[PATCH v7 4/4] boot/param: add pointer to next argument to unknown parameter callback

Michal Suchanek
2017-08-17T20:15:25Z

The fadump parameter processing re-does the logic of next_arg quote
stripping to determine where the argument ends. Pass pointer to the
next argument instead to make this more robust.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/kernel/fadump.c | 13 +++++--------
arch/powerpc/mm/hugetlbpage.c | 4 ++--
include/linux/moduleparam.h | 2 +-
init/main.c | 12 ++++++------
kernel/module.c | 4 ++--
kernel/params.c | 19 +++++++++++--------
lib/dynamic_debug.c | 2 +-
7 files changed, 28 insertions(+), 28 deletions(-)

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index d7da4ce9f7ae..6ef96711ee9a 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -474,13 +474,14 @@ struct param_info {
};

static void __init fadump_update_params(struct param_info *param_info,
- char *param, char *val)
+ char *param, char *val, char *next)
{
ptrdiff_t param_offset = param - param_info->tmp_cmdline;
size_t vallen = val ? strlen(val) : 0;
char *tgt = param_info->cmdline + param_offset +
FADUMP_EXTRA_ARGS_LEN - param_info->shortening;
- int shortening = 0;
+ int shortening = ((next - 1) - (param))
+ - (FADUMP_EXTRA_ARGS_LEN + 1 + vallen);

if (!val)
return;
@@ -488,10 +489,6 @@ static void __init fadump_update_params(struct param_info *param_info,
/* remove '=' */
*tgt++ = ' ';

- /* next_arg removes one leading and one trailing '"' */
- if ((*tgt == '"') && (*(tgt + vallen + shortening) == '"'))
- shortening += 2;
-
/* remove one leading and one trailing quote if both are present */
if ((val[0] == '"') && (val[vallen - 1] == '"')) {
shortening += 2;
@@ -517,7 +514,7 @@ static void __init fadump_update_params(struct param_info *param_info,
* to enforce the parameters passed through it
*/
static int __init fadump_rework_cmdline_params(char *param, char *val,
- const char *unused, void *arg)
+ char *next, const char *unused, void *arg)
{
struct param_info *param_info = (struct param_info *)arg;

@@ -525,7 +522,7 @@ static int __init fadump_rework_cmdline_params(char *param, char *val,
strlen(FADUMP_EXTRA_ARGS_PARAM) - 1))
return 0;

- fadump_update_params(param_info, param, val);
+ fadump_update_params(param_info, param, val, next);

return 0;
}
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index e1bf5ca397fe..3a4cce552906 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -268,8 +268,8 @@ int alloc_bootmem_huge_page(struct hstate *hstate)

unsigned long gpage_npages[MMU_PAGE_COUNT];

-static int __init do_gpage_early_setup(char *param, char *val,
- const char *unused, void *arg)
+static int __init do_gpage_early_setup(char *param, char *val, char *unused1,
+ const char *unused2, void *arg)
{
static phys_addr_t size;
unsigned long npages;
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index 1ee7b30dafec..fec05a186c08 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -326,7 +326,7 @@ extern char *parse_args(const char *name,
s16 level_min,
s16 level_max,
void *arg,
- int (*unknown)(char *param, char *val,
+ int (*unknown)(char *param, char *val, char *next,
const char *doing, void *arg));

/* Called by module remove. */
diff --git a/init/main.c b/init/main.c
index 052481fbe363..920c3564b2f0 100644
--- a/init/main.c
+++ b/init/main.c
@@ -239,7 +239,7 @@ static int __init loglevel(char *str)
early_param("loglevel", loglevel);

/* Change NUL term back to "=", to make "param" the whole string. */
-static int __init repair_env_string(char *param, char *val,
+static int __init repair_env_string(char *param, char *val, char *unused2,
const char *unused, void *arg)
{
if (val) {
@@ -257,7 +257,7 @@ static int __init repair_env_string(char *param, char *val,
}

/* Anything after -- gets handed straight to init. */
-static int __init set_init_arg(char *param, char *val,
+static int __init set_init_arg(char *param, char *val, char *unused2,
const char *unused, void *arg)
{
unsigned int i;
@@ -265,7 +265,7 @@ static int __init set_init_arg(char *param, char *val,
if (panic_later)
return 0;

- repair_env_string(param, val, unused, NULL);
+ repair_env_string(param, val, unused2, unused, NULL);

for (i = 0; argv_init[i]; i++) {
if (i == MAX_INIT_ARGS) {
@@ -282,10 +282,10 @@ static int __init set_init_arg(char *param, char *val,
* Unknown boot options get handed to init, unless they look like
* unused parameters (modprobe will find them in /proc/cmdline).
*/
-static int __init unknown_bootoption(char *param, char *val,
+static int __init unknown_bootoption(char *param, char *val, char *unused2,
const char *unused, void *arg)
{
- repair_env_string(param, val, unused, NULL);
+ repair_env_string(param, val, unused2, unused, NULL);

/* Handle obsolete-style parameters */
if (obsolete_checksetup(param))
@@ -437,7 +437,7 @@ static noinline void __ref rest_init(void)
}

/* Check for early params. */
-static int __init do_early_param(char *param, char *val,
+static int __init do_early_param(char *param, char *val, char *unused2,
const char *unused, void *arg)
{
const struct obs_kernel_param *p;
diff --git a/kernel/module.c b/kernel/module.c
index 40f983cbea81..5e241ba95a91 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3609,8 +3609,8 @@ static int prepare_coming_module(struct module *mod)
return 0;
}

-static int unknown_module_param_cb(char *param, char *val, const char *modname,
- void *arg)
+static int unknown_module_param_cb(char *param, char *val, char *next,
+ const char *modname, void *arg)
{
struct module *mod = arg;
int ret;
diff --git a/kernel/params.c b/kernel/params.c
index 60b2d8101355..9f568fbf5287 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -119,13 +119,14 @@ static void param_check_unsafe(const struct kernel_param *kp)

static int parse_one(char *param,
char *val,
+ char *next,
const char *doing,
const struct kernel_param *params,
unsigned num_params,
s16 min_level,
s16 max_level,
void *arg,
- int (*handle_unknown)(char *param, char *val,
+ int (*handle_unknown)(char *param, char *val, char *next,
const char *doing, void *arg))
{
unsigned int i;
@@ -153,7 +154,7 @@ static int parse_one(char *param,

if (handle_unknown) {
pr_debug("doing %s: %s='%s'\n", doing, param, val);
- return handle_unknown(param, val, doing, arg);
+ return handle_unknown(param, val, next, doing, arg);
}

pr_debug("Unknown argument '%s'\n", param);
@@ -168,10 +169,10 @@ char *parse_args(const char *doing,
s16 min_level,
s16 max_level,
void *arg,
- int (*unknown)(char *param, char *val,
+ int (*unknown)(char *param, char *val, char *next,
const char *doing, void *arg))
{
- char *param, *val, *err = NULL;
+ char *param, *val, *next, *err = NULL;

/* Chew leading spaces */
args = skip_spaces(args);
@@ -179,16 +180,18 @@ char *parse_args(const char *doing,
if (*args)
pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);

- while (*args) {
+ next = next_arg(args, &param, &val);
+ do {
int ret;
int irq_was_disabled;

- args = next_arg(args, &param, &val);
+ args = next;
+ next = next_arg(args, &param, &val);
/* Stop at -- */
if (!val && strcmp(param, "--") == 0)
return err ?: args;
irq_was_disabled = irqs_disabled();
- ret = parse_one(param, val, doing, params, num,
+ ret = parse_one(param, val, next, doing, params, num,
min_level, max_level, arg, unknown);
if (irq_was_disabled && !irqs_disabled())
pr_warn("%s: option '%s' enabled irq's!\n",
@@ -211,7 +214,7 @@ char *parse_args(const char *doing,
}

err = ERR_PTR(ret);
- }
+ } while (*next);

return err;
}
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index da796e2dc4f5..bdedc1ca5bf6 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -888,7 +888,7 @@ static int ddebug_dyndbg_param_cb(char *param, char *val,
}

/* handle both dyndbg and $module.dyndbg params at boot */
-static int ddebug_dyndbg_boot_param_cb(char *param, char *val,
+static int ddebug_dyndbg_boot_param_cb(char *param, char *val, char *unused2,
const char *unused, void *arg)
{
vpr_info("%s=\"%s\"\n", param, val);
--
2.10.2