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pinctrl: mvebu: prevent walking off the end of group array

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While investigating (ab)use of krealloc, David found this bug.  It's
unlikely to occur, but now we detect the condition and error out
appropriately.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
David Woodhouse 2013-03-16 12:44:32 +01:00 committed by Linus Walleij
parent 50cf7c8ab3
commit aaed651ff6
1 changed files with 21 additions and 12 deletions
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33
drivers/pinctrl/mvebu/pinctrl-mvebu.c
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@ -478,8 +478,12 @@ static const struct pinctrl_ops mvebu_pinctrl_ops = {
.dt_free_map = mvebu_pinctrl_dt_free_map,
};
static int _add_function(struct mvebu_pinctrl_function *funcs, const char *name)
static int _add_function(struct mvebu_pinctrl_function *funcs, int *funcsize,
const char *name)
{
if (*funcsize <= 0)
return -EOVERFLOW;
while (funcs->num_groups) {
/* function already there */
if (strcmp(funcs->name, name) == 0) {
@ -488,8 +492,12 @@ static int _add_function(struct mvebu_pinctrl_function *funcs, const char *name)
}
funcs++;
}
/* append new unique function */
funcs->name = name;
funcs->num_groups = 1;
(*funcsize)--;
return 0;
}
@ -497,12 +505,12 @@ static int mvebu_pinctrl_build_functions(struct platform_device *pdev,
struct mvebu_pinctrl *pctl)
{
struct mvebu_pinctrl_function *funcs;
int num = 0;
int num = 0, funcsize = pctl->desc.npins;
int n, s;
/* we allocate functions for number of pins and hope
* there are less unique functions than pins available */
funcs = devm_kzalloc(&pdev->dev, pctl->desc.npins *
* there are fewer unique functions than pins available */
funcs = devm_kzalloc(&pdev->dev, funcsize *
sizeof(struct mvebu_pinctrl_function), GFP_KERNEL);
if (!funcs)
return -ENOMEM;
@ -510,26 +518,27 @@ static int mvebu_pinctrl_build_functions(struct platform_device *pdev,
for (n = 0; n < pctl->num_groups; n++) {
struct mvebu_pinctrl_group *grp = &pctl->groups[n];
for (s = 0; s < grp->num_settings; s++) {
int ret;
/* skip unsupported settings on this variant */
if (pctl->variant &&
!(pctl->variant & grp->settings[s].variant))
continue;
/* check for unique functions and count groups */
if (_add_function(funcs, grp->settings[s].name))
ret = _add_function(funcs, &funcsize,
grp->settings[s].name);
if (ret == -EOVERFLOW)
dev_err(&pdev->dev,
"More functions than pins(%d)\n",
pctl->desc.npins);
if (ret < 0)
continue;
num++;
}
}
/* with the number of unique functions and it's groups known,
reallocate functions and assign group names */
funcs = krealloc(funcs, num * sizeof(struct mvebu_pinctrl_function),
GFP_KERNEL);
if (!funcs)
return -ENOMEM;
pctl->num_functions = num;
pctl->functions = funcs;