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memory: brcmstb_dpfe: fix array index out of bounds 

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: 2f330caff5 ("memory: brcmstb: Add driver for DPFE")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Markus Mayer <mmayer@broadcom.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
This commit is contained in:
Markus Mayer 2020-08-22 13:50:00 -07:00 committed by Krzysztof Kozlowski
parent 4da1edcf8f
commit f42ae4bbf9
1 changed files with 16 additions and 7 deletions
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23
drivers/memory/brcmstb_dpfe.c
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@ -188,11 +188,6 @@ struct brcmstb_dpfe_priv {
struct mutex lock; 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 * Forward declaration of our sysfs attribute functions, so we can declare the
* attribute data structures early. * 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) static bool is_dcpu_enabled(struct brcmstb_dpfe_priv *priv)
{ {
u32 val; u32 val;
@ -445,7 +454,7 @@ static int __send_command(struct brcmstb_dpfe_priv *priv, unsigned int cmd,
} }
if (resp != 0) { if (resp != 0) {
mutex_unlock(&priv->lock); mutex_unlock(&priv->lock);
return -ETIMEDOUT; return -ffs(DCPU_RET_ERR_TIMEDOUT);
} }
/* Compute checksum over the message */ /* 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); ret = __send_command(priv, command, response);
if (ret < 0) if (ret < 0)
return sprintf(buf, "ERROR: %s\n", error_text[-ret]); return sprintf(buf, "ERROR: %s\n", get_error_text(-ret));
return 0; return 0;
} }