The permissions set by the Sen2Cor installer are a bit weird:
root@8a507c82f30a:/# ll /Sen2Cor-02.09.00-Linux64
total 44
drwxr-sr-x 6 root root 4096 Apr 13 14:38 ./
drwxr-xr-x 1 root root 4096 Apr 13 14:34 ../
-rwx------ 1 root root 661 Apr 13 14:38 L2A_Bashrc* # here
-rw-r--r-- 1 root root 11959 Oct 1 2020 LICENSE.txt
-rw-r--r-- 1 root root 1441 Oct 1 2020 README.md
drwxr-sr-x 2 root root 4096 Apr 13 14:38 bin/
drwxr-xr-x 2 root root 4096 Feb 4 10:01 copyright/
drwxr-sr-x 3 root root 4096 Apr 13 14:38 lib/
drwxr-sr-x 3 root root 4096 Feb 4 10:01 share/
root@8a507c82f30a:/# ll /Sen2Cor-02.09.00-Linux64/bin/
total 18812
drwxr-sr-x 2 root root 4096 Apr 13 14:38 ./
drwxr-sr-x 6 root root 4096 Apr 13 14:38 ../
-rwx------ 1 root root 178 Apr 13 14:38 L2A_Process* # here
-rwxr-xr-x 1 root root 2122344 Apr 13 14:38 gdal_translate*
-rwxr-xr-x 1 root root 2118248 Apr 13 14:38 gdaladdo*
-rwxr-xr-x 1 root root 2114152 Apr 13 14:38 gdalbuildvrt*
-rwxr-xr-x 1 root root 2114152 Apr 13 14:38 gdaldem*
-rwxr-xr-x 1 root root 2114152 Apr 13 14:38 gdalinfo*
-rwxr-xr-x 1 root root 2118248 Apr 13 14:38 gdalwarp*
-rwxr-xr-x 1 root root 2282088 Apr 13 14:38 h52gif*
-rwxr-xr-x 1 root root 2126440 Apr 13 14:38 ogrinfo*
lrwxrwxrwx 1 root root 39 Apr 13 14:38 python -> /Sen2Cor-02.09.00-Linux64/bin/python2.7*
lrwxrwxrwx 1 root root 39 Apr 13 14:38 python2 -> /Sen2Cor-02.09.00-Linux64/bin/python2.7*
-rwxr-xr-x 1 root root 2110056 Apr 13 14:38 python2.7*
root@8a507c82f30a:/# ll /root/sen2cor/2.9/
total 12
drwx------ 3 root root 4096 Apr 13 14:38 ./
drwx------ 3 root root 4096 Apr 13 14:38 ../
drwx------ 2 root root 4096 Apr 13 14:38 cfg/ # here
root@8a507c82f30a:/# ll /root/sen2cor/2.9/cfg
total 16
drwx------ 2 root root 4096 Apr 13 14:38 ./
drwx------ 3 root root 4096 Apr 13 14:38 ../
-rw------- 1 root root 6588 Apr 13 14:38 L2A_GIPP.xml # here
On Unix, it’s idiomatic to set permissions for executables and directories to 755, and to 644 to data files, unless they contain sensitive information. Some of the files (marked above) are instead not accessible by other users. This means that if a system administrator installs a per-machine Sen2Cor instance, she needs to make sure to update these permissions to more reasonable values for non-root users to be able to run the processor.