pktgen: fix out-of-bounds access in pgctrl_write()
If a privileged user writes an empty string to /proc/net/pktgen/pgctrl
the code for stripping the (then non-existent) '\n' actually writes the
zero byte at index -1 of data[]. The then still uninitialized array will
very likely fail the command matching tests and the pr_warning() at the
end will therefore leak stack bytes to the kernel log.
Fix those issues by simply ensuring we're passed a non-empty string as
the user API apparently expects a trailing '\n' for all commands.
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index fdac61c..cc07c43 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -485,6 +485,9 @@
goto out;
}
+ if (count == 0)
+ return -EINVAL;
+
if (count > sizeof(data))
count = sizeof(data);
@@ -492,7 +495,7 @@
err = -EFAULT;
goto out;
}
- data[count - 1] = 0; /* Make string */
+ data[count - 1] = 0; /* Strip trailing '\n' and terminate string */
if (!strcmp(data, "stop"))
pktgen_stop_all_threads_ifs(pn);
