Bug 111

When run with a large number of environment variables, sudo will print "Memory 
fault" and exit.

sudo was configured with "./configure --without-lecture" and compiled using the 
HP ANSII C compiler.

Normal testing indicated that sudo was working correctly. However when running 
as the Big Brother user with the Big Brother environment loaded (as a Big 
Brother external script for example) sudo would fail with the "Memory fault" 
error above. Tests showed that this was the case for all users with the Big 
Brother environment variables set.

Big Brother sets about 200 environment variables.

Investigation showed that the bug is in the function insert_env in file env.c.
Memory is allocated for the environment pointers in slabs of 128 entries. The 
first slab will be allocated when the first entry is stored. When the 129th 
entry is about to be allocated, the test "if (env_len + 1 > env_size)" will be 
true and another 128 entries will be allocated. This however does not allow for 
the null pointer stored after the last entry, so when the 128th entry is stored 
in the array, the null entry will be written outside the allocated memory.

Changing

        if (env_len + 1 > env_size) {

to

        if (env_len + 2 > env_size) {

near the top of the function insert_env in env.c (line 251 in my copy of the 
source for version 1.6.7p4) solves the problem. Recompiling and installing the 
new version allows the Big Brother scripts to run correctly.