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usb: core: fix quirks_param_set() writing to a const pointer

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[ Upstream commit b1b6bed3b5036509b449b5965285d5057ba42527 ]

The function quirks_param_set() takes as argument a const char* pointer
to the new value of the usbcore.quirks parameter. It then casts this
pointer to a non-const char* pointer and passes it to the strsep()
function, which overwrites the value.

Fix this by creating a copy of the value using kstrdup() and letting
that copy be written to by strsep().

Fixes: 027bd6cafd ("usb: core: Add "quirks" parameter for usbcore")
Signed-off-by: Kars Mulder <kerneldev@karsmulder.nl>

Link: https://lore.kernel.org/r/5ee2-5f048a00-21-618c5c00@230659773
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Kars Mulder 2020-07-07 16:43:50 +02:00 • committed by Greg Kroah-Hartman
parent ac780c229e
commit ebb2342360
1 changed files with 12 additions and 4 deletions

16
drivers/usb/core/quirks.c
View file

@ -25,17 +25,23 @@ static unsigned int quirk_count;
static char quirks_param[128];
static int quirks_param_set(const char *val, const struct kernel_param *kp)
static int quirks_param_set(const char *value, const struct kernel_param *kp)
{
char *p, *field;
char *val, *p, *field;
u16 vid, pid;
u32 flags;
size_t i;
int err;
val = kstrdup(value, GFP_KERNEL);
if (!val)
return -ENOMEM;
err = param_set_copystring(val, kp);
if (err)
if (err) {
kfree(val);
return err;
}
mutex_lock(&quirk_mutex);
@ -60,10 +66,11 @@ static int quirks_param_set(const char *val, const struct kernel_param *kp)
if (!quirk_list) {
quirk_count = 0;
mutex_unlock(&quirk_mutex);
kfree(val);
return -ENOMEM;
}
for (i = 0, p = (char *)val; p && *p;) {
for (i = 0, p = val; p && *p;) {
/* Each entry consists of VID:PID:flags */
field = strsep(&p, ":");
if (!field)
@ -144,6 +151,7 @@ static int quirks_param_set(const char *val, const struct kernel_param *kp)
unlock:
mutex_unlock(&quirk_mutex);
kfree(val);
return 0;
}