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Subject[PATCH] tty: nozomi: Use scnprintf() for avoiding potential buffer overflow
Date
Since snprintf() returns the would-be-output size instead of the
actual output size, the succeeding calls may go beyond the given
buffer limit. Fix it by replacing with scnprintf().

Also rewrite the code in a standard if-form instead of ugly
conditional operators.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
drivers/tty/nozomi.c | 67 ++++++++++++++++++++++++++--------------------------
1 file changed, 33 insertions(+), 34 deletions(-)

diff --git a/drivers/tty/nozomi.c b/drivers/tty/nozomi.c
index ed99948f3b7f..3af193343f60 100644
--- a/drivers/tty/nozomi.c
+++ b/drivers/tty/nozomi.c
@@ -839,40 +839,39 @@ static char *interrupt2str(u16 interrupt)
static char buf[TMP_BUF_MAX];
char *p = buf;

- interrupt & MDM_DL1 ? p += snprintf(p, TMP_BUF_MAX, "MDM_DL1 ") : NULL;
- interrupt & MDM_DL2 ? p += snprintf(p, TMP_BUF_MAX - (p - buf),
- "MDM_DL2 ") : NULL;
-
- interrupt & MDM_UL1 ? p += snprintf(p, TMP_BUF_MAX - (p - buf),
- "MDM_UL1 ") : NULL;
- interrupt & MDM_UL2 ? p += snprintf(p, TMP_BUF_MAX - (p - buf),
- "MDM_UL2 ") : NULL;
-
- interrupt & DIAG_DL1 ? p += snprintf(p, TMP_BUF_MAX - (p - buf),
- "DIAG_DL1 ") : NULL;
- interrupt & DIAG_DL2 ? p += snprintf(p, TMP_BUF_MAX - (p - buf),
- "DIAG_DL2 ") : NULL;
-
- interrupt & DIAG_UL ? p += snprintf(p, TMP_BUF_MAX - (p - buf),
- "DIAG_UL ") : NULL;
-
- interrupt & APP1_DL ? p += snprintf(p, TMP_BUF_MAX - (p - buf),
- "APP1_DL ") : NULL;
- interrupt & APP2_DL ? p += snprintf(p, TMP_BUF_MAX - (p - buf),
- "APP2_DL ") : NULL;
-
- interrupt & APP1_UL ? p += snprintf(p, TMP_BUF_MAX - (p - buf),
- "APP1_UL ") : NULL;
- interrupt & APP2_UL ? p += snprintf(p, TMP_BUF_MAX - (p - buf),
- "APP2_UL ") : NULL;
-
- interrupt & CTRL_DL ? p += snprintf(p, TMP_BUF_MAX - (p - buf),
- "CTRL_DL ") : NULL;
- interrupt & CTRL_UL ? p += snprintf(p, TMP_BUF_MAX - (p - buf),
- "CTRL_UL ") : NULL;
-
- interrupt & RESET ? p += snprintf(p, TMP_BUF_MAX - (p - buf),
- "RESET ") : NULL;
+ if (interrupt & MDM_DL1)
+ p += scnprintf(p, TMP_BUF_MAX, "MDM_DL1 ");
+ if (interrupt & MDM_DL2)
+ p += scnprintf(p, TMP_BUF_MAX - (p - buf), "MDM_DL2 ");
+ if (interrupt & MDM_UL1)
+ p += scnprintf(p, TMP_BUF_MAX - (p - buf), "MDM_UL1 ");
+ if (interrupt & MDM_UL2)
+ p += scnprintf(p, TMP_BUF_MAX - (p - buf), "MDM_UL2 ");
+ if (interrupt & DIAG_DL1)
+ p += scnprintf(p, TMP_BUF_MAX - (p - buf), "DIAG_DL1 ");
+ if (interrupt & DIAG_DL2)
+ p += scnprintf(p, TMP_BUF_MAX - (p - buf), "DIAG_DL2 ");
+
+ if (interrupt & DIAG_UL)
+ p += scnprintf(p, TMP_BUF_MAX - (p - buf), "DIAG_UL ");
+
+ if (interrupt & APP1_DL)
+ p += scnprintf(p, TMP_BUF_MAX - (p - buf), "APP1_DL ");
+ if (interrupt & APP2_DL)
+ p += scnprintf(p, TMP_BUF_MAX - (p - buf), "APP2_DL ");
+
+ if (interrupt & APP1_UL)
+ p += scnprintf(p, TMP_BUF_MAX - (p - buf), "APP1_UL ");
+ if (interrupt & APP2_UL)
+ p += scnprintf(p, TMP_BUF_MAX - (p - buf), "APP2_UL ");
+
+ if (interrupt & CTRL_DL)
+ p += scnprintf(p, TMP_BUF_MAX - (p - buf), "CTRL_DL ");
+ if (interrupt & CTRL_UL)
+ p += scnprintf(p, TMP_BUF_MAX - (p - buf), "CTRL_UL ");
+
+ if (interrupt & RESET)
+ p += scnprintf(p, TMP_BUF_MAX - (p - buf), "RESET ");

return buf;
}
--
2.16.4
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