[RESEND PATCH v2 5/5] lib: utils/irqchip: plic: Ensure no out-of-bound access in context save/restore helpers

Anup Patel anup at brainfault.org
Thu Dec 8 21:37:28 PST 2022


On Sun, Dec 4, 2022 at 10:48 AM Bin Meng <bmeng at tinylab.org> wrote:
>
> Currently the context save/restore helpers writes/reads the provided
> array using an index whose maximum value is determined by PLIC, which
> potentially may disagree with the caller to these helpers.
>
> Add a parameter to ask the caller to provide the size limit of the
> array to ensure no out-of-bound access happens.
>
> Signed-off-by: Bin Meng <bmeng at tinylab.org>
>
> ---
>
> Changes in v2:
> - new patch: lib: utils/irqchip: plic: Ensure no out-of-bound access in context save/restore helpers
>
>  include/sbi_utils/irqchip/fdt_irqchip_plic.h |  5 +++--
>  include/sbi_utils/irqchip/plic.h             |  4 ++--
>  lib/utils/irqchip/fdt_irqchip_plic.c         | 21 ++++++++++++++------
>  lib/utils/irqchip/plic.c                     | 12 ++++-------
>  platform/generic/allwinner/sun20i-d1.c       |  5 +++--
>  5 files changed, 27 insertions(+), 20 deletions(-)
>
> diff --git a/include/sbi_utils/irqchip/fdt_irqchip_plic.h b/include/sbi_utils/irqchip/fdt_irqchip_plic.h
> index 5f3f54d..f855454 100644
> --- a/include/sbi_utils/irqchip/fdt_irqchip_plic.h
> +++ b/include/sbi_utils/irqchip/fdt_irqchip_plic.h
> @@ -13,9 +13,10 @@ void fdt_plic_priority_save(u8 *priority, u32 num);
>
>  void fdt_plic_priority_restore(const u8 *priority, u32 num);
>
> -void fdt_plic_context_save(bool smode, u32 *enable, u32 *threshold);
> +void fdt_plic_context_save(bool smode, u32 *enable, u32 *threshold, u32 num);
>
> -void fdt_plic_context_restore(bool smode, const u32 *enable, u32 threshold);
> +void fdt_plic_context_restore(bool smode, const u32 *enable, u32 threshold,
> +                             u32 num);
>
>  void thead_plic_restore(void);
>
> diff --git a/include/sbi_utils/irqchip/plic.h b/include/sbi_utils/irqchip/plic.h
> index 38704a1..112a714 100644
> --- a/include/sbi_utils/irqchip/plic.h
> +++ b/include/sbi_utils/irqchip/plic.h
> @@ -24,10 +24,10 @@ void plic_priority_restore(const struct plic_data *plic, const u8 *priority,
>                            u32 num);
>
>  void plic_context_save(const struct plic_data *plic, int context_id,
> -                      u32 *enable, u32 *threshold);
> +                      u32 *enable, u32 *threshold, u32 num);
>
>  void plic_context_restore(const struct plic_data *plic, int context_id,
> -                         const u32 *enable, u32 threshold);
> +                         const u32 *enable, u32 threshold, u32 num);
>
>  int plic_context_init(const struct plic_data *plic, int context_id,
>                       bool enable, u32 threshold);
> diff --git a/lib/utils/irqchip/fdt_irqchip_plic.c b/lib/utils/irqchip/fdt_irqchip_plic.c
> index 87fb9bd..e975415 100644
> --- a/lib/utils/irqchip/fdt_irqchip_plic.c
> +++ b/lib/utils/irqchip/fdt_irqchip_plic.c
> @@ -42,22 +42,31 @@ void fdt_plic_priority_restore(const u8 *priority, u32 num)
>         plic_priority_restore(plic, priority, num);
>  }
>
> -void fdt_plic_context_save(bool smode, u32 *enable, u32 *threshold)
> +void fdt_plic_context_save(bool smode, u32 *enable, u32 *threshold, u32 num)
>  {
>         u32 hartid = current_hartid();
> +       struct plic_data *plic = plic_hartid2data[hartid];
> +       u32 ie_words = plic->num_src / 32 + 1;
>
> -       plic_context_save(plic_hartid2data[hartid],
> +       if (num > ie_words)
> +               num = ie_words;

Move this "if ()" block to plic_context_save() function.

> +       plic_context_save(plic,
>                           plic_hartid2context[hartid][smode],
> -                         enable, threshold);
> +                         enable, threshold, num);
>  }
>
> -void fdt_plic_context_restore(bool smode, const u32 *enable, u32 threshold)
> +void fdt_plic_context_restore(bool smode, const u32 *enable, u32 threshold,
> +                             u32 num)
>  {
>         u32 hartid = current_hartid();
> +       struct plic_data *plic = plic_hartid2data[hartid];
> +       u32 ie_words = plic->num_src / 32 + 1;
>
> -       plic_context_restore(plic_hartid2data[hartid],
> +       if (num > ie_words)
> +               num = ie_words;

Same as above, move this "if ()" block to plic_context_restore() function.

> +       plic_context_restore(plic,
>                              plic_hartid2context[hartid][smode],
> -                            enable, threshold);
> +                            enable, threshold, num);
>  }
>
>  static int irqchip_plic_warm_init(void)
> diff --git a/lib/utils/irqchip/plic.c b/lib/utils/irqchip/plic.c
> index 0a1596c..5922c75 100644
> --- a/lib/utils/irqchip/plic.c
> +++ b/lib/utils/irqchip/plic.c
> @@ -92,22 +92,18 @@ static void plic_set_ie(const struct plic_data *plic, u32 cntxid,
>  }
>
>  void plic_context_save(const struct plic_data *plic, int context_id,
> -                      u32 *enable, u32 *threshold)
> +                      u32 *enable, u32 *threshold, u32 num)
>  {
> -       u32 ie_words = plic->num_src / 32 + 1;
> -
> -       for (u32 i = 0; i < ie_words; i++)
> +       for (u32 i = 0; i < num; i++)
>                 enable[i] = plic_get_ie(plic, context_id, i);
>
>         *threshold = plic_get_thresh(plic, context_id);
>  }
>
>  void plic_context_restore(const struct plic_data *plic, int context_id,
> -                         const u32 *enable, u32 threshold)
> +                         const u32 *enable, u32 threshold, u32 num)
>  {
> -       u32 ie_words = plic->num_src / 32 + 1;
> -
> -       for (u32 i = 0; i < ie_words; i++)
> +       for (u32 i = 0; i < num; i++)
>                 plic_set_ie(plic, context_id, i, enable[i]);
>
>         plic_set_thresh(plic, context_id, threshold);
> diff --git a/platform/generic/allwinner/sun20i-d1.c b/platform/generic/allwinner/sun20i-d1.c
> index 46d336f..f6f7df1 100644
> --- a/platform/generic/allwinner/sun20i-d1.c
> +++ b/platform/generic/allwinner/sun20i-d1.c
> @@ -78,7 +78,7 @@ static u32 plic_threshold;
>
>  static void sun20i_d1_plic_save(void)
>  {
> -       fdt_plic_context_save(true, plic_sie, &plic_threshold);
> +       fdt_plic_context_save(true, plic_sie, &plic_threshold, PLIC_IE_WORDS);
>         fdt_plic_priority_save(plic_priority, PLIC_SOURCES);
>  }
>
> @@ -86,7 +86,8 @@ static void sun20i_d1_plic_restore(void)
>  {
>         thead_plic_restore();
>         fdt_plic_priority_restore(plic_priority, PLIC_SOURCES);
> -       fdt_plic_context_restore(true, plic_sie, plic_threshold);
> +       fdt_plic_context_restore(true, plic_sie, plic_threshold,
> +                                PLIC_IE_WORDS);
>  }
>
>  /*
> --
> 2.34.1
>
>
> --
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Regards,
Anup



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