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clk: Sanitize possible_parent_show to Handle Return Value of of_clk_get_parent_name

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commit ceb87a361d0b079ecbc7d2831618c19087f304a9 upstream.

In the possible_parent_show function, ensure proper handling of the return
value from of_clk_get_parent_name to prevent potential issues arising from
a NULL return.
The current implementation invokes seq_puts directly on the result of
of_clk_get_parent_name without verifying the return value, which can lead
to kernel panic if the function returns NULL.

This patch addresses the concern by introducing a check on the return
value of of_clk_get_parent_name. If the return value is not NULL, the
function proceeds to call seq_puts, providing the returned value as
argument.
However, if of_clk_get_parent_name returns NULL, the function provides a
static string as argument, avoiding the panic.

Fixes: 1ccc0ddf04 ("clk: Use seq_puts() in possible_parent_show()")
Reported-by: Philip Daly <pdaly@redhat.com>
Signed-off-by: Alessandro Carminati (Red Hat) <alessandro.carminati@gmail.com>
Link: https://lore.kernel.org/r/20230921073217.572151-1-alessandro.carminati@gmail.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alessandro Carminati 2023-09-21 07:32:17 +00:00 committed by Greg Kroah-Hartman
parent 09ce0d85cc
commit d8928befff
1 changed files with 12 additions and 9 deletions
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21
drivers/clk/clk.c
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@ -3167,6 +3167,7 @@ static void possible_parent_show(struct seq_file *s, struct clk_core *core,
unsigned int i, char terminator)
{
struct clk_core *parent;
const char *name = NULL;
/*
* Go through the following options to fetch a parent's name.
@ -3181,18 +3182,20 @@ static void possible_parent_show(struct seq_file *s, struct clk_core *core,
* registered (yet).
*/
parent = clk_core_get_parent_by_index(core, i);
if (parent)
if (parent) {
seq_puts(s, parent->name);
else if (core->parents[i].name)
} else if (core->parents[i].name) {
seq_puts(s, core->parents[i].name);
else if (core->parents[i].fw_name)
} else if (core->parents[i].fw_name) {
seq_printf(s, "<%s>(fw)", core->parents[i].fw_name);
else if (core->parents[i].index >= 0)
seq_puts(s,
of_clk_get_parent_name(core->of_node,
core->parents[i].index));
else
seq_puts(s, "(missing)");
} else {
if (core->parents[i].index >= 0)
name = of_clk_get_parent_name(core->of_node, core->parents[i].index);
if (!name)
name = "(missing)";
seq_puts(s, name);
}
seq_putc(s, terminator);
}