memory: brcmstb_dpfe: fix array index out of bounds (f42ae4bb) · Commits · 戴 / test

We would overrun the error_text array if we hit a TIMEOUT condition, because we were using the error code "ETIMEDOUT" (which is 110) as an array index. We fix the problem by correcting the array index and by providing a function to retrieve error messages rather than accessing the array directly. The function includes a bounds check that prevents the array from being overrun. Link: https://lore.kernel.org/linux-arm-kernel/38d00022-730c-948a-917c-d86382df8cb9@canonical.com/ Link: https://lore.kernel.org/r/20200822205000.15841-1-mmayer@broadcom.com Fixes: ("memory: brcmstb: Add driver for DPFE") Reported-by:

drivers/memory/brcmstb_dpfe.c

+16 −7

Original line number	Diff line number	Diff line
		@@ -188,11 +188,6 @@ struct brcmstb_dpfe_priv {
		struct mutex lock;
		};

		static const char * const error_text[] = {
		"Success", "Header code incorrect", "Unknown command or argument",
		"Incorrect checksum", "Malformed command", "Timed out",
		};

		/*
		* Forward declaration of our sysfs attribute functions, so we can declare the
		* attribute data structures early.
		@@ -307,6 +302,20 @@ static const struct dpfe_api dpfe_api_v3 = {
		},
		};

		static const char *get_error_text(unsigned int i)
		{
		static const char * const error_text[] = {
		"Success", "Header code incorrect",
		"Unknown command or argument", "Incorrect checksum",
		"Malformed command", "Timed out", "Unknown error",
		};

		if (unlikely(i >= ARRAY_SIZE(error_text)))
		i = ARRAY_SIZE(error_text) - 1;

		return error_text[i];
		}

		static bool is_dcpu_enabled(struct brcmstb_dpfe_priv *priv)
		{
		u32 val;
		@@ -445,7 +454,7 @@ static int __send_command(struct brcmstb_dpfe_priv *priv, unsigned int cmd,
		}
		if (resp != 0) {
		mutex_unlock(&priv->lock);
		return -ETIMEDOUT;
		return -ffs(DCPU_RET_ERR_TIMEDOUT);
		}

		/* Compute checksum over the message */
		@@ -695,7 +704,7 @@ static ssize_t generic_show(unsigned int command, u32 response[],

		ret = __send_command(priv, command, response);
		if (ret < 0)
		return sprintf(buf, "ERROR: %s\n", error_text[-ret]);
		return sprintf(buf, "ERROR: %s\n", get_error_text(-ret));

		return 0;
		}