1, sizeof(u64));

comm_event->comm = comm;
@@ -7394,7 +7394,7 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
}

cpy_name:
- strlcpy(tmp, name, sizeof(tmp));
+ stracpy(tmp, name);
name = tmp;
got_name:
/*
diff --git a/kernel/module.c b/kernel/module.c
index 5933395af9a0..39384b0c90b8 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1021,7 +1021,7 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
async_synchronize_full();

/* Store the name of the last unloaded module for diagnostic purposes */
- strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));
+ stracpy(last_unloaded_module, mod->name);

free_module(mod);
return 0;
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 424abf802f02..029633052be4 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2127,7 +2127,7 @@ static int __add_preferred_console(char *name, int idx, char *options,
return -E2BIG;
if (!brl_options)
preferred_console = i;
- strlcpy(c->name, name, sizeof(c->name));
+ stracpy(c->name, name);
c->options = options;
braille_set_options(c, brl_options);

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index fff5f64981c6..f0c833d89ace 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -1203,7 +1203,7 @@ static int __init boot_override_clocksource(char* str)
{
mutex_lock(&clocksource_mutex);
if (str)
- strlcpy(override_name, str, sizeof(override_name));
+ stracpy(override_name, str);
mutex_unlock(&clocksource_mutex);
return 1;
}