[PATCH 1/5] kernel: replace sizeof(task->comm) with TASK_COMM_LEN

From: Yafang Shao
Date: Wed Sep 29 2021 - 07:51:26 EST

We can use TASK_COMM_LEN directly instread of sizeof(task->comm).

This patch also replace strlcpy with strscpy, to fix the warning by
checkpatch -
WARNING: Prefer strscpy over strlcpy - see: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@xxxxxxxxxxxxxx/

Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
---
arch/ia64/kernel/mca.c | 6 +++---
drivers/block/drbd/drbd_main.c | 2 +-
drivers/hwtracing/stm/core.c | 2 +-
drivers/tty/tty_audit.c | 2 +-
fs/exec.c | 2 +-
kernel/audit.c | 4 ++--
kernel/auditsc.c | 4 ++--
kernel/capability.c | 4 ++--
kernel/futex.c | 2 +-
kernel/sys.c | 2 +-
kernel/trace/blktrace.c | 2 +-
security/lsm_audit.c | 4 ++--
security/selinux/selinuxfs.c | 2 +-
security/yama/yama_lsm.c | 2 +-
sound/core/oss/pcm_oss.c | 2 +-
15 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/arch/ia64/kernel/mca.c b/arch/ia64/kernel/mca.c
index e628a88607bb..4ee86e91ff5e 100644
--- a/arch/ia64/kernel/mca.c
+++ b/arch/ia64/kernel/mca.c
@@ -875,7 +875,7 @@ copy_reg(const u64 *fr, u64 fnat, unsigned long *tr, unsigned long *tnat)
static void
ia64_mca_modify_comm(const struct task_struct *previous_current)
{
- char *p, comm[sizeof(current->comm)];
+ char *p, comm[TASK_COMM_LEN];
if (previous_current->pid)
snprintf(comm, sizeof(comm), "%s %d",
current->comm, previous_current->pid);
@@ -889,7 +889,7 @@ ia64_mca_modify_comm(const struct task_struct *previous_current)
current->comm, l, previous_current->comm,
task_thread_info(previous_current)->cpu);
}
- memcpy(current->comm, comm, sizeof(current->comm));
+ memcpy(current->comm, comm, TASK_COMM_LEN);
}

static void
@@ -1794,7 +1794,7 @@ format_mca_init_stack(void *mca_data, unsigned long offset,
p->parent = p->real_parent = p->group_leader = p;
INIT_LIST_HEAD(&p->children);
INIT_LIST_HEAD(&p->sibling);
- strncpy(p->comm, type, sizeof(p->comm)-1);
+ strncpy(p->comm, type, TASK_COMM_LEN-1);
}

/* Caller prevents this from being called after init */
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 55234a558e98..a7cf062e76ab 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -306,7 +306,7 @@ static int drbd_thread_setup(void *arg)
unsigned long flags;
int retval;

- snprintf(current->comm, sizeof(current->comm), "drbd_%c_%s",
+ snprintf(current->comm, TASK_COMM_LEN, "drbd_%c_%s",
thi->name[0],
resource->name);

diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c
index 2712e699ba08..8ec0a34a9ba6 100644
--- a/drivers/hwtracing/stm/core.c
+++ b/drivers/hwtracing/stm/core.c
@@ -631,7 +631,7 @@ static ssize_t stm_char_write(struct file *file, const char __user *buf,
* point, try to use the task name and "default" policy entries.
*/
if (!stmf->output.nr_chans) {
- char comm[sizeof(current->comm)];
+ char comm[TASK_COMM_LEN];
char *ids[] = { comm, "default", NULL };

get_task_comm(comm, current);
diff --git a/drivers/tty/tty_audit.c b/drivers/tty/tty_audit.c
index ca7afd7b2716..b98b1aef5f6f 100644
--- a/drivers/tty/tty_audit.c
+++ b/drivers/tty/tty_audit.c
@@ -69,7 +69,7 @@ static void tty_audit_log(const char *description, dev_t dev,

ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_TTY);
if (ab) {
- char name[sizeof(current->comm)];
+ char name[TASK_COMM_LEN];

audit_log_format(ab, "%s pid=%u uid=%u auid=%u ses=%u major=%d"
" minor=%d comm=", description, pid, uid,
diff --git a/fs/exec.c b/fs/exec.c
index a098c133d8d7..021c9dc727bc 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1224,7 +1224,7 @@ void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec)
{
task_lock(tsk);
trace_task_rename(tsk, buf);
- strlcpy(tsk->comm, buf, sizeof(tsk->comm));
+ strscpy(tsk->comm, buf, TASK_COMM_LEN);
task_unlock(tsk);
perf_event_comm(tsk, exec);
}
diff --git a/kernel/audit.c b/kernel/audit.c
index 121d37e700a6..1fbd036e77be 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1549,7 +1549,7 @@ static void audit_log_multicast(int group, const char *op, int err)
{
const struct cred *cred;
struct tty_struct *tty;
- char comm[sizeof(current->comm)];
+ char comm[TASK_COMM_LEN];
struct audit_buffer *ab;

if (!audit_enabled)
@@ -2192,7 +2192,7 @@ void audit_put_tty(struct tty_struct *tty)
void audit_log_task_info(struct audit_buffer *ab)
{
const struct cred *cred;
- char comm[sizeof(current->comm)];
+ char comm[TASK_COMM_LEN];
struct tty_struct *tty;

if (!ab)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 8dd73a64f921..295376d7d926 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2595,7 +2595,7 @@ void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries,
enum audit_nfcfgop op, gfp_t gfp)
{
struct audit_buffer *ab;
- char comm[sizeof(current->comm)];
+ char comm[TASK_COMM_LEN];

ab = audit_log_start(audit_context(), gfp, AUDIT_NETFILTER_CFG);
if (!ab)
@@ -2616,7 +2616,7 @@ static void audit_log_task(struct audit_buffer *ab)
kuid_t auid, uid;
kgid_t gid;
unsigned int sessionid;
- char comm[sizeof(current->comm)];
+ char comm[TASK_COMM_LEN];

auid = audit_get_loginuid(current);
sessionid = audit_get_sessionid(current);
diff --git a/kernel/capability.c b/kernel/capability.c
index 46a361dde042..4033ee837f63 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -45,7 +45,7 @@ __setup("no_file_caps", file_caps_disable);

static void warn_legacy_capability_use(void)
{
- char name[sizeof(current->comm)];
+ char name[TASK_COMM_LEN];

pr_info_once("warning: `%s' uses 32-bit capabilities (legacy support in use)\n",
get_task_comm(name, current));
@@ -69,7 +69,7 @@ static void warn_legacy_capability_use(void)

static void warn_deprecated_v2(void)
{
- char name[sizeof(current->comm)];
+ char name[TASK_COMM_LEN];

pr_info_once("warning: `%s' uses deprecated v2 capabilities in a way that may be insecure\n",
get_task_comm(name, current));
diff --git a/kernel/futex.c b/kernel/futex.c
index c15ad276fd15..6cd08156611e 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1703,7 +1703,7 @@ static int futex_atomic_op_inuser(unsigned int encoded_op, u32 __user *uaddr)

if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) {
if (oparg < 0 || oparg > 31) {
- char comm[sizeof(current->comm)];
+ char comm[TASK_COMM_LEN];
/*
* kill this print and return -EINVAL when userspace
* is sane again
diff --git a/kernel/sys.c b/kernel/sys.c
index 8fdac0d90504..bea1120c5579 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2265,7 +2265,7 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
unsigned long, arg4, unsigned long, arg5)
{
struct task_struct *me = current;
- unsigned char comm[sizeof(me->comm)];
+ unsigned char comm[TASK_COMM_LEN];
long error;

error = security_task_prctl(option, arg2, arg3, arg4, arg5);
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index c221e4c3f625..009f77ebda5a 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -124,7 +124,7 @@ static void trace_note_tsk(struct task_struct *tsk)
spin_lock_irqsave(&running_trace_lock, flags);
list_for_each_entry(bt, &running_trace_list, running_list) {
trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
- sizeof(tsk->comm), 0);
+ TASK_COMM_LEN, 0);
}
spin_unlock_irqrestore(&running_trace_lock, flags);
}
diff --git a/security/lsm_audit.c b/security/lsm_audit.c
index 5a5016ef43b0..eec54cb48845 100644
--- a/security/lsm_audit.c
+++ b/security/lsm_audit.c
@@ -208,7 +208,7 @@ static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
static void dump_common_audit_data(struct audit_buffer *ab,
struct common_audit_data *a)
{
- char comm[sizeof(current->comm)];
+ char comm[TASK_COMM_LEN];

/*
* To keep stack sizes in check force programers to notice if they
@@ -310,7 +310,7 @@ static void dump_common_audit_data(struct audit_buffer *ab,
if (tsk) {
pid_t pid = task_tgid_nr(tsk);
if (pid) {
- char comm[sizeof(tsk->comm)];
+ char comm[TASK_COMM_LEN];
audit_log_format(ab, " opid=%d ocomm=", pid);
audit_log_untrustedstring(ab,
memcpy(comm, tsk->comm, sizeof(comm)));
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index e4cd7cb856f3..e529db76502d 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -752,7 +752,7 @@ static ssize_t sel_write_checkreqprot(struct file *file, const char __user *buf,
goto out;

if (new_value) {
- char comm[sizeof(current->comm)];
+ char comm[TASK_COMM_LEN];

memcpy(comm, current->comm, sizeof(comm));
pr_warn_once("SELinux: %s (%d) set checkreqprot to 1. This is deprecated and will be rejected in a future kernel release.\n",
diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c
index 06e226166aab..178d7a138e98 100644
--- a/security/yama/yama_lsm.c
+++ b/security/yama/yama_lsm.c
@@ -75,7 +75,7 @@ static void report_access(const char *access, struct task_struct *target,
struct task_struct *agent)
{
struct access_report_info *info;
- char agent_comm[sizeof(agent->comm)];
+ char agent_comm[TASK_COMM_LEN];

assert_spin_locked(&target->alloc_lock); /* for target->comm */

diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index 82a818734a5f..d541530236e1 100644
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -2460,7 +2460,7 @@ static int snd_task_name(struct task_struct *task, char *name, size_t size)

if (snd_BUG_ON(!task || !name || size < 2))
return -EINVAL;
- for (idx = 0; idx < sizeof(task->comm) && idx + 1 < size; idx++)
+ for (idx = 0; idx < TASK_COMM_LEN && idx + 1 < size; idx++)
name[idx] = task->comm[idx];
name[idx] = '\0';
return 0;
--
2.17.1