Buffer overflow when compiled with -D_FORTIFY_SOURCE=2

[malcolmlewis]

Hi
After building without errors on the openSUSE Build service with the default rpm opt flags, running;

mbpfan -f -v

Results in a buffer overflow error, this is with the 4.1.13 kernel and openSUSE Leap 42.1, it works fine on SLED 11 SP4 (3.0.101 kernel) and seem to have tracked it down to;

diff -Naur a/src/mbpfan.c b/src/mbpfan.c
--- a/src/mbpfan.c 2015-05-05 14:53:12.000000000 -0500
+++ b/src/mbpfan.c 2015-12-21 18:09:22.110045078 -0600
@@ -129,7 +129,7 @@
int counter;
for (counter = 0; counter < 10; counter++) {

•        char hwmon_path[strlen(path_begin)+1];
  

•        char hwmon_path[strlen(path_begin)+2];
  
       sprintf(hwmon_path, "%s%d", path_begin, counter);
  

It also works fine if I set -D_FORTIFY_SOURCE=0 (disable), I'm only a packager, not a coder so submit the above as a fix for your consideration.

I also note that the systemd service file using simple doesn't work in openSUSE but forking does.

Hardware: MacBook3,1 (Late 2007) Intel(R) Core(TM)2 Duo CPU T7300 @ 2.00GHz

[dgraziotin]

Hi, thank you for reporting this. I was actually not aware of the FORTIFY_SOURCE flag. I will investigate this in the upcoming weeks.