Under certain conditions, the output of "multipath -ll" or
"multipathd show topology", or the multipathd logs, may
contain garbage characters. Fix that by making sure that
the strings are always properly zero-terminated.
Note 1: The way this is coded, the previously written
character is overwritten by the newline. That behavior is
unchanged by this patch. I didn't want to fuzz with the
carefully crafted print.c code more than necessary at
this point.
Note 2: The condition (c <= line + len - 1) is equivalent to
(TAIL >= 0). It should always hold the way ENDLINE is called
after PRINT and PAD in print.c, and is only added as an
additional safeguard, e.g. against future code changes.
---
libmultipath/print.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/libmultipath/print.c b/libmultipath/print.c
index 7c2a1588..3a07fcf5 100644
--- a/libmultipath/print.c
+++ b/libmultipath/print.c
@@ -40,8 +40,14 @@ do { \
} while (0)
#define ENDLINE \
- if (c > line) \
- line[c - line - 1] = '\n'
+ if (c > line) { \
+ if (c <= line + len - 1) { \
+ *(c - 1) = '\n'; \
+ *c = '\0'; \
+ } else \
+ line[len - 1] = '\0'; \
+ }
+
#define PRINT(var, size, format, args...) \
do { \
fwd = snprintf(var, size, format, ##args); \
--
2.12.2
--
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