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linux/drivers/clk/visconti/pll.h

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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (c) 2021 TOSHIBA CORPORATION
* Copyright (c) 2021 Toshiba Electronic Devices & Storage Corporation
*
* Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
*/
#ifndef _VISCONTI_PLL_H_
#define _VISCONTI_PLL_H_
#include <linux/clk-provider.h>
#include <linux/regmap.h>
#include <linux/spinlock.h>
struct visconti_pll_provider {
void __iomem *reg_base;
struct device_node *node;
clk: visconti: Fix undefined behavior bug in struct visconti_pll_provider `struct clk_hw_onecell_data` is a flexible structure, which means that it contains flexible-array member at the bottom, in this case array `hws`: include/linux/clk-provider.h: 1380 struct clk_hw_onecell_data { 1381 unsigned int num; 1382 struct clk_hw *hws[] __counted_by(num); 1383 }; This could potentially lead to an overwrite of the objects following `clk_data` in `struct visconti_pll_provider`, in this case `struct device_node *node;`, at run-time: drivers/clk/visconti/pll.h: 16 struct visconti_pll_provider { 17 void __iomem *reg_base; 18 struct clk_hw_onecell_data clk_data; 19 struct device_node *node; 20 }; Notice that a total of 56 bytes are allocated for flexible-array `hws` at line 328. See below: include/dt-bindings/clock/toshiba,tmpv770x.h: 14 #define TMPV770X_NR_PLL 7 drivers/clk/visconti/pll-tmpv770x.c: 69 ctx = visconti_init_pll(np, reg_base, TMPV770X_NR_PLL); drivers/clk/visconti/pll.c: 321 struct visconti_pll_provider * __init visconti_init_pll(struct device_node *np, 322 void __iomem *base, 323 unsigned long nr_plls) 324 { 325 struct visconti_pll_provider *ctx; ... 328 ctx = kzalloc(struct_size(ctx, clk_data.hws, nr_plls), GFP_KERNEL); `struct_size(ctx, clk_data.hws, nr_plls)` above translates to sizeof(struct visconti_pll_provider) + sizeof(struct clk_hw *) * 7 == 24 + 8 * 7 == 24 + 56 ^^^^ | allocated bytes for flex array `hws` $ pahole -C visconti_pll_provider drivers/clk/visconti/pll.o struct visconti_pll_provider { void * reg_base; /* 0 8 */ struct clk_hw_onecell_data clk_data; /* 8 8 */ struct device_node * node; /* 16 8 */ /* size: 24, cachelines: 1, members: 3 */ /* last cacheline: 24 bytes */ }; And then, after the allocation, some data is written into all members of `struct visconti_pll_provider`: 332 for (i = 0; i < nr_plls; ++i) 333 ctx->clk_data.hws[i] = ERR_PTR(-ENOENT); 334 335 ctx->node = np; 336 ctx->reg_base = base; 337 ctx->clk_data.num = nr_plls; Fix all these by placing the declaration of object `clk_data` at the end of `struct visconti_pll_provider`. Also, add a comment to make it clear that this object must always be last in the structure, and prevent this bug from being introduced again in the future. -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting ready to enable it globally. Fixes: b4cbe606dc36 ("clk: visconti: Add support common clock driver and reset driver") Cc: stable@vger.kernel.org Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Link: https://lore.kernel.org/r/57a831d94ee2b3889b11525d4ad500356f89576f.1697492890.git.gustavoars@kernel.org Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2023-10-16 15:05:27 -07:00
/* Must be last */
struct clk_hw_onecell_data clk_data;
};
#define VISCONTI_PLL_RATE(_rate, _dacen, _dsmen, \
_refdiv, _intin, _fracin, _postdiv1, _postdiv2) \
{ \
.rate = _rate, \
.dacen = _dacen, \
.dsmen = _dsmen, \
.refdiv = _refdiv, \
.intin = _intin, \
.fracin = _fracin, \
.postdiv1 = _postdiv1, \
.postdiv2 = _postdiv2 \
}
struct visconti_pll_rate_table {
unsigned long rate;
unsigned int dacen;
unsigned int dsmen;
unsigned int refdiv;
unsigned long intin;
unsigned long fracin;
unsigned int postdiv1;
unsigned int postdiv2;
};
struct visconti_pll_info {
unsigned int id;
const char *name;
const char *parent;
unsigned long base_reg;
const struct visconti_pll_rate_table *rate_table;
};
struct visconti_pll_provider * __init visconti_init_pll(struct device_node *np,
void __iomem *base,
unsigned long nr_plls);
void visconti_register_plls(struct visconti_pll_provider *ctx,
const struct visconti_pll_info *list,
unsigned int nr_plls, spinlock_t *lock);
#endif /* _VISCONTI_PLL_H_ */